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https://dev.mysql.com/doc/refman/8.4/en/keyring-key-types.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="keyring-key-types">
</a>
8.4.4.10 Supported Keyring Key Types and Lengths
</h4>
</div>
</div>
</div>
<p>
MySQL Keyring supports keys of different types (encryption
algorithms) and lengths:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The available key types depend on which keyring plugin is
installed.
</p>
</li>
<li class="listitem">
<p>
The permitted key lengths are subject to multiple factors:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
General keyring loadable-function interface limits (for
keys managed using one of the keyring functions
described in
<a class="xref" href="keyring-functions-general-purpose.html" title="8.4.4.12 General-Purpose Keyring Key-Management Functions">
Section 8.4.4.12, “General-Purpose Keyring Key-Management Functions”
</a>
), or
limits from back end implementations. These length
limits can vary by key operation type.
</p>
</li>
<li class="listitem">
<p>
In addition to the general limits, individual keyring
plugins may impose restrictions on key lengths per key
type.
</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
<p>
<a class="xref" href="keyring-key-types.html#keyring-general-key-length-limits-table" title="Table 8.31 General Keyring Key Length Limits">
Table 8.31, “General Keyring Key Length Limits”
</a>
shows
the general key-length limits. (The lower limits for
<code class="literal">
keyring_aws
</code>
are imposed by the AWS KMS
interface, not the keyring functions.) For keyring plugins,
<a class="xref" href="keyring-key-types.html#keyring-key-types-table" title="Table 8.32 Keyring Plugin Key Types and Lengths">
Table 8.32, “Keyring Plugin Key Types and Lengths”
</a>
shows the key types
each keyring plugin permits, as well as any plugin-specific
key-length restrictions. For most keyring components, the
general key-length limits apply and there are no key-type
restrictions.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<code class="literal">
component_keyring_oci
</code>
can generate keys of
type
<code class="literal">
AES
</code>
with a size of 16, 24, or 32 bytes
only.
</p>
</div>
<div class="table">
<a name="keyring-general-key-length-limits-table">
</a>
<p class="title">
<b>
Table 8.31 General Keyring Key Length Limits
</b>
</p>
<div class="table-contents">
<table summary="General limits on keyring key lengths.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 80%"/>
</colgroup>
<thead>
<tr>
<th>
Key Operation
</th>
<th>
Maximum Key Length
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
Generate key
</td>
<td>
<p class="valid-value">
16,384 bytes (2,048 previously); 1,024 for
<code class="literal">
keyring_aws
</code>
</p>
</td>
</tr>
<tr>
<td>
Store key
</td>
<td>
<p class="valid-value">
16,384 bytes (2,048 previously); 4,096 for
<code class="literal">
keyring_aws
</code>
</p>
</td>
</tr>
<tr>
<td>
Fetch key
</td>
<td>
<p class="valid-value">
16,384 bytes (2,048 previously); 4,096 for
<code class="literal">
keyring_aws
</code>
</p>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a name="keyring-key-types-table">
</a>
<p class="title">
<b>
Table 8.32 Keyring Plugin Key Types and Lengths
</b>
</p>
<div class="table-contents">
<table summary="Key types and lengths supported by keyring plugins.">
<colgroup>
<col style="width: 30%"/>
<col style="width: 25%"/>
<col style="width: 45%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Plugin Name
</th>
<th scope="col">
Permitted Key Type
</th>
<th scope="col">
Plugin-Specific Length Restrictions
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row" valign="top">
<code class="literal">
keyring_aws
</code>
</th>
<td>
<p class="valid-value">
<code class="literal">
AES
</code>
</p>
<p class="valid-value">
<code class="literal">
SECRET
</code>
</p>
</td>
<td>
<p class="valid-value">
16, 24, or 32 bytes
</p>
<p class="valid-value">
None
</p>
</td>
</tr>
<tr>
<th scope="row" valign="top">
<code class="literal">
keyring_hashicorp
</code>
</th>
<td>
<p class="valid-value">
<code class="literal">
AES
</code>
</p>
<p class="valid-value">
<code class="literal">
DSA
</code>
</p>
<p class="valid-value">
<code class="literal">
RSA
</code>
</p>
<p class="valid-value">
<code class="literal">
SECRET
</code>
</p>
</td>
<td>
<p class="valid-value">
None
</p>
<p class="valid-value">
None
</p>
<p class="valid-value">
None
</p>
<p class="valid-value">
None
</p>
</td>
</tr>
<tr>
<th scope="row" valign="top">
<code class="literal">
keyring_okv
</code>
</th>
<td>
<p class="valid-value">
<code class="literal">
AES
</code>
</p>
<p class="valid-value">
<code class="literal">
SECRET
</code>
</p>
</td>
<td>
<p class="valid-value">
16, 24, or 32 bytes
</p>
<p class="valid-value">
None
</p>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
The
<code class="literal">
SECRET
</code>
key type is intended for
general-purpose storage of sensitive data using the MySQL
keyring, and is supported by most keyring components and keyring
plugins. The keyring encrypts and decrypts
<code class="literal">
SECRET
</code>
data as a byte stream upon storage and
retrieval.
</p>
<p>
Example keyring operations involving the
<code class="literal">
SECRET
</code>
key type:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa74989040"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> keyring_key_generate<span class="token punctuation">(</span><span class="token string">'MySecret1'</span><span class="token punctuation">,</span> <span class="token string">'SECRET'</span><span class="token punctuation">,</span> <span class="token number">20</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_remove<span class="token punctuation">(</span><span class="token string">'MySecret1'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_store<span class="token punctuation">(</span><span class="token string">'MySecret2'</span><span class="token punctuation">,</span> <span class="token string">'SECRET'</span><span class="token punctuation">,</span> <span class="token string">'MySecretData'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_fetch<span class="token punctuation">(</span><span class="token string">'MySecret2'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_length_fetch<span class="token punctuation">(</span><span class="token string">'MySecret2'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_type_fetch<span class="token punctuation">(</span><span class="token string">'MySecret2'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_remove<span class="token punctuation">(</span><span class="token string">'MySecret2'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-disk-write-speed-aggregate.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysql-cluster-ndbinfo-disk-write-speed-aggregate">
</a>
25.6.17.29 The ndbinfo disk_write_speed_aggregate Table
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045089506800">
</a>
<p>
The
<code class="literal">
disk_write_speed_aggregate
</code>
table provides
aggregated information about the speed of disk writes during
LCP, backup, and restore operations.
</p>
<p>
The
<code class="literal">
disk_write_speed_aggregate
</code>
table contains
the following columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
node_id
</code>
</p>
<p>
Node ID of this node
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
thr_no
</code>
</p>
<p>
Thread ID of this LDM thread
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
backup_lcp_speed_last_sec
</code>
</p>
<p>
Number of bytes written to disk by backup and LCP processes
in the last second
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
redo_speed_last_sec
</code>
</p>
<p>
Number of bytes written to REDO log in the last second
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
backup_lcp_speed_last_10sec
</code>
</p>
<p>
Number of bytes written to disk by backup and LCP processes
per second, averaged over the last 10 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
redo_speed_last_10sec
</code>
</p>
<p>
Number of bytes written to REDO log per second, averaged
over the last 10 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
std_dev_backup_lcp_speed_last_10sec
</code>
</p>
<p>
Standard deviation in number of bytes written to disk by
backup and LCP processes per second, averaged over the last
10 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
std_dev_redo_speed_last_10sec
</code>
</p>
<p>
Standard deviation in number of bytes written to REDO log
per second, averaged over the last 10 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
backup_lcp_speed_last_60sec
</code>
</p>
<p>
Number of bytes written to disk by backup and LCP processes
per second, averaged over the last 60 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
redo_speed_last_60sec
</code>
</p>
<p>
Number of bytes written to REDO log per second, averaged
over the last 10 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
std_dev_backup_lcp_speed_last_60sec
</code>
</p>
<p>
Standard deviation in number of bytes written to disk by
backup and LCP processes per second, averaged over the last
60 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
std_dev_redo_speed_last_60sec
</code>
</p>
<p>
Standard deviation in number of bytes written to REDO log
per second, averaged over the last 60 seconds
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
slowdowns_due_to_io_lag
</code>
</p>
<p>
Number of seconds since last node start that disk writes
were slowed due to REDO log I/O lag
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
slowdowns_due_to_high_cpu
</code>
</p>
<p>
Number of seconds since last node start that disk writes
were slowed due to high CPU usage
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
disk_write_speed_set_to_min
</code>
</p>
<p>
Number of seconds since last node start that disk write
speed was set to minimum
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
current_target_disk_write_speed
</code>
</p>
<p>
Actual speed of disk writes per LDM thread (aggregated)
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/static-format.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="static-format">
</a>
18.2.3.1 Static (Fixed-Length) Table Characteristics
</h4>
</div>
</div>
</div>
<p>
Static format is the default for
<code class="literal">
MyISAM
</code>
tables. It is used when the table contains no variable-length
columns (
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
VARCHAR
</code>
</a>
,
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
VARBINARY
</code>
</a>
,
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
BLOB
</code>
</a>
, or
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
TEXT
</code>
</a>
). Each row is stored using a
fixed number of bytes.
</p>
<p>
Of the three
<code class="literal">
MyISAM
</code>
storage formats, static
format is the simplest and most secure (least subject to
corruption). It is also the fastest of the on-disk formats due
to the ease with which rows in the data file can be found on
disk: To look up a row based on a row number in the index,
multiply the row number by the row length to calculate the row
position. Also, when scanning a table, it is very easy to read a
constant number of rows with each disk read operation.
</p>
<p>
The security is evidenced if your computer crashes while the
MySQL server is writing to a fixed-format
<code class="literal">
MyISAM
</code>
file. In this case,
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
can easily determine where each row
starts and ends, so it can usually reclaim all rows except the
partially written one.
<code class="literal">
MyISAM
</code>
table indexes
can always be reconstructed based on the data rows.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Fixed-length row format is available only for tables having no
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
BLOB
</code>
</a>
or
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
TEXT
</code>
</a>
columns. Creating a table
having such columns with an explicit
<code class="literal">
ROW_FORMAT
</code>
clause does not raise an error
or warning; the format specification is ignored.
</p>
</div>
<p>
Static-format tables have these characteristics:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
CHAR
</code>
</a>
and
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
VARCHAR
</code>
</a>
columns are
space-padded to the specified column width, although the
column type is not altered.
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
BINARY
</code>
</a>
and
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
VARBINARY
</code>
</a>
columns are padded
with
<code class="literal">
0x00
</code>
bytes to the column width.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
NULL
</code>
columns require additional space in
the row to record whether their values are
<code class="literal">
NULL
</code>
. Each
<code class="literal">
NULL
</code>
column
takes one bit extra, rounded up to the nearest byte.
</p>
</li>
<li class="listitem">
<p>
Very quick.
</p>
</li>
<li class="listitem">
<p>
Easy to cache.
</p>
</li>
<li class="listitem">
<p>
Easy to reconstruct after a crash, because rows are located
in fixed positions.
</p>
</li>
<li class="listitem">
<p>
Reorganization is unnecessary unless you delete a huge
number of rows and want to return free disk space to the
operating system. To do this, use
<a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
<code class="literal">
OPTIMIZE TABLE
</code>
</a>
or
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -r
</strong>
</span>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Usually require more disk space than dynamic-format tables.
</p>
</li>
<li class="listitem">
<p>
The expected row length in bytes for static-sized rows is
calculated using the following expression:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa33794558"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">row length = 1
+ (<em class="replaceable">sum of column lengths</em>)
+ (<em class="replaceable">number of NULL columns</em> + <em class="replaceable">delete_flag</em> + 7)/8
+ (<em class="replaceable">number of variable-length columns</em>)</code></pre>
</div>
<p>
<em class="replaceable">
<code>
delete_flag
</code>
</em>
is 1 for tables with
static row format. Static tables use a bit in the row record
for a flag that indicates whether the row has been deleted.
<em class="replaceable">
<code>
delete_flag
</code>
</em>
is 0 for dynamic
tables because the flag is stored in the dynamic row header.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/partitioning-handling-nulls.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="partitioning-handling-nulls">
</a>
26.2.7 How MySQL Partitioning Handles NULL
</h3>
</div>
</div>
</div>
<p>
Partitioning in MySQL does nothing to disallow
<code class="literal">
NULL
</code>
as the value of a partitioning
expression, whether it is a column value or the value of a
user-supplied expression. Even though it is permitted to use
<code class="literal">
NULL
</code>
as the value of an expression that must
otherwise yield an integer, it is important to keep in mind that
<code class="literal">
NULL
</code>
is not a number. MySQL's
partitioning implementation treats
<code class="literal">
NULL
</code>
as
being less than any non-
<code class="literal">
NULL
</code>
value, just as
<code class="literal">
ORDER BY
</code>
does.
</p>
<p>
This means that treatment of
<code class="literal">
NULL
</code>
varies
between partitioning of different types, and may produce
behavior which you do not expect if you are not prepared for it.
This being the case, we discuss in this section how each MySQL
partitioning type handles
<code class="literal">
NULL
</code>
values when
determining the partition in which a row should be stored, and
provide examples for each.
</p>
<p>
<b>
Handling of NULL with RANGE partitioning.
</b>
If you insert a row into a table partitioned by
<code class="literal">
RANGE
</code>
such that the column value used to
determine the partition is
<code class="literal">
NULL
</code>
, the row is
inserted into the lowest partition. Consider these two tables
in a database named
<code class="literal">
p
</code>
, created as follows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96340192"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token keyword">MAXVALUE</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.09 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t2 <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token keyword">MAXVALUE</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.09 sec)</span></code></pre>
</div>
<p>
You can see the partitions created by these two
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statements using the
following query against the
<a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
<code class="literal">
PARTITIONS
</code>
</a>
table in the
<code class="literal">
INFORMATION_SCHEMA
</code>
database:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa58056751"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span><span class="token punctuation">,</span> PARTITION_NAME<span class="token punctuation">,</span> TABLE_ROWS<span class="token punctuation">,</span> <span class="token keyword">AVG_ROW_LENGTH</span><span class="token punctuation">,</span> DATA_LENGTH
<span class="token operator">></span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PARTITIONS</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'p'</span> <span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">LIKE</span> <span class="token string">'t_'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span> PARTITION_NAME <span class="token punctuation">|</span> TABLE_ROWS <span class="token punctuation">|</span> AVG_ROW_LENGTH <span class="token punctuation">|</span> DATA_LENGTH <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p3 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">7 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
(For more information about this table, see
<a class="xref" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
Section 28.3.21, “The INFORMATION_SCHEMA PARTITIONS Table”
</a>
.) Now let
us populate each of these tables with a single row containing a
<code class="literal">
NULL
</code>
in the column used as the partitioning
key, and verify that the rows were inserted using a pair of
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa19560794"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t2 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NULL <span class="token punctuation">|</span> mothra <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t2<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NULL <span class="token punctuation">|</span> mothra <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
You can see which partitions are used to store the inserted rows
by rerunning the previous query against
<a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
<code class="literal">
INFORMATION_SCHEMA.PARTITIONS
</code>
</a>
and
inspecting the output:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa20967956"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span><span class="token punctuation">,</span> PARTITION_NAME<span class="token punctuation">,</span> TABLE_ROWS<span class="token punctuation">,</span> <span class="token keyword">AVG_ROW_LENGTH</span><span class="token punctuation">,</span> DATA_LENGTH
<span class="token operator">></span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PARTITIONS</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'p'</span> <span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">LIKE</span> <span class="token string">'t_'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span> PARTITION_NAME <span class="token punctuation">|</span> TABLE_ROWS <span class="token punctuation">|</span> AVG_ROW_LENGTH <span class="token punctuation">|</span> DATA_LENGTH <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation"></span><em><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span></em><span class="token punctuation"></span></span>
<span class="token output"><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t1 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation"></span><em><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span></em><span class="token punctuation"></span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> t2 <span class="token punctuation">|</span> p3 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">7 rows in set (0.01 sec)</span></code></pre>
</div>
<p>
You can also demonstrate that these rows were stored in the
lowest-numbered partition of each table by dropping these
partitions, and then re-running the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa94365096"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> t1 <span class="token keyword">DROP</span> <span class="token keyword">PARTITION</span> p0<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.16 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> t2 <span class="token keyword">DROP</span> <span class="token keyword">PARTITION</span> p0<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.16 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1<span class="token punctuation">;</span>
<span class="token output">Empty set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t2<span class="token punctuation">;</span>
<span class="token output">Empty set (0.00 sec)</span></code></pre>
</div>
<p>
(For more information on
<code class="literal">
ALTER TABLE ... DROP
PARTITION
</code>
, see
<a class="xref" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
Section 15.1.9, “ALTER TABLE Statement”
</a>
.)
</p>
<p>
<code class="literal">
NULL
</code>
is also treated in this way for
partitioning expressions that use SQL functions. Suppose that we
define a table using a
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE
TABLE
</code>
</a>
statement such as this one:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa66085761"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> tndate <span class="token punctuation">(</span>
id <span class="token datatype">INT</span><span class="token punctuation">,</span>
dt <span class="token datatype">DATE</span>
<span class="token punctuation">)</span>
<span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span> <span class="token function">YEAR</span><span class="token punctuation">(</span>dt<span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1990</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2000</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token keyword">MAXVALUE</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
As with other MySQL functions,
<a class="link" href="date-and-time-functions.html#function_year">
<code class="literal">
YEAR(NULL)
</code>
</a>
returns
<code class="literal">
NULL
</code>
. A row with a
<code class="literal">
dt
</code>
column value of
<code class="literal">
NULL
</code>
is treated as though the
partitioning expression evaluated to a value less than any other
value, and so is inserted into partition
<code class="literal">
p0
</code>
.
</p>
<p>
<b>
Handling of NULL with LIST partitioning.
</b>
A table that is partitioned by
<code class="literal">
LIST
</code>
admits
<code class="literal">
NULL
</code>
values if and only if one of its
partitions is defined using that value-list that contains
<code class="literal">
NULL
</code>
. The converse of this is that a table
partitioned by
<code class="literal">
LIST
</code>
which does not
explicitly use
<code class="literal">
NULL
</code>
in a value list rejects
rows resulting in a
<code class="literal">
NULL
</code>
value for the
partitioning expression, as shown in this example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa23415213"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> ts1 <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">LIST</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.01 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> ts1 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1504 (HY000)<span class="token punctuation">:</span> Table has no partition for value 9
</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> ts1 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1504 (HY000)<span class="token punctuation">:</span> Table has no partition for value NULL</span></code></pre>
</div>
<p>
Only rows having a
<code class="literal">
c1
</code>
value between
<code class="literal">
0
</code>
and
<code class="literal">
8
</code>
inclusive can be
inserted into
<code class="literal">
ts1
</code>
.
<code class="literal">
NULL
</code>
falls outside this range, just like the number
<code class="literal">
9
</code>
. We can create tables
<code class="literal">
ts2
</code>
and
<code class="literal">
ts3
</code>
having value
lists containing
<code class="literal">
NULL
</code>
, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa24609074"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> ts2 <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">LIST</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.01 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> ts3 <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">LIST</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">7</span><span class="token punctuation">,</span> <span class="token boolean">NULL</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.01 sec)</span></code></pre>
</div>
<p>
When defining value lists for partitioning, you can (and should)
treat
<code class="literal">
NULL
</code>
just as you would any other value.
For example, both
<code class="literal">
VALUES IN (NULL)
</code>
and
<code class="literal">
VALUES IN (1, 4, 7, NULL)
</code>
are valid, as are
<code class="literal">
VALUES IN (1, NULL, 4, 7)
</code>
,
<code class="literal">
VALUES IN
(NULL, 1, 4, 7)
</code>
, and so on. You can insert a row
having
<code class="literal">
NULL
</code>
for column
<code class="literal">
c1
</code>
into each of the tables
<code class="literal">
ts2
</code>
and
<code class="literal">
ts3
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa30132131"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> ts2 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> ts3 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span></code></pre>
</div>
<p>
By issuing the appropriate query against
<a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
<code class="literal">
INFORMATION_SCHEMA.PARTITIONS
</code>
</a>
, you
can determine which partitions were used to store the rows just
inserted (we assume, as in the previous examples, that the
partitioned tables were created in the
<code class="literal">
p
</code>
database):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa32413723"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span><span class="token punctuation">,</span> PARTITION_NAME<span class="token punctuation">,</span> TABLE_ROWS<span class="token punctuation">,</span> <span class="token keyword">AVG_ROW_LENGTH</span><span class="token punctuation">,</span> DATA_LENGTH
<span class="token operator">></span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PARTITIONS</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'p'</span> <span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">LIKE</span> <span class="token string">'ts_'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span> PARTITION_NAME <span class="token punctuation">|</span> TABLE_ROWS <span class="token punctuation">|</span> AVG_ROW_LENGTH <span class="token punctuation">|</span> DATA_LENGTH <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> ts2 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ts2 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ts2 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation"></span><em><span class="token punctuation">|</span> ts2 <span class="token punctuation">|</span> p3 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span></em><span class="token punctuation"></span></span>
<span class="token output"><span class="token punctuation">|</span> ts3 <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation"></span><em><span class="token punctuation">|</span> ts3 <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span></em><span class="token punctuation"></span></span>
<span class="token output"><span class="token punctuation">|</span> ts3 <span class="token punctuation">|</span> p2 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">7 rows in set (0.01 sec)</span></code></pre>
</div>
<p>
As shown earlier in this section, you can also verify which
partitions were used for storing the rows by deleting these
partitions and then performing a
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
.
</p>
<p>
<b>
Handling of NULL with HASH and KEY partitioning.
</b>
<code class="literal">
NULL
</code>
is handled somewhat differently for
tables partitioned by
<code class="literal">
HASH
</code>
or
<code class="literal">
KEY
</code>
. In these cases, any partition
expression that yields a
<code class="literal">
NULL
</code>
value is
treated as though its return value were zero. We can verify
this behavior by examining the effects on the file system of
creating a table partitioned by
<code class="literal">
HASH
</code>
and
populating it with a record containing appropriate values.
Suppose that you have a table
<code class="literal">
th
</code>
(also in
the
<code class="literal">
p
</code>
database) created using the following
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa74755355"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> th <span class="token punctuation">(</span>
<span class="token prompt"> -></span> c1 <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> c2 <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">HASH</span><span class="token punctuation">(</span>c1<span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITIONS</span> <span class="token number">2</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span></code></pre>
</div>
<p>
The partitions belonging to this table can be viewed using the
query shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42626089"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span><span class="token punctuation">,</span>PARTITION_NAME<span class="token punctuation">,</span>TABLE_ROWS<span class="token punctuation">,</span><span class="token keyword">AVG_ROW_LENGTH</span><span class="token punctuation">,</span>DATA_LENGTH
<span class="token operator">></span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PARTITIONS</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'p'</span> <span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">=</span><span class="token string">'th'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span> PARTITION_NAME <span class="token punctuation">|</span> TABLE_ROWS <span class="token punctuation">|</span> AVG_ROW_LENGTH <span class="token punctuation">|</span> DATA_LENGTH <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> th <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> th <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
<code class="literal">
TABLE_ROWS
</code>
for each partition is 0. Now
insert two rows into
<code class="literal">
th
</code>
whose
<code class="literal">
c1
</code>
column values are
<code class="literal">
NULL
</code>
and 0, and verify that these rows were inserted, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa72213250"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> th <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token string">'mothra'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token string">'gigan'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> th<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> c1 <span class="token punctuation">|</span> c2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NULL <span class="token punctuation">|</span> mothra <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> gigan <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.01 sec)</span></code></pre>
</div>
<p>
Recall that for any integer
<em class="replaceable">
<code>
N
</code>
</em>
, the
value of
<code class="literal">
NULL MOD
<em class="replaceable">
<code>
N
</code>
</em>
</code>
is always
<code class="literal">
NULL
</code>
. For tables that are partitioned by
<code class="literal">
HASH
</code>
or
<code class="literal">
KEY
</code>
, this result
is treated for determining the correct partition as
<code class="literal">
0
</code>
. Checking the Information Schema
<a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
<code class="literal">
PARTITIONS
</code>
</a>
table once again, we can
see that both rows were inserted into partition
<code class="literal">
p0
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa34461601"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span><span class="token punctuation">,</span> PARTITION_NAME<span class="token punctuation">,</span> TABLE_ROWS<span class="token punctuation">,</span> <span class="token keyword">AVG_ROW_LENGTH</span><span class="token punctuation">,</span> DATA_LENGTH
<span class="token operator">></span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PARTITIONS</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'p'</span> <span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">=</span><span class="token string">'th'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span> PARTITION_NAME <span class="token punctuation">|</span> TABLE_ROWS <span class="token punctuation">|</span> AVG_ROW_LENGTH <span class="token punctuation">|</span> DATA_LENGTH <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation"></span><em><span class="token punctuation">|</span> th <span class="token punctuation">|</span> p0 <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span> 20 <span class="token punctuation">|</span></em><span class="token punctuation"></span></span>
<span class="token output"><span class="token punctuation">|</span> th <span class="token punctuation">|</span> p1 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
By repeating the last example using
<code class="literal">
PARTITION BY
KEY
</code>
in place of
<code class="literal">
PARTITION BY HASH
</code>
in the definition of the table, you can verify that
<code class="literal">
NULL
</code>
is also treated like 0 for this type of
partitioning.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/binary-log-setting.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="binary-log-setting">
</a>
7.4.4.2 Setting The Binary Log Format
</h4>
</div>
</div>
</div>
<p>
You can select the binary logging format explicitly by starting
the MySQL server with
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="option">
--binlog-format=
<em class="replaceable">
<code>
type
</code>
</em>
</code>
</a>
.
The supported values for
<em class="replaceable">
<code>
type
</code>
</em>
are:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
STATEMENT
</code>
causes logging to be statement
based.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
ROW
</code>
causes logging to be row based. This
is the default.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MIXED
</code>
causes logging to use mixed format.
</p>
</li>
</ul>
</div>
<p>
Setting the binary logging format does not activate binary
logging for the server. The setting only takes effect when
binary logging is enabled on the server, which is the case when
the
<a class="link" href="replication-options-binary-log.html#sysvar_log_bin">
<code class="literal">
log_bin
</code>
</a>
system variable is
set to
<code class="literal">
ON
</code>
. In MySQL 8.4, binary
logging is enabled by default, and is disabled only if you start
the server with
<a class="link" href="replication-options-binary-log.html#option_mysqld_log-bin">
<code class="option">
--skip-log-bin
</code>
</a>
or
<a class="link" href="replication-options-binary-log.html#option_mysqld_log-bin">
<code class="option">
--disable-log-bin
</code>
</a>
.
</p>
<p>
The logging format also can be switched at runtime, although
note that there are a number of situations in which you cannot
do this, as discussed later in this section. Set the global
value of the
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
system variable to specify the format for clients that connect
subsequent to the change:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa7906507"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> binlog_format <span class="token operator">=</span> <span class="token string">'STATEMENT'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> binlog_format <span class="token operator">=</span> <span class="token string">'ROW'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> binlog_format <span class="token operator">=</span> <span class="token string">'MIXED'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
An individual client can control the logging format for its own
statements by setting the session value of
<code class="literal">
binlog_format
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa97630742"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">SESSION</span> binlog_format <span class="token operator">=</span> <span class="token string">'STATEMENT'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">SESSION</span> binlog_format <span class="token operator">=</span> <span class="token string">'ROW'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">SESSION</span> binlog_format <span class="token operator">=</span> <span class="token string">'MIXED'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Changing the global
<code class="literal">
binlog_format
</code>
value
requires privileges sufficient to set global system variables.
Changing the session
<code class="literal">
binlog_format
</code>
value
requires privileges sufficient to set restricted session system
variables. See
<a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
Section 7.1.9.1, “System Variable Privileges”
</a>
.
</p>
<p>
There are several reasons why a client might want to set binary
logging on a per-session basis:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
A session that makes many small changes to the database
might want to use row-based logging.
</p>
</li>
<li class="listitem">
<p>
A session that performs updates that match many rows in the
<code class="literal">
WHERE
</code>
clause might want to use
statement-based logging because it is more efficient to log
a few statements than many rows.
</p>
</li>
<li class="listitem">
<p>
Some statements require a lot of execution time on the
source, but result in just a few rows being modified. It
might therefore be beneficial to replicate them using
row-based logging.
</p>
</li>
</ul>
</div>
<p>
There are exceptions when you cannot switch the replication
format at runtime:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The replication format cannot be changed from within a
stored function or a trigger.
</p>
</li>
<li class="listitem">
<p>
If the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
storage engine is
enabled.
</p>
</li>
<li class="listitem">
<p>
If a session has open temporary tables, the replication
format cannot be changed for the session (
<code class="literal">
SET
@@SESSION.binlog_format
</code>
).
</p>
</li>
<li class="listitem">
<p>
If any replication channel has open temporary tables, the
replication format cannot be changed globally (
<code class="literal">
SET
@@GLOBAL.binlog_format
</code>
or
<code class="literal">
SET
@@PERSIST.binlog_format
</code>
).
</p>
</li>
<li class="listitem">
<p>
If any replication channel applier thread is currently
running, the replication format cannot be changed globally
(
<code class="literal">
SET @@GLOBAL.binlog_format
</code>
or
<code class="literal">
SET @@PERSIST.binlog_format
</code>
).
</p>
</li>
</ul>
</div>
<p>
Trying to switch the replication format in any of these cases
(or attempting to set the current replication format) results in
an error. You can, however, use
<code class="literal">
PERSIST_ONLY
</code>
(
<code class="literal">
SET @@PERSIST_ONLY.binlog_format
</code>
) to change
the replication format at any time, because this action does not
modify the runtime global system variable value, and takes
effect only after a server restart.
</p>
<p>
Switching the replication format at runtime is not recommended
when any temporary tables exist, because temporary tables are
logged only when using statement-based replication, whereas with
row-based replication and mixed replication, they are not
logged.
</p>
<p>
Switching the replication format while replication is ongoing
can also cause issues. Each MySQL Server can set its own and
only its own binary logging format (true whether
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
is set with
global or session scope). This means that changing the logging
format on a replication source server does not cause a replica
to change its logging format to match. When using
<code class="literal">
STATEMENT
</code>
mode, the
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
system variable
is not replicated. When using
<code class="literal">
MIXED
</code>
or
<code class="literal">
ROW
</code>
logging mode, it is replicated but is
ignored by the replica.
</p>
<p>
A replica is not able to convert binary log entries received in
<code class="literal">
ROW
</code>
logging format to
<code class="literal">
STATEMENT
</code>
format for use in its own binary
log. The replica must therefore use
<code class="literal">
ROW
</code>
or
<code class="literal">
MIXED
</code>
format if the source does. Changing the
binary logging format on the source from
<code class="literal">
STATEMENT
</code>
to
<code class="literal">
ROW
</code>
or
<code class="literal">
MIXED
</code>
while replication is ongoing to a
replica with
<code class="literal">
STATEMENT
</code>
format can cause
replication to fail with errors such as
<span class="errortext">
Error
executing row event: 'Cannot execute statement: impossible to
write to binary log since statement is in row format and
BINLOG_FORMAT = STATEMENT.'
</span>
Changing the binary
logging format on the replica to
<code class="literal">
STATEMENT
</code>
format when the source is still using
<code class="literal">
MIXED
</code>
or
<code class="literal">
ROW
</code>
format also causes the same type of
replication failure. To change the format safely, you must stop
replication and ensure that the same change is made on both the
source and the replica.
</p>
<p>
If you are using
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
tables and
the transaction isolation level is
<a class="link" href="innodb-transaction-isolation-levels.html#isolevel_read-committed">
<code class="literal">
READ
COMMITTED
</code>
</a>
or
<a class="link" href="innodb-transaction-isolation-levels.html#isolevel_read-uncommitted">
<code class="literal">
READ
UNCOMMITTED
</code>
</a>
, only row-based logging can be used. It is
<span class="emphasis">
<em>
possible
</em>
</span>
to change the logging format to
<code class="literal">
STATEMENT
</code>
, but doing so at runtime leads very
rapidly to errors because
<code class="literal">
InnoDB
</code>
can no
longer perform inserts.
</p>
<p>
With the binary log format set to
<code class="literal">
ROW
</code>
, many
changes are written to the binary log using the row-based
format. Some changes, however, still use the statement-based
format. Examples include all DDL (data definition language)
statements such as
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
,
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
, or
<a class="link" href="drop-table.html" title="15.1.32 DROP TABLE Statement">
<code class="literal">
DROP TABLE
</code>
</a>
.
</p>
<p>
When row-based binary logging is used, the
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_row_event_max_size">
<code class="literal">
binlog_row_event_max_size
</code>
</a>
system variable and its corresponding startup option
<a class="link" href="replication-options-binary-log.html#option_mysqld_binlog-row-event-max-size">
<code class="option">
--binlog-row-event-max-size
</code>
</a>
set a
soft limit on the maximum size of row events. The default value
is 8192 bytes, and the value can only be changed at server
startup. Where possible, rows stored in the binary log are
grouped into events with a size not exceeding the value of this
setting. If an event cannot be split, the maximum size can be
exceeded.
</p>
<p>
The
<a class="link" href="replication-options-binary-log.html#option_mysqld_binlog-row-event-max-size">
<code class="option">
--binlog-row-event-max-size
</code>
</a>
option is available for servers that are capable of row-based
replication. Rows are stored into the binary log in chunks
having a size in bytes not exceeding the value of this option.
The value must be a multiple of 256. The default value is 8192.
</p>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
When using
<span class="emphasis">
<em>
statement-based logging
</em>
</span>
for
replication, it is possible for the data on the source and
replica to become different if a statement is designed in such
a way that the data modification is
<span class="firstterm">
nondeterministic
</span>
; that
is, it is left up to the query optimizer. In general, this is
not a good practice even outside of replication. For a
detailed explanation of this issue, see
<a class="xref" href="known-issues.html" title="B.3.7 Known Issues in MySQL">
Section B.3.7, “Known Issues in MySQL”
</a>
.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-prepared-statements-instances-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="performance-schema-prepared-statements-instances-table">
</a>
29.12.6.4 The prepared_statements_instances Table
</h4>
</div>
</div>
</div>
<p>
The Performance Schema provides instrumentation for prepared
statements, for which there are two protocols:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The binary protocol. This is accessed through the MySQL C
API and maps onto underlying server commands as shown in
the following table.
</p>
<div class="informaltable">
<table summary="How the binary protocol accessed through the MySQL C API maps onto underlying server commands.">
<colgroup>
<col style="width: 50%"/>
<col style="width: 50%"/>
</colgroup>
<thead>
<tr>
<th>
C API Function
</th>
<th>
Corresponding Server Command
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="ulink" href="/doc/c-api/8.4/en/mysql-stmt-prepare.html" target="_top">
<code class="literal">
mysql_stmt_prepare()
</code>
</a>
</td>
<td>
<code class="literal">
COM_STMT_PREPARE
</code>
</td>
</tr>
<tr>
<td>
<a class="ulink" href="/doc/c-api/8.4/en/mysql-stmt-execute.html" target="_top">
<code class="literal">
mysql_stmt_execute()
</code>
</a>
</td>
<td>
<code class="literal">
COM_STMT_EXECUTE
</code>
</td>
</tr>
<tr>
<td>
<a class="ulink" href="/doc/c-api/8.4/en/mysql-stmt-close.html" target="_top">
<code class="literal">
mysql_stmt_close()
</code>
</a>
</td>
<td>
<code class="literal">
COM_STMT_CLOSE
</code>
</td>
</tr>
</tbody>
</table>
</div>
</li>
<li class="listitem">
<p>
The text protocol. This is accessed using SQL statements
and maps onto underlying server commands as shown in the
following table.
</p>
<div class="informaltable">
<table summary="How the text protocol accessed using SQL statements maps onto underlying server commands.">
<colgroup>
<col style="width: 50%"/>
<col style="width: 50%"/>
</colgroup>
<thead>
<tr>
<th>
SQL Statement
</th>
<th>
Corresponding Server Command
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="prepare.html" title="15.5.1 PREPARE Statement">
<code class="literal">
PREPARE
</code>
</a>
</td>
<td>
<code class="literal">
SQLCOM_PREPARE
</code>
</td>
</tr>
<tr>
<td>
<a class="link" href="execute.html" title="15.5.2 EXECUTE Statement">
<code class="literal">
EXECUTE
</code>
</a>
</td>
<td>
<code class="literal">
SQLCOM_EXECUTE
</code>
</td>
</tr>
<tr>
<td>
<a class="link" href="deallocate-prepare.html" title="15.5.3 DEALLOCATE PREPARE Statement">
<code class="literal">
DEALLOCATE PREPARE
</code>
</a>
,
<a class="link" href="deallocate-prepare.html" title="15.5.3 DEALLOCATE PREPARE Statement">
<code class="literal">
DROP
PREPARE
</code>
</a>
</td>
<td>
<code class="literal">
SQLCOM_DEALLOCATE PREPARE
</code>
</td>
</tr>
</tbody>
</table>
</div>
</li>
</ul>
</div>
<p>
Performance Schema prepared statement instrumentation covers
both protocols. The following discussion refers to the server
commands rather than the C API functions or SQL statements.
</p>
<p>
Information about prepared statements is available in the
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table. This table enables inspection of prepared statements
used in the server and provides aggregated statistics about
them. To control the size of this table, set the
<a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_max_prepared_statements_instances">
<code class="literal">
performance_schema_max_prepared_statements_instances
</code>
</a>
system variable at server startup.
</p>
<p>
Collection of prepared statement information depends on the
statement instruments shown in the following table. These
instruments are enabled by default. To modify them, update the
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
table.
</p>
<div class="informaltable">
<table summary="Collection of prepared statement information depends on the statement instruments shown in this table.">
<colgroup>
<col style="width: 50%"/>
<col style="width: 50%"/>
</colgroup>
<thead>
<tr>
<th>
Instrument
</th>
<th>
Server Command
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="literal">
statement/com/Prepare
</code>
</td>
<td>
<code class="literal">
COM_STMT_PREPARE
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
statement/com/Execute
</code>
</td>
<td>
<code class="literal">
COM_STMT_EXECUTE
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
statement/sql/prepare_sql
</code>
</td>
<td>
<code class="literal">
SQLCOM_PREPARE
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
statement/sql/execute_sql
</code>
</td>
<td>
<code class="literal">
SQLCOM_EXECUTE
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
The Performance Schema manages the contents of the
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Statement preparation
</p>
<p>
A
<code class="literal">
COM_STMT_PREPARE
</code>
or
<code class="literal">
SQLCOM_PREPARE
</code>
command creates a
prepared statement in the server. If the statement is
successfully instrumented, a new row is added to the
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table. If the statement cannot be instrumented,
<a class="link" href="performance-schema-status-variables.html#statvar_Performance_schema_prepared_statements_lost">
<code class="literal">
Performance_schema_prepared_statements_lost
</code>
</a>
status variable is incremented.
</p>
</li>
<li class="listitem">
<p>
Prepared statement execution
</p>
<p>
Execution of a
<code class="literal">
COM_STMT_EXECUTE
</code>
or
<code class="literal">
SQLCOM_PREPARE
</code>
command for an
instrumented prepared statement instance updates the
corresponding
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table row.
</p>
</li>
<li class="listitem">
<p>
Prepared statement deallocation
</p>
<p>
Execution of a
<code class="literal">
COM_STMT_CLOSE
</code>
or
<code class="literal">
SQLCOM_DEALLOCATE_PREPARE
</code>
command for
an instrumented prepared statement instance removes the
corresponding
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table row. To avoid resource leaks, removal occurs even if
the prepared statement instruments described previously
are disabled.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table has these columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
OBJECT_INSTANCE_BEGIN
</code>
</p>
<p>
The address in memory of the instrumented prepared
statement.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
STATEMENT_ID
</code>
</p>
<p>
The internal statement ID assigned by the server. The text
and binary protocols both use statement IDs.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
STATEMENT_NAME
</code>
</p>
<p>
For the binary protocol, this column is
<code class="literal">
NULL
</code>
. For the text protocol, this
column is the external statement name assigned by the
user. For example, for the following SQL statement, the
name of the prepared statement is
<code class="literal">
stmt
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa23577929"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">PREPARE</span> stmt <span class="token keyword">FROM</span> <span class="token string">'SELECT 1'</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
SQL_TEXT
</code>
</p>
<p>
The prepared statement text, with
<code class="literal">
?
</code>
placeholder markers.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
OWNER_THREAD_ID
</code>
,
<code class="literal">
OWNER_EVENT_ID
</code>
</p>
<p>
These columns indicate the event that created the prepared
statement.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
OWNER_OBJECT_TYPE
</code>
,
<code class="literal">
OWNER_OBJECT_SCHEMA
</code>
,
<code class="literal">
OWNER_OBJECT_NAME
</code>
</p>
<p>
For a prepared statement created by a client session,
these columns are
<code class="literal">
NULL
</code>
. For a prepared
statement created by a stored program, these columns point
to the stored program. A typical user error is forgetting
to deallocate prepared statements. These columns can be
used to find stored programs that leak prepared
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa15995294"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span>
OWNER_OBJECT_TYPE<span class="token punctuation">,</span> OWNER_OBJECT_SCHEMA<span class="token punctuation">,</span> OWNER_OBJECT_NAME<span class="token punctuation">,</span>
STATEMENT_NAME<span class="token punctuation">,</span> SQL_TEXT
<span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>prepared_statements_instances
<span class="token keyword">WHERE</span> OWNER_OBJECT_TYPE <span class="token operator">IS</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
The query execution engine. The value is either
<code class="literal">
PRIMARY
</code>
or
<code class="literal">
SECONDARY
</code>
. For use with HeatWave Service and
HeatWave, where the
<code class="literal">
PRIMARY
</code>
engine is
<code class="literal">
InnoDB
</code>
and the
<code class="literal">
SECONDARY
</code>
engine is HeatWave
(
<code class="literal">
RAPID
</code>
). For MySQL Community Edition Server, MySQL Enterprise Edition Server
(on-premise), and HeatWave Service without HeatWave, the value is
always
<code class="literal">
PRIMARY
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TIMER_PREPARE
</code>
</p>
<p>
The time spent executing the statement preparation itself.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
COUNT_REPREPARE
</code>
</p>
<p>
The number of times the statement was reprepared
internally (see
<a class="xref" href="statement-caching.html" title="10.10.3 Caching of Prepared Statements and Stored Programs">
Section 10.10.3, “Caching of Prepared Statements and Stored Programs”
</a>
).
Timing statistics for repreparation are not available
because it is counted as part of statement execution, not
as a separate operation.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
COUNT_EXECUTE
</code>
,
<code class="literal">
SUM_TIMER_EXECUTE
</code>
,
<code class="literal">
MIN_TIMER_EXECUTE
</code>
,
<code class="literal">
AVG_TIMER_EXECUTE
</code>
,
<code class="literal">
MAX_TIMER_EXECUTE
</code>
</p>
<p>
Aggregated statistics for executions of the prepared
statement.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
SUM_
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
</p>
<p>
The remaining
<code class="literal">
SUM_
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
columns are the same as for the statement summary tables
(see
<a class="xref" href="performance-schema-statement-summary-tables.html" title="29.12.20.3 Statement Summary Tables">
Section 29.12.20.3, “Statement Summary Tables”
</a>
).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MAX_CONTROLLED_MEMORY
</code>
</p>
<p>
Reports the maximum amount of controlled memory used by a
prepared statement during execution.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MAX_TOTAL_MEMORY
</code>
</p>
<p>
Reports the maximum amount of memory used by a prepared
statement during execution.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table has these indexes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Primary key on (
<code class="literal">
OBJECT_INSTANCE_BEGIN
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
STATEMENT_ID
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
STATEMENT_NAME
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
OWNER_THREAD_ID
</code>
,
<code class="literal">
OWNER_EVENT_ID
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
OWNER_OBJECT_TYPE
</code>
,
<code class="literal">
OWNER_OBJECT_SCHEMA
</code>
,
<code class="literal">
OWNER_OBJECT_NAME
</code>
)
</p>
</li>
</ul>
</div>
<p>
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
resets the
statistics columns of the
<a class="link" href="performance-schema-prepared-statements-instances-table.html" title="29.12.6.4 The prepared_statements_instances Table">
<code class="literal">
prepared_statements_instances
</code>
</a>
table.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/keyring-oci-component.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="keyring-oci-component">
</a>
8.4.4.9 Using the Oracle Cloud Infrastructure Vault Keyring Component
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045240117632">
</a>
<a class="indexterm" name="idm46045240116624">
</a>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The Oracle Cloud Infrastructure Vault keyring component is included in MySQL Enterprise Edition, a
commercial product. To learn more about commercial products,
see
<a class="ulink" href="https://www.mysql.com/products/" target="_blank">
https://www.mysql.com/products/
</a>
.
</p>
</div>
<p>
<code class="literal">
component_keyring_oci
</code>
is part of the
component infrastructure that communicates with Oracle Cloud Infrastructure Vault for
back end storage. No key information is permanently stored in
MySQL server local storage. All keys are stored in Oracle Cloud Infrastructure Vault,
making this component well suited for Oracle Cloud Infrastructure MySQL customers for
management of their MySQL Enterprise Edition keys.
</p>
<p>
MySQL Keyring began transitioning from plugins to use the
component infrastructure. The introduction of
<code class="literal">
component_keyring_oci
</code>
is a continuation of
that effort. For more information, see
<a class="link" href="keyring-component-plugin-comparison.html" title="8.4.4.1 Keyring Components Versus Keyring Plugins">
Keyring
Components Versus Keyring Plugins
</a>
.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Only one keyring component or plugin should be enabled at a
time. Enabling multiple keyring components or plugins is
unsupported and results may not be as anticipated.
</p>
</div>
<p>
To use
<code class="literal">
component_keyring_oci
</code>
for keystore
management, you must:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Write a manifest that tells the server to load
<code class="literal">
component_keyring_oci
</code>
, as described in
<a class="xref" href="keyring-component-installation.html" title="8.4.4.2 Keyring Component Installation">
Section 8.4.4.2, “Keyring Component Installation”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Write a configuration file for
<code class="literal">
component_keyring_oci
</code>
, as described here.
</p>
</li>
</ol>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="keyring-oci-component.html#keyring-oci-component-configure" title="Configuration Notes">
Configuration Notes
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="keyring-oci-component.html#keyring-oci-component-verify" title="Verify the Component Installation">
Verify the Component Installation
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="keyring-oci-component.html#keyring-oci-component-usage" title="Vault Keyring Component Usage">
Vault Keyring Component Usage
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="keyring-oci-component-configure">
</a>
Configuration Notes
</h5>
</div>
</div>
</div>
<p>
When it initializes,
<code class="literal">
component_keyring_oci
</code>
reads either a global configuration file, or a global
configuration file paired with a local configuration file:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The component attempts to read its global configuration
file from the directory where the component library file
is installed (that is, the server plugin directory).
</p>
</li>
<li class="listitem">
<p>
If the global configuration file indicates use of a local
configuration file, the component attempts to read its
local configuration file from the data directory.
</p>
</li>
<li class="listitem">
<p>
Although global and local configuration files are located
in different directories, the file name is
<code class="filename">
component_keyring_oci.cnf
</code>
in both
locations.
</p>
</li>
<li class="listitem">
<p>
It is an error for no configuration file to exist.
<code class="literal">
component_keyring_oci
</code>
cannot initialize
without a valid configuration.
</p>
</li>
</ul>
</div>
<p>
Local configuration files permit setting up multiple server
instances to use
<code class="literal">
component_keyring_oci
</code>
,
such that component configuration for each server instance is
specific to a given data directory instance. This enables the
same keyring component to be used with a distinct Oracle Cloud Infrastructure Vault
for each instance.
</p>
<a class="indexterm" name="idm46045240089680">
</a>
<p>
You are assumed to be familiar with Oracle Cloud Infrastructure concepts, but the
following documentation may be helpful when setting up
resources to be used by
<code class="literal">
component_keyring_oci
</code>
:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/iaas/Content/KeyManagement/Concepts/keyoverview.htm" target="_blank">
Overview
of Vault
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/apisigningkey.htm" target="_blank">
Required
Keys and OCIDs
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingkeys.htm" target="_blank">
Managing
Keys
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/Identity/Tasks/managingcompartments.htm" target="_blank">
Managing
Compartments
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingsecrets.htm" target="_blank">
Managing
Secrets
</a>
</p>
</li>
</ul>
</div>
<p>
<code class="literal">
component_keyring_oci
</code>
configuration files
have these properties:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
A configuration file must be in valid JSON format.
</p>
</li>
<li class="listitem">
<p>
A configuration file permits these configuration items:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
<code class="literal">
"read_local_config"
</code>
: This item is
permitted only in the global configuration file. If
the item is not present, the component uses only the
global configuration file. If the item is present, its
value is
<code class="literal">
true
</code>
or
<code class="literal">
false
</code>
, indicating whether the
component should read configuration information from
the local configuration file.
</p>
<p>
If the
<code class="literal">
"read_local_config"
</code>
item is
present in the global configuration file along with
other items, the component checks the
<code class="literal">
"read_local_config"
</code>
item value
first:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: square; ">
<li class="listitem">
<p>
If the value is
<code class="literal">
false
</code>
, the
component processes the other items in the global
configuration file and ignores the local
configuration file.
</p>
</li>
<li class="listitem">
<p>
If the value is
<code class="literal">
true
</code>
, the
component ignores the other items in the global
configuration file and attempts to read the local
configuration file.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
“user”
</code>
: The OCID of the Oracle Cloud Infrastructure
user that
<code class="literal">
component_keyring_oci
</code>
uses for connections. Prior to using
<code class="literal">
component_keyring_oci
</code>
, the user
account must exist and be granted access to use the
configured Oracle Cloud Infrastructure tenancy, compartment, and vault
resources. To obtain the user OCID from the Console,
use the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/apisigningkey.htm" target="_blank">
Required
Keys and OCIDs
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“tenancy”
</code>
: The OCID of the
Oracle Cloud Infrastructure tenancy that
<code class="literal">
component_keyring_oci
</code>
uses as the
location of the MySQL compartment. Prior to using
<code class="literal">
component_keyring_oci
</code>
, you must
create a tenancy if it does not exist. To obtain the
tenancy OCID from the Console, use the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/apisigningkey.htm" target="_blank">
Required
Keys and OCIDs
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“compartment”
</code>
: The OCID of the
tenancy compartment that
<code class="literal">
component_keyring_oci
</code>
uses as the
location of the MySQL keys. Prior to using
<code class="literal">
component_keyring_oci
</code>
, you must
create a MySQL compartment or subcompartment if it
does not exist. This compartment should contain no
vault keys or vault secrets. It should not be used by
systems other than MySQL Keyring. For information
about managing compartments and obtaining the OCID,
see
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/Identity/Tasks/managingcompartments.htm" target="_blank">
Managing
Compartments
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“virtual_vault”
</code>
: The OCID of
the Oracle Cloud Infrastructure Vault that
<code class="literal">
component_keyring_oci
</code>
uses for
encryption operations. Prior to using
<code class="literal">
component_keyring_oci
</code>
, you must
create a new vault in the MySQL compartment if it does
not exist. (Alternatively, you can reuse an existing
vault that is in a parent compartment of the MySQL
compartment.) Compartment users can see and use only
the keys in their respective compartments. For
information about creating a vault and obtaining the
vault OCID, see
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“encryption_endpoint”
</code>
: The
endpoint of the Oracle Cloud Infrastructure encryption server that
<code class="literal">
component_keyring_oci
</code>
uses for
generating encrypted or encoded information
(ciphertext) for new keys. The encryption endpoint is
vault specific and Oracle Cloud Infrastructure assigns it at vault-creation
time. To obtain the endpoint OCID, view the
configuration details for your keyring_oci vault,
using the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
"management_endpoint"
</code>
: The endpoint
of the Oracle Cloud Infrastructure key management server that
<code class="literal">
component_keyring_oci
</code>
uses for
listing existing keys. The key management endpoint is
vault specific and Oracle Cloud Infrastructure assigns it at vault-creation
time. To obtain the endpoint OCID, view the
configuration details for your keyring_oci vault,
using the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“vaults_endpoint”
</code>
: The endpoint
of the Oracle Cloud Infrastructure vaults server that
<code class="literal">
component_keyring_oci
</code>
uses for
obtaining the value of secrets. The vaults endpoint is
vault specific and Oracle Cloud Infrastructure assigns it at vault-creation
time. To obtain the endpoint OCID, view the
configuration details for your keyring_oci vault,
using the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“secrets_endpoint”
</code>
: The
endpoint of the Oracle Cloud Infrastructure secrets server that
<code class="literal">
component_keyring_oci
</code>
uses for
listing, creating, and retiring secrets. The secrets
endpoint is vault specific and Oracle Cloud Infrastructure assigns it at
vault-creation time. To obtain the endpoint OCID, view
the configuration details for your keyring_oci vault,
using the instructions at
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingvaults.htm" target="_blank">
Managing
Vaults
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“master_key”
</code>
: The OCID of the
Oracle Cloud Infrastructure master encryption key that
<code class="literal">
component_keyring_oci
</code>
uses for
encryption of secrets. Prior to using
<code class="literal">
component_keyring_oci
</code>
, you must
create a cryptographic key for the Oracle Cloud Infrastructure compartment
if it does not exist. Provide a MySQL-specific name
for the generated key and do not use it for other
purposes. For information about key creation, see
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/KeyManagement/Tasks/managingkeys.htm" target="_blank">
Managing
Keys
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“key_file”
</code>
: The path name of
the file containing the RSA private key that
<code class="literal">
component_keyring_oci
</code>
uses for
Oracle Cloud Infrastructure authentication. You must also upload the
corresponding RSA public key using the Console. The
Console displays the key fingerprint value, which you
can use to set the
<code class="literal">
"key_fingerprint"
</code>
value. For
information about generating and uploading API keys,
see
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/apisigningkey.htm" target="_blank">
Required
Keys and OCIDs
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“key_fingerprint”
</code>
: The
fingerprint of the RSA private key that
<code class="literal">
component_keyring_oci
</code>
uses for
Oracle Cloud Infrastructure authentication. To obtain the key fingerprint
while creating the API keys, execute this command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa60373711"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">openssl rsa <span class="token property">-pubout</span> <span class="token property">-outform</span> DER <span class="token property">-in</span> ~/<span class="token punctuation">.</span>oci/oci_api_key<span class="token punctuation">.</span>pem | openssl md5 <span class="token property">-c</span></code></pre>
</div>
<p>
Alternatively, obtain the fingerprint from the
Console, which automatically displays the fingerprint
when you upload the RSA public key. For information
about obtaining key fingerprints, see
<a class="ulink" href="https://docs.cloud.oracle.com/en-us/iaas/Content/API/Concepts/apisigningkey.htm" target="_blank">
Required
Keys and OCIDs
</a>
.
</p>
<p>
This value is mandatory.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
“ca_certificate”
</code>
: The path name
of the CA certificate bundle file that
<code class="literal">
component_keyring_oci
</code>
component
uses for Oracle Cloud Infrastructure certificate verification. The file
contains one or more certificates for peer
verification. If no file is specified, the default CA
bundle installed on the system is used. If the value
is set to
<code class="literal">
disabled
</code>
(case-sensitive),
<code class="literal">
component_keyring_oci
</code>
performs no
certificate verification.
</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
<p>
Given the preceding configuration file properties, to
configure
<code class="literal">
component_keyring_oci
</code>
, create a
global configuration file named
<code class="filename">
component_keyring_oci.cnf
</code>
in the
directory where the
<code class="literal">
component_keyring_oci
</code>
library file is installed, and optionally create a local
configuration file, also named
<code class="filename">
component_keyring_oci.cnf
</code>
, in the data
directory.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="keyring-oci-component-verify">
</a>
Verify the Component Installation
</h5>
</div>
</div>
</div>
<p>
After performing any component-specific configuration, start
the server. Verify component installation by examining the
Performance Schema
<a class="link" href="performance-schema-keyring-component-status-table.html" title="29.12.18.1 The keyring_component_status Table">
<code class="literal">
keyring_component_status
</code>
</a>
table:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa27381260"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>keyring_component_status<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> STATUS_KEY <span class="token punctuation">|</span> STATUS_VALUE <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Component_name <span class="token punctuation">|</span> component_keyring_oci <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Author <span class="token punctuation">|</span> Oracle Corporation <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> License <span class="token punctuation">|</span> PROPRIETARY <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Implementation_name <span class="token punctuation">|</span> component_keyring_oci <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Version <span class="token punctuation">|</span> 1.0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Component_status <span class="token punctuation">|</span> Active <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> user <span class="token punctuation">|</span> ocid1.user.oc1..aaaaaaaasqly<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> tenancy <span class="token punctuation">|</span> ocid1.tenancy.oc1..aaaaaaaai<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> compartment <span class="token punctuation">|</span> ocid1.compartment.oc1..aaaaaaaah2swh<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> virtual_vault <span class="token punctuation">|</span> ocid1.vault.oc1.iad.bbo5xyzkaaeuk.abuwcljtmvxp4r<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> master_key <span class="token punctuation">|</span> ocid1.key.oc1.iad.bbo5xyzkaaeuk.abuwcljrbsrewgap<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> encryption_endpoint <span class="token punctuation">|</span> bbo5xyzkaaeuk<span class="token punctuation">-</span>crypto.kms.us<span class="token punctuation">-</span><...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> management_endpoint <span class="token punctuation">|</span> bbo5xyzkaaeuk<span class="token punctuation">-</span>management.kms.us<span class="token punctuation">-</span><...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> vaults_endpoint <span class="token punctuation">|</span> vaults.us<span class="token punctuation">-</span><...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> secrets_endpoint <span class="token punctuation">|</span> secrets.vaults.us<span class="token punctuation">-</span><...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> key_file <span class="token punctuation">|</span> ~/.oci/oci_api_key.pem <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> key_fingerprint <span class="token punctuation">|</span> ca:7c:e1:fa:86:b6:40:af:39:d6<...> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> ca_certificate <span class="token punctuation">|</span> disabled <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
A
<code class="literal">
Component_status
</code>
value of
<code class="literal">
Active
</code>
indicates that the component
initialized successfully.
</p>
<p>
If the component cannot be loaded, server startup fails. Check
the server error log for diagnostic messages. If the component
loads but fails to initialize due to configuration problems,
the server starts but the
<code class="literal">
Component_status
</code>
value is
<code class="literal">
Disabled
</code>
. Check the server error
log, correct the configuration issues, and use the
<a class="link" href="alter-instance.html#alter-instance-reload-keyring">
<code class="literal">
ALTER INSTANCE RELOAD KEYRING
</code>
</a>
statement to reload the configuration.
</p>
<p>
It is possible to query MySQL server for the list of existing
keys. To see which keys exist, examine the Performance Schema
<a class="link" href="performance-schema-keyring-keys-table.html" title="29.12.18.2 The keyring_keys table">
<code class="literal">
keyring_keys
</code>
</a>
table.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa92794516"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>keyring_keys<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> KEY_ID <span class="token punctuation">|</span> KEY_OWNER <span class="token punctuation">|</span> BACKEND_KEY_ID <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> audit_log<span class="token punctuation">-</span>20210322T130749<span class="token punctuation">-</span>1 <span class="token punctuation">|</span> <span class="token punctuation">|</span> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> MyKey <span class="token punctuation">|</span> me@localhost <span class="token punctuation">|</span> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> YourKey <span class="token punctuation">|</span> me@localhost <span class="token punctuation">|</span> <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="keyring-oci-component-usage">
</a>
Vault Keyring Component Usage
</h5>
</div>
</div>
</div>
<p>
<code class="literal">
component_keyring_oci
</code>
supports the
functions that comprise the standard MySQL Keyring service
interface. Keyring operations performed by those functions are
accessible in SQL statements as described in
<a class="xref" href="keyring-functions-general-purpose.html" title="8.4.4.12 General-Purpose Keyring Key-Management Functions">
Section 8.4.4.12, “General-Purpose Keyring Key-Management Functions”
</a>
.
</p>
<p>
Example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa67182112"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> keyring_key_generate<span class="token punctuation">(</span><span class="token string">'MyKey'</span><span class="token punctuation">,</span> <span class="token string">'AES'</span><span class="token punctuation">,</span> <span class="token number">32</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> keyring_key_remove<span class="token punctuation">(</span><span class="token string">'MyKey'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
For information about the characteristics of key values
permitted by
<code class="literal">
component_keyring_oci
</code>
, see
<a class="xref" href="keyring-key-types.html" title="8.4.4.10 Supported Keyring Key Types and Lengths">
Section 8.4.4.10, “Supported Keyring Key Types and Lengths”
</a>
.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysqlbinlog-row-events.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysqlbinlog-row-events">
</a>
6.6.9.2 mysqlbinlog Row Event Display
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045303509664">
</a>
<p>
The following examples illustrate how
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
displays row events that specify
data modifications. These correspond to events with the
<code class="literal">
WRITE_ROWS_EVENT
</code>
,
<code class="literal">
UPDATE_ROWS_EVENT
</code>
, and
<code class="literal">
DELETE_ROWS_EVENT
</code>
type codes. The
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_base64-output">
<code class="option">
--base64-output=DECODE-ROWS
</code>
</a>
and
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_verbose">
<code class="option">
--verbose
</code>
</a>
options may be
used to affect row event output.
</p>
<p>
Suppose that the server is using row-based binary logging and
that you execute the following sequence of statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa12226755"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t
<span class="token punctuation">(</span>
id <span class="token datatype">INT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
<span class="token keyword">name</span> <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
<span class="token datatype">date</span> <span class="token datatype">DATE</span> <span class="token boolean">NULL</span>
<span class="token punctuation">)</span> <span class="token keyword">ENGINE</span> <span class="token operator">=</span> InnoDB<span class="token punctuation">;</span>
<span class="token keyword">START</span> <span class="token keyword">TRANSACTION</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token string">'apple'</span><span class="token punctuation">,</span> <span class="token boolean">NULL</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">UPDATE</span> t <span class="token keyword">SET</span> <span class="token keyword">name</span> <span class="token operator">=</span> <span class="token string">'pear'</span><span class="token punctuation">,</span> <span class="token datatype">date</span> <span class="token operator">=</span> <span class="token string">'2009-01-01'</span> <span class="token keyword">WHERE</span> id <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token keyword">DELETE</span> <span class="token keyword">FROM</span> t <span class="token keyword">WHERE</span> id <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token keyword">COMMIT</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
By default,
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
displays row events
encoded as base-64 strings using
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements. Omitting
extraneous lines, the output for the row events produced by the
preceding statement sequence looks like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa9808264"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqlbinlog</span> <em class="replaceable">log_file</em>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 218</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ<span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">=</span></span>
'/*!*/<span class="token punctuation">;</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 302</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 400</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span></code></pre>
</div>
<p>
To see the row events as comments in the form of
<span class="quote">
“
<span class="quote">
pseudo-SQL
</span>
”
</span>
statements, run
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
with the
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_verbose">
<code class="option">
--verbose
</code>
</a>
or
<code class="option">
-v
</code>
option. This output level also shows table
partition information where applicable. The output contains
lines beginning with
<code class="literal">
###
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa60465379"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqlbinlog</span> <span class="token property">-v</span> <em class="replaceable">log_file</em>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 218</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ<span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">=</span></span>
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### INSERT INTO test.t</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='apple'</span>
<span class="token comment" spellcheck="true">### @3=NULL</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 302</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### UPDATE test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='apple'</span>
<span class="token comment" spellcheck="true">### @3=NULL</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='pear'</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01'</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 400</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### DELETE FROM test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='pear'</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01'</span></code></pre>
</div>
<p>
Specify
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_verbose">
<code class="option">
--verbose
</code>
</a>
or
<code class="option">
-v
</code>
twice to also display data types and some
metadata for each column, and informational log events such as
row query log events if the
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_rows_query_log_events">
<code class="literal">
binlog_rows_query_log_events
</code>
</a>
system variable is set to
<code class="literal">
TRUE
</code>
. The output
contains an additional comment following each column change:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa29633186"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqlbinlog</span> <span class="token property">-vv</span> <em class="replaceable">log_file</em>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 218</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAANoAAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBcBAAAAKAAAAAIBAAAQABEAAAAAAAEAA//8AQAAAAVhcHBsZQ<span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">=</span></span>
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### INSERT INTO test.t</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1 /* INT meta=0 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 302</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAC4BAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBgBAAAANgAAAGQBAAAQABEAAAAAAAEAA////AEAAAAFYXBwbGX4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### UPDATE test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1 /* INT meta=0 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @2='apple' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @3=NULL /* VARSTRING(20) meta=0 nullable=1 is_null=1 */</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1 /* INT meta=0 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 400</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F</span>
BINLOG '
fAS3SBMBAAAALAAAAJABAAAAABEAAAAAAAAABHRlc3QAAXQAAwMPCgIUAAQ=
fAS3SBkBAAAAKgAAALoBAAAQABEAAAAAAAEAA//4AQAAAARwZWFyIbIP
'/*!*/<span class="token punctuation">;</span>
<span class="token comment" spellcheck="true">### DELETE FROM test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1 /* INT meta=0 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @2='pear' /* VARSTRING(20) meta=20 nullable=0 is_null=0 */</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01' /* DATE meta=0 nullable=1 is_null=0 */</span></code></pre>
</div>
<p>
You can tell
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
to suppress the
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements for row events
by using the
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_base64-output">
<code class="option">
--base64-output=DECODE-ROWS
</code>
</a>
option. This is similar to
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_base64-output">
<code class="option">
--base64-output=NEVER
</code>
</a>
but
does not exit with an error if a row event is found. The
combination of
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_base64-output">
<code class="option">
--base64-output=DECODE-ROWS
</code>
</a>
and
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_verbose">
<code class="option">
--verbose
</code>
</a>
provides a
convenient way to see row events only as SQL statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa40096769"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqlbinlog</span> <span class="token property">-v</span> <span class="token constant">--base64-output</span><span class="token attr-value"><span class="token punctuation">=</span>DECODE-ROWS</span> <em class="replaceable">log_file</em>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 218</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 258 Write_rows: table id 17 flags: STMT_END_F</span>
<span class="token comment" spellcheck="true">### INSERT INTO test.t</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='apple'</span>
<span class="token comment" spellcheck="true">### @3=NULL</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 302</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 356 Update_rows: table id 17 flags: STMT_END_F</span>
<span class="token comment" spellcheck="true">### UPDATE test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='apple'</span>
<span class="token comment" spellcheck="true">### @3=NULL</span>
<span class="token comment" spellcheck="true">### SET</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='pear'</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01'</span>
<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
<span class="token comment" spellcheck="true"># at 400</span>
<span class="token comment" spellcheck="true">#080828 15:03:08 server id 1 end_log_pos 442 Delete_rows: table id 17 flags: STMT_END_F</span>
<span class="token comment" spellcheck="true">### DELETE FROM test.t</span>
<span class="token comment" spellcheck="true">### WHERE</span>
<span class="token comment" spellcheck="true">### @1=1</span>
<span class="token comment" spellcheck="true">### @2='pear'</span>
<span class="token comment" spellcheck="true">### @3='2009:01:01'</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
You should not suppress
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements if you intend to re-execute
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
output.
</p>
</div>
<p>
The SQL statements produced by
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_verbose">
<code class="option">
--verbose
</code>
</a>
for row events are
much more readable than the corresponding
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements. However, they
do not correspond exactly to the original SQL statements that
generated the events. The following limitations apply:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The original column names are lost and replaced by
<code class="literal">
@
<em class="replaceable">
<code>
N
</code>
</em>
</code>
, where
<em class="replaceable">
<code>
N
</code>
</em>
is a column number.
</p>
</li>
<li class="listitem">
<p>
Character set information is not available in the binary
log, which affects string column display:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
There is no distinction made between corresponding
binary and nonbinary string types
(
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
BINARY
</code>
</a>
and
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
CHAR
</code>
</a>
,
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
VARBINARY
</code>
</a>
and
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
VARCHAR
</code>
</a>
,
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
BLOB
</code>
</a>
and
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
TEXT
</code>
</a>
). The output uses a
data type of
<code class="literal">
STRING
</code>
for fixed-length
strings and
<code class="literal">
VARSTRING
</code>
for
variable-length strings.
</p>
</li>
<li class="listitem">
<p>
For multibyte character sets, the maximum number of
bytes per character is not present in the binary log, so
the length for string types is displayed in bytes rather
than in characters. For example,
<code class="literal">
STRING(4)
</code>
is used as the data type
for values from either of these column types:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa54335817"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">)</span> <span class="token keyword">CHARACTER</span> <span class="token keyword">SET</span> latin1
<span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span> <span class="token keyword">CHARACTER</span> <span class="token keyword">SET</span> ucs2</code></pre>
</div>
</li>
<li class="listitem">
<p>
Due to the storage format for events of type
<code class="literal">
UPDATE_ROWS_EVENT
</code>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
statements are
displayed with the
<code class="literal">
WHERE
</code>
clause
preceding the
<code class="literal">
SET
</code>
clause.
</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
<p>
Proper interpretation of row events requires the information
from the format description event at the beginning of the binary
log. Because
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
does not know in
advance whether the rest of the log contains row events, by
default it displays the format description event using a
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statement in the initial
part of the output.
</p>
<p>
If the binary log is known not to contain any events requiring a
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statement (that is, no row
events), the
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_base64-output">
<code class="option">
--base64-output=NEVER
</code>
</a>
option
can be used to prevent this header from being written.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/backup-strategy-summary.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="backup-strategy-summary">
</a>
9.3.3 Backup Strategy Summary
</h3>
</div>
</div>
</div>
<p>
In case of an operating system crash or power failure,
<code class="literal">
InnoDB
</code>
itself does all the job of recovering
data. But to make sure that you can sleep well, observe the
following guidelines:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Always tun the MySQL server with binary logging enabled
(that is the default setting for MySQL 8.4).
If you have such safe media, this technique can also be good
for disk load balancing (which results in a performance
improvement).
</p>
</li>
<li class="listitem">
<p>
Make periodic full backups, using the
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
command shown earlier in
<a class="xref" href="backup-policy.html" title="9.3.1 Establishing a Backup Policy">
Section 9.3.1, “Establishing a Backup Policy”
</a>
, that makes an online,
nonblocking backup.
</p>
</li>
<li class="listitem">
<p>
Make periodic incremental backups by flushing the logs with
<a class="link" href="flush.html#flush-logs">
<code class="literal">
FLUSH LOGS
</code>
</a>
or
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin flush-logs
</strong>
</span>
</a>
.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-runtime-configuration.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="performance-schema-runtime-configuration">
</a>
29.4 Performance Schema Runtime Configuration
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="performance-schema-timing.html">
29.4.1 Performance Schema Event Timing
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-filtering.html">
29.4.2 Performance Schema Event Filtering
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-pre-filtering.html">
29.4.3 Event Pre-Filtering
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-instrument-filtering.html">
29.4.4 Pre-Filtering by Instrument
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-object-filtering.html">
29.4.5 Pre-Filtering by Object
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-thread-filtering.html">
29.4.6 Pre-Filtering by Thread
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-consumer-filtering.html">
29.4.7 Pre-Filtering by Consumer
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-consumer-configurations.html">
29.4.8 Example Consumer Configurations
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-filtering-names.html">
29.4.9 Naming Instruments or Consumers for Filtering Operations
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-instrumentation-checking.html">
29.4.10 Determining What Is Instrumented
</a>
</span>
</dt>
</dl>
</div>
<p>
Specific Performance Schema features can be enabled at runtime to
control which types of event collection occur.
</p>
<p>
Performance Schema setup tables contain information about
monitoring configuration:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa3495715"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">TABLE_NAME</span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">TABLES</span>
<span class="token keyword">WHERE</span> TABLE_SCHEMA <span class="token operator">=</span> <span class="token string">'performance_schema'</span>
<span class="token operator">AND</span> <span class="token keyword">TABLE_NAME</span> <span class="token operator">LIKE</span> <span class="token string">'setup%'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> TABLE_NAME <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> setup_actors <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> setup_consumers <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> setup_instruments <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> setup_objects <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> setup_threads <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
You can examine the contents of these tables to obtain information
about Performance Schema monitoring characteristics. If you have
the
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
privilege, you can
change Performance Schema operation by modifying setup tables to
affect how monitoring occurs. For additional details about these
tables, see
<a class="xref" href="performance-schema-setup-tables.html" title="29.12.2 Performance Schema Setup Tables">
Section 29.12.2, “Performance Schema Setup Tables”
</a>
.
</p>
<p>
The
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
and
<a class="link" href="performance-schema-setup-consumers-table.html" title="29.12.2.2 The setup_consumers Table">
<code class="literal">
setup_consumers
</code>
</a>
tables list the
instruments for which events can be collected and the types of
consumers for which event information actually is collected,
respectively. Other setup tables enable further modification of
the monitoring configuration.
<a class="xref" href="performance-schema-filtering.html" title="29.4.2 Performance Schema Event Filtering">
Section 29.4.2, “Performance Schema Event Filtering”
</a>
, discusses how you
can modify these tables to affect event collection.
</p>
<p>
If there are Performance Schema configuration changes that must be
made at runtime using SQL statements and you would like these
changes to take effect each time the server starts, put the
statements in a file and start the server with the
<a class="link" href="server-system-variables.html#sysvar_init_file">
<code class="literal">
init_file
</code>
</a>
system variable set to
name the file. This strategy can also be useful if you have
multiple monitoring configurations, each tailored to produce a
different kind of monitoring, such as casual server health
monitoring, incident investigation, application behavior
troubleshooting, and so forth. Put the statements for each
monitoring configuration into their own file and specify the
appropriate file as the
<a class="link" href="server-system-variables.html#sysvar_init_file">
<code class="literal">
init_file
</code>
</a>
value when you start the server.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/events-overview.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="events-overview">
</a>
27.4.1 Event Scheduler Overview
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045082244944">
</a>
<p>
MySQL Events are tasks that run according to a schedule.
Therefore, we sometimes refer to them as
<span class="emphasis">
<em>
scheduled
</em>
</span>
events. When you create an event,
you are creating a named database object containing one or more
SQL statements to be executed at one or more regular intervals,
beginning and ending at a specific date and time. Conceptually,
this is similar to the idea of the Unix
<code class="literal">
crontab
</code>
(also known as a
<span class="quote">
“
<span class="quote">
cron job
</span>
”
</span>
) or the Windows Task
Scheduler.
</p>
<p>
Scheduled tasks of this type are also sometimes known as
<span class="quote">
“
<span class="quote">
temporal triggers
</span>
”
</span>
, implying that these are objects
that are triggered by the passage of time. While this is
essentially correct, we prefer to use the term
<span class="emphasis">
<em>
events
</em>
</span>
to avoid confusion with triggers of
the type discussed in
<a class="xref" href="triggers.html" title="27.3 Using Triggers">
Section 27.3, “Using Triggers”
</a>
. Events should
more specifically not be confused with
<span class="quote">
“
<span class="quote">
temporary
triggers
</span>
”
</span>
. Whereas a trigger is a database object whose
statements are executed in response to a specific type of event
that occurs on a given table, a (scheduled) event is an object
whose statements are executed in response to the passage of a
specified time interval.
</p>
<p>
While there is no provision in the SQL Standard for event
scheduling, there are precedents in other database systems, and
you may notice some similarities between these implementations and
that found in the MySQL Server.
</p>
<p>
MySQL Events have the following major features and properties:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
In MySQL, an event is uniquely identified by its name and the
schema to which it is assigned.
</p>
</li>
<li class="listitem">
<p>
An event performs a specific action according to a schedule.
This action consists of an SQL statement, which can be a
compound statement in a
<a class="link" href="begin-end.html" title="15.6.1 BEGIN ... END Compound Statement">
<code class="literal">
BEGIN ...
END
</code>
</a>
block if desired (see
<a class="xref" href="sql-compound-statements.html" title="15.6 Compound Statement Syntax">
Section 15.6, “Compound Statement Syntax”
</a>
). An event's timing
can be either
<span class="firstterm">
one-time
</span>
or
<span class="firstterm">
recurrent
</span>
. A one-time
event executes one time only. A recurrent event repeats its
action at a regular interval, and the schedule for a recurring
event can be assigned a specific start day and time, end day
and time, both, or neither. (By default, a recurring event's
schedule begins as soon as it is created, and continues
indefinitely, until it is disabled or dropped.)
</p>
<p>
If a repeating event does not terminate within its scheduling
interval, the result may be multiple instances of the event
executing simultaneously. If this is undesirable, you should
institute a mechanism to prevent simultaneous instances. For
example, you could use the
<a class="link" href="locking-functions.html#function_get-lock">
<code class="literal">
GET_LOCK()
</code>
</a>
function, or row or
table locking.
</p>
</li>
<li class="listitem">
<p>
Users can create, modify, and drop scheduled events using SQL
statements intended for these purposes. Syntactically invalid
event creation and modification statements fail with an
appropriate error message.
<span class="emphasis">
<em>
A user may include
statements in an event's action which require privileges that
the user does not actually have
</em>
</span>
. The event creation
or modification statement succeeds but the event's action
fails. See
<a class="xref" href="events-privileges.html" title="27.4.6 The Event Scheduler and MySQL Privileges">
Section 27.4.6, “The Event Scheduler and MySQL Privileges”
</a>
for details.
</p>
</li>
<li class="listitem">
<p>
Many of the properties of an event can be set or modified
using SQL statements. These properties include the event's
name, timing, persistence (that is, whether it is preserved
following the expiration of its schedule), status (enabled or
disabled), action to be performed, and the schema to which it
is assigned. See
<a class="xref" href="alter-event.html" title="15.1.3 ALTER EVENT Statement">
Section 15.1.3, “ALTER EVENT Statement”
</a>
.
</p>
<p>
The default definer of an event is the user who created the
event, unless the event has been altered, in which case the
definer is the user who issued the last
<a class="link" href="alter-event.html" title="15.1.3 ALTER EVENT Statement">
<code class="literal">
ALTER EVENT
</code>
</a>
statement affecting
that event. An event can be modified by any user having the
<a class="link" href="privileges-provided.html#priv_event">
<code class="literal">
EVENT
</code>
</a>
privilege on the database
for which the event is defined. See
<a class="xref" href="events-privileges.html" title="27.4.6 The Event Scheduler and MySQL Privileges">
Section 27.4.6, “The Event Scheduler and MySQL Privileges”
</a>
.
</p>
</li>
<li class="listitem">
<p>
An event's action statement may include most SQL statements
permitted within stored routines. For restrictions, see
<a class="xref" href="stored-program-restrictions.html" title="27.8 Restrictions on Stored Programs">
Section 27.8, “Restrictions on Stored Programs”
</a>
.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/firewall-elements.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="firewall-elements">
</a>
8.4.7.1 Elements of MySQL Enterprise Firewall
</h4>
</div>
</div>
</div>
<p>
MySQL Enterprise Firewall is based on a plugin library that includes these
elements:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
A server-side plugin named
<code class="literal">
MYSQL_FIREWALL
</code>
examines SQL statements before they execute and, based on
the registered firewall profiles, renders a decision whether
to execute or reject each statement.
</p>
</li>
<li class="listitem">
<p>
The
<code class="literal">
MYSQL_FIREWALL
</code>
plugin, along with
server-side plugins named
<code class="literal">
MYSQL_FIREWALL_USERS
</code>
and
<code class="literal">
MYSQL_FIREWALL_WHITELIST
</code>
implement
Performance Schema and
<code class="literal">
INFORMATION_SCHEMA
</code>
tables that provide views into the registered profiles.
</p>
</li>
<li class="listitem">
<p>
Profiles are cached in memory for better performance. Tables
in the firewall database provide backing storage of firewall
data for persistence of profiles across server restarts. The
firewall database can be the
<code class="literal">
mysql
</code>
system
database or a custom schema (see
<a class="xref" href="firewall-installation.html#firewall-install" title="Installing MySQL Enterprise Firewall">
Installing MySQL Enterprise Firewall
</a>
).
</p>
</li>
<li class="listitem">
<p>
Stored procedures perform tasks such as registering firewall
profiles, establishing their operational mode, and managing
transfer of firewall data between the cache and persistent
storage.
</p>
</li>
<li class="listitem">
<p>
Administrative functions provide an API for lower-level
tasks such as synchronizing the cache with persistent
storage.
</p>
</li>
<li class="listitem">
<p>
System variables enable firewall configuration and status
variables provide runtime operational information.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="privileges-provided.html#priv_firewall-admin">
<code class="literal">
FIREWALL_ADMIN
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_firewall-user">
<code class="literal">
FIREWALL_USER
</code>
</a>
privileges
enable users to administer firewall rules for any user, and
their own firewall rules, respectively.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="privileges-provided.html#priv_firewall-exempt">
<code class="literal">
FIREWALL_EXEMPT
</code>
</a>
privilege
exempts a user from firewall restrictions. This is useful,
for example, for any database administrator who configures
the firewall, to avoid the possibility of a misconfiguration
causing even the administrator to be locked out and unable
to execute statements.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/updating-sles-repo.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="updating-sles-repo">
</a>
3.10 Upgrading MySQL with the MySQL SLES Repository
</h2>
</div>
</div>
</div>
<a class="indexterm" name="idm46045325933328">
</a>
<a class="indexterm" name="idm46045325932288">
</a>
<p>
On the SUSE Linux Enterprise Server (SLES) platform, to perform an
in-place upgrade of MySQL and its components, use the MySQL SLES
repository. See
<a class="xref" href="linux-installation-sles-repo.html#linux-installation-sles-repo-upgrading" title="Upgrading MySQL with the MySQL SLES Repository">
Upgrading MySQL with the MySQL SLES Repository
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/backup-and-recovery.html | <div id="docs-body">
<div class="chapter">
<div class="titlepage">
<div>
<div>
<h1 class="title">
<a name="backup-and-recovery">
</a>
Chapter 9 Backup and Recovery
</h1>
</div>
</div>
</div>
<div class="toc">
<p>
<b>
Table of Contents
</b>
</p>
<dl class="toc">
<dt>
<span class="section">
<a href="backup-types.html">
9.1 Backup and Recovery Types
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="backup-methods.html">
9.2 Database Backup Methods
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="backup-strategy-example.html">
9.3 Example Backup and Recovery Strategy
</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="backup-policy.html">
9.3.1 Establishing a Backup Policy
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="recovery-from-backups.html">
9.3.2 Using Backups for Recovery
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="backup-strategy-summary.html">
9.3.3 Backup Strategy Summary
</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="using-mysqldump.html">
9.4 Using mysqldump for Backups
</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="mysqldump-sql-format.html">
9.4.1 Dumping Data in SQL Format with mysqldump
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="reloading-sql-format-dumps.html">
9.4.2 Reloading SQL-Format Backups
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="mysqldump-delimited-text.html">
9.4.3 Dumping Data in Delimited-Text Format with mysqldump
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="reloading-delimited-text-dumps.html">
9.4.4 Reloading Delimited-Text Format Backups
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="mysqldump-tips.html">
9.4.5 mysqldump Tips
</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="point-in-time-recovery.html">
9.5 Point-in-Time (Incremental) Recovery
</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="point-in-time-recovery-binlog.html">
9.5.1 Point-in-Time Recovery Using Binary Log
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="point-in-time-recovery-positions.html">
9.5.2 Point-in-Time Recovery Using Event Positions
</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="myisam-table-maintenance.html">
9.6 MyISAM Table Maintenance and Crash Recovery
</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="myisam-crash-recovery.html">
9.6.1 Using myisamchk for Crash Recovery
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="myisam-check.html">
9.6.2 How to Check MyISAM Tables for Errors
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="myisam-repair.html">
9.6.3 How to Repair MyISAM Tables
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="myisam-optimization.html">
9.6.4 MyISAM Table Optimization
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="myisam-maintenance-schedule.html">
9.6.5 Setting Up a MyISAM Table Maintenance Schedule
</a>
</span>
</dt>
</dl>
</dd>
</dl>
</div>
<a class="indexterm" name="idm46045231410352">
</a>
<a class="indexterm" name="idm46045231408864">
</a>
<p>
It is important to back up your databases so that you can recover
your data and be up and running again in case problems occur, such
as system crashes, hardware failures, or users deleting data by
mistake. Backups are also essential as a safeguard before upgrading
a MySQL installation, and they can be used to transfer a MySQL
installation to another system or to set up replica servers.
</p>
<p>
MySQL offers a variety of backup strategies from which you can
choose the methods that best suit the requirements for your
installation. This chapter discusses several backup and recovery
topics with which you should be familiar:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Types of backups: Logical versus physical, full versus
incremental, and so forth.
</p>
</li>
<li class="listitem">
<p>
Methods for creating backups.
</p>
</li>
<li class="listitem">
<p>
Recovery methods, including point-in-time recovery.
</p>
</li>
<li class="listitem">
<p>
Backup scheduling, compression, and encryption.
</p>
</li>
<li class="listitem">
<p>
Table maintenance, to enable recovery of corrupt tables.
</p>
</li>
</ul>
</div>
<h2>
<a name="idm46045231401648">
</a>
Additional Resources
</h2>
<p>
Resources related to backup or to maintaining data availability
include the following:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Customers of MySQL Enterprise Edition can use the MySQL Enterprise Backup product for backups. For an
overview of the MySQL Enterprise Backup product, see
<a class="xref" href="mysql-enterprise-backup.html" title="32.1 MySQL Enterprise Backup Overview">
Section 32.1, “MySQL Enterprise Backup Overview”
</a>
.
</p>
</li>
<li class="listitem">
<p>
A forum dedicated to backup issues is available at
<a class="ulink" href="https://forums.mysql.com/list.php?28" target="_blank">
https://forums.mysql.com/list.php?28
</a>
.
</p>
</li>
<li class="listitem">
<p>
Details for
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
can be found in
<a class="xref" href="programs.html" title="Chapter 6 MySQL Programs">
Chapter 6,
<i>
MySQL Programs
</i>
</a>
.
</p>
</li>
<li class="listitem">
<p>
The syntax of the SQL statements described here is given in
<a class="xref" href="sql-statements.html" title="Chapter 15 SQL Statements">
Chapter 15,
<i>
SQL Statements
</i>
</a>
.
</p>
</li>
<li class="listitem">
<p>
For additional information about
<code class="literal">
InnoDB
</code>
backup procedures, see
<a class="xref" href="innodb-backup.html" title="17.18.1 InnoDB Backup">
Section 17.18.1, “InnoDB Backup”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Replication enables you to maintain identical data on multiple
servers. This has several benefits, such as enabling client
query load to be distributed over servers, availability of data
even if a given server is taken offline or fails, and the
ability to make backups with no impact on the source by using a
replica. See
<a class="xref" href="replication.html" title="Chapter 19 Replication">
Chapter 19,
<i>
Replication
</i>
</a>
.
</p>
</li>
<li class="listitem">
<p>
MySQL InnoDB Cluster is a collection of products that work
together to provide a high availability solution. A group of
MySQL servers can be configured to create a cluster using
MySQL Shell. The cluster of servers has a single source, called
the primary, which acts as the read-write source. Multiple
secondary servers are replicas of the source. A minimum of three
servers are required to create a high availability cluster. A
client application is connected to the primary via MySQL Router. If
the primary fails, a secondary is automatically promoted to the
role of primary, and MySQL Router routes requests to the new
primary.
</p>
</li>
<li class="listitem">
<p>
NDB Cluster provides a high-availability, high-redundancy
version of MySQL adapted for the distributed computing
environment. See
<a class="xref" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
Chapter 25,
<i>
MySQL NDB Cluster 8.4
</i>
</a>
, which provides
information about MySQL NDB Cluster
8.4.0.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/information-schema-table-constraints-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="information-schema-table-constraints-table">
</a>
28.3.41 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045078265552">
</a>
<p>
The
<a class="link" href="information-schema-table-constraints-table.html" title="28.3.41 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table">
<code class="literal">
TABLE_CONSTRAINTS
</code>
</a>
table describes
which tables have constraints.
</p>
<p>
The
<a class="link" href="information-schema-table-constraints-table.html" title="28.3.41 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table">
<code class="literal">
TABLE_CONSTRAINTS
</code>
</a>
table has these
columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
CONSTRAINT_CATALOG
</code>
</p>
<p>
The name of the catalog to which the constraint belongs. This
value is always
<code class="literal">
def
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CONSTRAINT_SCHEMA
</code>
</p>
<p>
The name of the schema (database) to which the constraint
belongs.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CONSTRAINT_NAME
</code>
</p>
<p>
The name of the constraint.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TABLE_SCHEMA
</code>
</p>
<p>
The name of the schema (database) to which the table belongs.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TABLE_NAME
</code>
</p>
<p>
The name of the table.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CONSTRAINT_TYPE
</code>
</p>
<p>
The type of constraint. The value can be
<code class="literal">
UNIQUE
</code>
,
<code class="literal">
PRIMARY KEY
</code>
,
<code class="literal">
FOREIGN KEY
</code>
or
<code class="literal">
CHECK
</code>
.
This is a
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
CHAR
</code>
</a>
(not
<a class="link" href="enum.html" title="13.3.5 The ENUM Type">
<code class="literal">
ENUM
</code>
</a>
) column.
</p>
<p>
The
<code class="literal">
UNIQUE
</code>
and
<code class="literal">
PRIMARY
KEY
</code>
information is about the same as what you get
from the
<code class="literal">
Key_name
</code>
column in the output from
<a class="link" href="show-index.html" title="15.7.7.23 SHOW INDEX Statement">
<code class="literal">
SHOW INDEX
</code>
</a>
when the
<code class="literal">
Non_unique
</code>
column is
<code class="literal">
0
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
ENFORCED
</code>
</p>
<p>
For
<code class="literal">
CHECK
</code>
constraints, the value is
<code class="literal">
YES
</code>
or
<code class="literal">
NO
</code>
to indicate
whether the constraint is enforced. For other constraints, the
value is always
<code class="literal">
YES
</code>
.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/multifactor-authentication.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="multifactor-authentication">
</a>
8.2.18 Multifactor Authentication
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045248036864">
</a>
<a class="indexterm" name="idm46045248035376">
</a>
<a class="indexterm" name="idm46045248034288">
</a>
<a class="indexterm" name="idm46045248032816">
</a>
<a class="indexterm" name="idm46045248031296">
</a>
<a class="indexterm" name="idm46045248029776">
</a>
<a class="indexterm" name="idm46045248028256">
</a>
<a class="indexterm" name="idm46045248026736">
</a>
<a class="indexterm" name="idm46045248025216">
</a>
<a class="indexterm" name="idm46045248023696">
</a>
<a class="indexterm" name="idm46045248022176">
</a>
<a class="indexterm" name="idm46045248020656">
</a>
<a class="indexterm" name="idm46045248019568">
</a>
<p>
Authentication involves one party establishing its identity to the
satisfaction of a second party. Multifactor authentication (MFA)
is the use of multiple authentication values (or
<span class="quote">
“
<span class="quote">
factors
</span>
”
</span>
) during the authentication process. MFA
provides greater security than one-factor/single-factor
authentication (1FA/SFA), which uses only one authentication
method such as a password. MFA enables additional authentication
methods, such as authentication using multiple passwords, or
authentication using devices like smart cards, security keys, and
biometric readers.
</p>
<p>
MySQL includes support for multifactor authentication. This
capability includes forms of MFA that require up to three
authentication values. That is, MySQL account management supports
accounts that use 2FA or 3FA, in addition to the existing 1FA
support.
</p>
<p>
When a client attempts a connection to the MySQL server using a
single-factor account, the server invokes the authentication
plugin indicated by the account definition and accepts or rejects
the connection depending on whether the plugin reports success or
failure.
</p>
<p>
For an account that has multiple authentication factors, the
process is similar. The server invokes authentication plugins in
the order listed in the account definition. If a plugin reports
success, the server either accepts the connection if the plugin is
the last one, or proceeds to invoke the next plugin if any remain.
If any plugin reports failure, the server rejects the connection.
</p>
<p>
The following sections cover multifactor authentication in MySQL
in more detail.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="multifactor-authentication.html#multifactor-authentication-elements" title="Elements of Multifactor Authentication Support">
Elements of Multifactor Authentication Support
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="multifactor-authentication.html#multifactor-authentication-policy" title="Configuring the Multifactor Authentication Policy">
Configuring the Multifactor Authentication Policy
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="multifactor-authentication.html#multifactor-authentication-getting-started" title="Getting Started with Multifactor Authentication">
Getting Started with Multifactor Authentication
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="multifactor-authentication-elements">
</a>
Elements of Multifactor Authentication Support
</h4>
</div>
</div>
</div>
<p>
Authentication factors commonly include these types of
information:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Something you know, such as a secret password or passphrase.
</p>
</li>
<li class="listitem">
<p>
Something you have, such as a security key or smart card.
</p>
</li>
<li class="listitem">
<p>
Something you are; that is, a biometric characteristic such
as a fingerprint or facial scan.
</p>
</li>
</ul>
</div>
<p>
The
<span class="quote">
“
<span class="quote">
something you know
</span>
”
</span>
factor type relies on
information that is kept secret on both sides of the
authentication process. Unfortunately, secrets may be subject to
compromise: Someone might see you enter your password or fool
you with a phishing attack, a password stored on the server side
might be exposed by a security breach, and so forth. Security
can be improved by using multiple passwords, but each may still
be subject to compromise. Use of the other factor types enables
improved security with less risk of compromise.
</p>
<p>
Implementation of multifactor authentication in MySQL comprises
these elements:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system variable controls how many authentication factors can
be used and the types of authentication permitted for each
factor. That is, it places constraints on
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
and
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
</code>
</a>
statements with
respect to multifactor authentication.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
and
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
</code>
</a>
have syntax
enabling multiple authentication methods to be specified for
new accounts, and for adding, modifying, or dropping
authentication methods for existing accounts. If an account
uses 2FA or 3FA, the
<code class="literal">
mysql.user
</code>
system
table stores information about the additional authentication
factors in the
<code class="literal">
User_attributes
</code>
column.
</p>
</li>
<li class="listitem">
<p>
To enable authentication to the MySQL server using accounts
that require multiple passwords, client programs have
<a class="link" href="connection-options.html#option_general_password1">
<code class="option">
--password1
</code>
</a>
,
<a class="link" href="connection-options.html#option_general_password2">
<code class="option">
--password2
</code>
</a>
, and
<a class="link" href="connection-options.html#option_general_password3">
<code class="option">
--password3
</code>
</a>
options that
permit up to three passwords to be specified. For
applications that use the C API, the
<code class="literal">
MYSQL_OPT_USER_PASSWORD
</code>
option for the
<a class="ulink" href="/doc/c-api/8.4/en/mysql-options4.html" target="_top">
<code class="literal">
mysql_options4()
</code>
</a>
C API
function enables the same capability.
</p>
</li>
<li class="listitem">
<p>
The server-side
<code class="literal">
authentication_webauthn
</code>
plugin enables authentication using devices. This
server-side, device-based authentication plugin is included
only in MySQL Enterprise Edition distributions. It is not included in MySQL
community distributions. However, the client-side
<code class="literal">
authentication_webauthn_client
</code>
plugin is
included in all distributions, including community
distributions. This enables clients from any distribution to
connect to accounts that use
<code class="literal">
authentication_webauthn
</code>
to authenticate
on a server that has that plugin loaded. See
<a class="xref" href="webauthn-pluggable-authentication.html" title="8.4.1.11 WebAuthn Pluggable Authentication">
Section 8.4.1.11, “WebAuthn Pluggable Authentication”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
authentication_webauthn
</code>
also enables
passwordless authentication, if it is the only
authentication plugin used by an account. See
<a class="xref" href="webauthn-pluggable-authentication.html#webauthn-pluggable-authentication-passwordless" title="WebAuthn Passwordless Authentication">
WebAuthn Passwordless Authentication
</a>
.
</p>
</li>
<li class="listitem">
<p>
Multifactor authentication can use non-WebAuthn MySQL
authentication methods, the WebAuthn authentication method,
or a combination of both.
</p>
</li>
<li class="listitem">
<p>
These privileges enable users to perform certain restricted
multifactor authentication-related operations:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
A user who has the
<a class="link" href="privileges-provided.html#priv_authentication-policy-admin">
<code class="literal">
AUTHENTICATION_POLICY_ADMIN
</code>
</a>
privilege is not subject to the constraints imposed by
the
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system variable. (A warning does occur for statements
that otherwise would not be permitted.)
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="privileges-provided.html#priv_passwordless-user-admin">
<code class="literal">
PASSWORDLESS_USER_ADMIN
</code>
</a>
privilege enables creation of
passwordless-authentication accounts and replication of
operations on them.
</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="multifactor-authentication-policy">
</a>
Configuring the Multifactor Authentication Policy
</h4>
</div>
</div>
</div>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system variable defines the multifactor authentication policy.
Specifically, it defines how many authentication factors
accounts may have (or are required to have) and the
authentication methods that can be used for each factor.
</p>
<p>
The value of
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
is a list
of 1, 2, or 3 comma-separated elements. Each element in the list
corresponds to an authentication factor and can be an
authentication plugin name, an asterisk (
<code class="literal">
*
</code>
),
empty, or missing. (Exception: Element 1 cannot be empty or
missing.) The entire list is enclosed in single quotes. For
example, the following
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
value
includes an asterisk, an authentication plugin name, and an
empty element:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa11708080"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple">authentication_policy <span class="token operator">=</span> '<span class="token operator">*</span><span class="token punctuation">,</span>authentication_webauthn<span class="token punctuation">,</span>'</code></pre>
</div>
<p>
An asterisk (
<code class="literal">
*
</code>
) indicates that an
authentication method is required but any method is permitted.
An empty element indicates that an authentication method is
optional and any method is permitted. A missing element (no
asterisk, empty element, or authentication plugin name)
indicates that an authentication method is not permitted. When a
plugin name is specified, that authentication method is required
for the respective factor when creating or modifying an account.
</p>
<p>
The default
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
value is
<code class="literal">
'*,,'
</code>
(an asterisk and two empty elements),
which requires a first factor, and optionally permits second and
third factors. The default
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
value is
thus backward compatible with existing 1FA accounts, but also
permits creation or modification of accounts to use 2FA or 3FA.
</p>
<p>
A user who has the
<a class="link" href="privileges-provided.html#priv_authentication-policy-admin">
<code class="literal">
AUTHENTICATION_POLICY_ADMIN
</code>
</a>
privilege is not subject to the constraints imposed by the
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
setting.
(A warning occurs for statements that otherwise would not be
permitted.)
</p>
<p>
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
values
can be defined in an option file or specified using a
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
GLOBAL
</code>
</a>
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa28759971"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> authentication_policy<span class="token operator">=</span><span class="token string">'*,*,'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
There are several rules that govern how the
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
value can
be defined. Refer to the
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system
variable description for a compete account of those rules. The
following table provides several
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
example
values and the policy established by each.
</p>
<div class="table">
<a name="idm46045247947552">
</a>
<p class="title">
<b>
Table 8.11 Example authentication_policy Values
</b>
</p>
<div class="table-contents">
<table summary="Example authentication_policy values and their meanings.">
<colgroup>
<col style="width: 50%"/>
<col style="width: 50"/>
</colgroup>
<thead>
<tr>
<th>
authentication_policy Value
</th>
<th>
Effective Policy
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="literal">
'*'
</code>
</td>
<td>
Permit only creating or altering accounts with one factor.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,*'
</code>
</td>
<td>
Permit only creating or altering accounts with two factors.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,*,*'
</code>
</td>
<td>
Permit only creating or altering accounts with three factors.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,'
</code>
</td>
<td>
Permit creating or altering accounts with one or two factors.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,,'
</code>
</td>
<td>
Permit creating or altering accounts with one, two, or three factors.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,*,'
</code>
</td>
<td>
Permit creating or altering accounts with two or three factors.
</td>
</tr>
<tr>
<td>
<code class="literal">
'*,
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
'
</code>
</td>
<td>
Permit creating or altering accounts with two factors, where the first
factor can be any authentication method, and the second
factor must be the named plugin.
</td>
</tr>
<tr>
<td>
<code class="literal">
'
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
,*,'
</code>
</td>
<td>
Permit creating or altering accounts with two or three factors, where
the first factor must be the named plugin.
</td>
</tr>
<tr>
<td>
<code class="literal">
'
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
,'
</code>
</td>
<td>
Permit creating or altering accounts with one or two factors, where the
first factor must be the named plugin.
</td>
</tr>
<tr>
<td>
<code class="literal">
'
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
,
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
,
<em class="replaceable">
<code>
auth_plugin
</code>
</em>
'
</code>
</td>
<td>
Permits creating or altering accounts with three factors, where the
factors must use the named plugins.
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 369px;">
authentication_policy Value
</th>
<th style="width: 369px;">
Effective Policy
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="multifactor-authentication-getting-started">
</a>
Getting Started with Multifactor Authentication
</h4>
</div>
</div>
</div>
<p>
By default, MySQL uses a multifactor authentication policy that
permits any authentication plugin for the first factor, and
optionally permits second and third authentication factors. This
policy is configurable; for details, see
<a class="xref" href="multifactor-authentication.html#multifactor-authentication-policy" title="Configuring the Multifactor Authentication Policy">
Configuring the Multifactor Authentication Policy
</a>
.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
It is not permitted to use any internal credential storage
plugins (
<code class="literal">
caching_sha2_password
</code>
or
<code class="literal">
mysql_native_password
</code>
) for factor 2 or 3.
</p>
</div>
<p>
Suppose that you want an account to authenticate first using the
<code class="literal">
caching_sha2_password
</code>
plugin, then using the
<code class="literal">
authentication_ldap_sasl
</code>
SASL LDAP plugin.
(This assumes that LDAP authentication is already set up as
described in
<a class="xref" href="ldap-pluggable-authentication.html" title="8.4.1.7 LDAP Pluggable Authentication">
Section 8.4.1.7, “LDAP Pluggable Authentication”
</a>
,
and that the user has an entry in the LDAP directory
corresponding to the authentication string shown in the
example.) Create the account using a statement like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa16701669"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span>
<span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> caching_sha2_password
<span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">sha2_password</em>'</span>
<span class="token operator">AND</span> <span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> authentication_ldap_sasl
<span class="token keyword">AS</span> <span class="token string">'uid=u1_ldap,ou=People,dc=example,dc=com'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
To connect, the user must supply two passwords. To enable
authentication to the MySQL server using accounts that require
multiple passwords, client programs have
<a class="link" href="connection-options.html#option_general_password1">
<code class="option">
--password1
</code>
</a>
,
<a class="link" href="connection-options.html#option_general_password2">
<code class="option">
--password2
</code>
</a>
, and
<a class="link" href="connection-options.html#option_general_password3">
<code class="option">
--password3
</code>
</a>
options that permit
up to three passwords to be specified. These options are similar
to the
<a class="link" href="connection-options.html#option_general_password">
<code class="option">
--password
</code>
</a>
option in that
they can take a password value following the option on the
command line (which is insecure) or if given without a password
value cause the user to be prompted for one. For the account
just created, factors 1 and 2 take passwords, so invoke the
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
client with the
<a class="link" href="mysql-command-options.html#option_mysql_password1">
<code class="option">
--password1
</code>
</a>
and
<a class="link" href="mysql-command-options.html#option_mysql_password2">
<code class="option">
--password2
</code>
</a>
options.
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
prompts for each password in turn:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa16941170"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysql</span> <span class="token constant">--user</span><span class="token attr-value"><span class="token punctuation">=</span>alice</span> <span class="token property">--password1</span> <span class="token property">--password2</span>
Enter password<span class="token punctuation">:</span> <span class="token punctuation"></span><em class="replaceable"><span class="token punctuation">(</span>enter factor 1 password<span class="token punctuation">)</span></em><span class="token punctuation"></span>
Enter password<span class="token punctuation">:</span> <span class="token punctuation"></span><em class="replaceable"><span class="token punctuation">(</span>enter factor 2 password<span class="token punctuation">)</span></em><span class="token punctuation"></span></code></pre>
</div>
<p>
Suppose you want to add a third authentication factor. This can
be achieved by dropping and recreating the user with a third
factor or by using
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
<em class="replaceable">
<code>
user
</code>
</em>
ADD
<em class="replaceable">
<code>
factor
</code>
</em>
</code>
</a>
syntax. Both methods
are shown below:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa19938233"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span><span class="token punctuation">;</span>
<span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span>
<span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> caching_sha2_password
<span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">sha2_password</em>'</span>
<span class="token operator">AND</span> <span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> authentication_ldap_sasl
<span class="token keyword">AS</span> <span class="token string">'uid=u1_ldap,ou=People,dc=example,dc=com'</span>
<span class="token operator">AND</span> <span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> authentication_webauthn<span class="token punctuation">;</span></code></pre>
</div>
<p>
<code class="literal">
ADD
<em class="replaceable">
<code>
factor
</code>
</em>
</code>
syntax
includes the factor number and
<code class="literal">
FACTOR
</code>
keyword:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa17515829"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span> <span class="token keyword">ADD</span> <span class="token number">3</span> FACTOR <span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> authentication_webauthn<span class="token punctuation">;</span></code></pre>
</div>
<p>
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
<em class="replaceable">
<code>
user
</code>
</em>
DROP
<em class="replaceable">
<code>
factor
</code>
</em>
</code>
</a>
syntax permits
dropping a factor. The following example drops the third factor
(
<code class="literal">
authentication_webauthn
</code>
) that was added in
the previous example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa17512122"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span> <span class="token keyword">DROP</span> <span class="token number">3</span> FACTOR<span class="token punctuation">;</span></code></pre>
</div>
<p>
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
<em class="replaceable">
<code>
user
</code>
</em>
MODIFY
<em class="replaceable">
<code>
factor
</code>
</em>
</code>
</a>
syntax permits
changing the plugin or authentication string for a particular
factor, provided that the factor exists. The following example
modifies the second factor, changing the authentication method
from
<code class="literal">
authentication_ldap_sasl
</code>
to
<code class="literal">
authetication_webauthn
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa76260624"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">USER</span> <span class="token string">'alice'</span>@<span class="token string">'localhost'</span> <span class="token keyword">MODIFY</span> <span class="token number">2</span> FACTOR <span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> authentication_webauthn<span class="token punctuation">;</span></code></pre>
</div>
<p>
Use
<a class="link" href="show-create-user.html" title="15.7.7.13 SHOW CREATE USER Statement">
<code class="literal">
SHOW CREATE USER
</code>
</a>
to view the
authentication methods defined for an account:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa60053557"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'u1'</span>@<span class="token string">'localhost'</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
CREATE USER for u1@localhost<span class="token punctuation">:</span> CREATE USER `u1`@`localhost`
IDENTIFIED WITH 'caching_sha2_password' AS '<em class="replaceable">sha2_password</em>'
AND IDENTIFIED WITH 'authentication_authn' REQUIRE NONE
PASSWORD EXPIRE DEFAULT ACCOUNT UNLOCK PASSWORD HISTORY
DEFAULT PASSWORD REUSE INTERVAL DEFAULT PASSWORD REQUIRE
CURRENT DEFAULT</span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-schema-object-index.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="sys-schema-object-index">
</a>
30.4.1 sys Schema Object Index
</h3>
</div>
</div>
</div>
<p>
The following tables list
<a class="link" href="sys-schema.html" title="Chapter 30 MySQL sys Schema">
<code class="literal">
sys
</code>
</a>
schema objects and provide a short description of each one.
</p>
<div class="table">
<a name="sys-schema-tables-table">
</a>
<p class="title">
<b>
Table 30.1 sys Schema Tables and Triggers
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Tables and triggers used in the sys schema implementation.">
<colgroup>
<col style="width: 28%"/>
<col style="width: 71%"/>
</colgroup>
<thead>
<tr>
<th>
Table or Trigger Name
</th>
<th>
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="sys-sys-config.html" title="30.4.2.1 The sys_config Table">
<code class="literal">
sys_config
</code>
</a>
</td>
<td>
sys schema configuration options table
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-sys-config-insert-set-user.html" title="30.4.2.2 The sys_config_insert_set_user Trigger">
<code class="literal">
sys_config_insert_set_user
</code>
</a>
</td>
<td>
sys_config insert trigger
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-sys-config-update-set-user.html" title="30.4.2.3 The sys_config_update_set_user Trigger">
<code class="literal">
sys_config_update_set_user
</code>
</a>
</td>
<td>
sys_config update trigger
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a name="sys-schema-views-table">
</a>
<p class="title">
<b>
Table 30.2 sys Schema Views
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Views used in the sys schema implementation.">
<colgroup>
<col style="width: 25%"/>
<col style="width: 62%"/>
<col style="width: 12%"/>
</colgroup>
<thead>
<tr>
<th>
View Name
</th>
<th>
Description
</th>
<th>
Deprecated
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary.html" title="30.4.3.1 The host_summary and x$host_summary Views">
<code class="literal">
host_summary
</code>
,
<code class="literal">
x$host_summary
</code>
</a>
</th>
<td>
Statement activity, file I/O, and connections, grouped by host
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary-by-file-io.html" title="30.4.3.2 The host_summary_by_file_io and x$host_summary_by_file_io Views">
<code class="literal">
host_summary_by_file_io
</code>
,
<code class="literal">
x$host_summary_by_file_io
</code>
</a>
</th>
<td>
File I/O, grouped by host
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary-by-file-io-type.html" title="30.4.3.3 The host_summary_by_file_io_type and x$host_summary_by_file_io_type Views">
<code class="literal">
host_summary_by_file_io_type
</code>
,
<code class="literal">
x$host_summary_by_file_io_type
</code>
</a>
</th>
<td>
File I/O, grouped by host and event type
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary-by-stages.html" title="30.4.3.4 The host_summary_by_stages and x$host_summary_by_stages Views">
<code class="literal">
host_summary_by_stages
</code>
,
<code class="literal">
x$host_summary_by_stages
</code>
</a>
</th>
<td>
Statement stages, grouped by host
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary-by-statement-latency.html" title="30.4.3.5 The host_summary_by_statement_latency and x$host_summary_by_statement_latency Views">
<code class="literal">
host_summary_by_statement_latency
</code>
,
<code class="literal">
x$host_summary_by_statement_latency
</code>
</a>
</th>
<td>
Statement statistics, grouped by host
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-host-summary-by-statement-type.html" title="30.4.3.6 The host_summary_by_statement_type and x$host_summary_by_statement_type Views">
<code class="literal">
host_summary_by_statement_type
</code>
,
<code class="literal">
x$host_summary_by_statement_type
</code>
</a>
</th>
<td>
Statements executed, grouped by host and statement
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-innodb-buffer-stats-by-schema.html" title="30.4.3.7 The innodb_buffer_stats_by_schema and x$innodb_buffer_stats_by_schema Views">
<code class="literal">
innodb_buffer_stats_by_schema
</code>
,
<code class="literal">
x$innodb_buffer_stats_by_schema
</code>
</a>
</th>
<td>
InnoDB buffer information, grouped by schema
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-innodb-buffer-stats-by-table.html" title="30.4.3.8 The innodb_buffer_stats_by_table and x$innodb_buffer_stats_by_table Views">
<code class="literal">
innodb_buffer_stats_by_table
</code>
,
<code class="literal">
x$innodb_buffer_stats_by_table
</code>
</a>
</th>
<td>
InnoDB buffer information, grouped by schema and table
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-innodb-lock-waits.html" title="30.4.3.9 The innodb_lock_waits and x$innodb_lock_waits Views">
<code class="literal">
innodb_lock_waits
</code>
,
<code class="literal">
x$innodb_lock_waits
</code>
</a>
</th>
<td>
InnoDB lock information
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-io-by-thread-by-latency.html" title="30.4.3.10 The io_by_thread_by_latency and x$io_by_thread_by_latency Views">
<code class="literal">
io_by_thread_by_latency
</code>
,
<code class="literal">
x$io_by_thread_by_latency
</code>
</a>
</th>
<td>
I/O consumers, grouped by thread
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-io-global-by-file-by-bytes.html" title="30.4.3.11 The io_global_by_file_by_bytes and x$io_global_by_file_by_bytes Views">
<code class="literal">
io_global_by_file_by_bytes
</code>
,
<code class="literal">
x$io_global_by_file_by_bytes
</code>
</a>
</th>
<td>
Global I/O consumers, grouped by file and bytes
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-io-global-by-file-by-latency.html" title="30.4.3.12 The io_global_by_file_by_latency and x$io_global_by_file_by_latency Views">
<code class="literal">
io_global_by_file_by_latency
</code>
,
<code class="literal">
x$io_global_by_file_by_latency
</code>
</a>
</th>
<td>
Global I/O consumers, grouped by file and latency
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-io-global-by-wait-by-bytes.html" title="30.4.3.13 The io_global_by_wait_by_bytes and x$io_global_by_wait_by_bytes Views">
<code class="literal">
io_global_by_wait_by_bytes
</code>
,
<code class="literal">
x$io_global_by_wait_by_bytes
</code>
</a>
</th>
<td>
Global I/O consumers, grouped by bytes
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-io-global-by-wait-by-latency.html" title="30.4.3.14 The io_global_by_wait_by_latency and x$io_global_by_wait_by_latency Views">
<code class="literal">
io_global_by_wait_by_latency
</code>
,
<code class="literal">
x$io_global_by_wait_by_latency
</code>
</a>
</th>
<td>
Global I/O consumers, grouped by latency
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-latest-file-io.html" title="30.4.3.15 The latest_file_io and x$latest_file_io Views">
<code class="literal">
latest_file_io
</code>
,
<code class="literal">
x$latest_file_io
</code>
</a>
</th>
<td>
Most recent I/O, grouped by file and thread
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-memory-by-host-by-current-bytes.html" title="30.4.3.16 The memory_by_host_by_current_bytes and x$memory_by_host_by_current_bytes Views">
<code class="literal">
memory_by_host_by_current_bytes
</code>
,
<code class="literal">
x$memory_by_host_by_current_bytes
</code>
</a>
</th>
<td>
Memory use, grouped by host
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-memory-by-thread-by-current-bytes.html" title="30.4.3.17 The memory_by_thread_by_current_bytes and x$memory_by_thread_by_current_bytes Views">
<code class="literal">
memory_by_thread_by_current_bytes
</code>
,
<code class="literal">
x$memory_by_thread_by_current_bytes
</code>
</a>
</th>
<td>
Memory use, grouped by thread
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-memory-by-user-by-current-bytes.html" title="30.4.3.18 The memory_by_user_by_current_bytes and x$memory_by_user_by_current_bytes Views">
<code class="literal">
memory_by_user_by_current_bytes
</code>
,
<code class="literal">
x$memory_by_user_by_current_bytes
</code>
</a>
</th>
<td>
Memory use, grouped by user
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-memory-global-by-current-bytes.html" title="30.4.3.19 The memory_global_by_current_bytes and x$memory_global_by_current_bytes Views">
<code class="literal">
memory_global_by_current_bytes
</code>
,
<code class="literal">
x$memory_global_by_current_bytes
</code>
</a>
</th>
<td>
Memory use, grouped by allocation type
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-memory-global-total.html" title="30.4.3.20 The memory_global_total and x$memory_global_total Views">
<code class="literal">
memory_global_total
</code>
,
<code class="literal">
x$memory_global_total
</code>
</a>
</th>
<td>
Total memory use
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-metrics.html" title="30.4.3.21 The metrics View">
<code class="literal">
metrics
</code>
</a>
</th>
<td>
Server metrics
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-processlist.html" title="30.4.3.22 The processlist and x$processlist Views">
<code class="literal">
processlist
</code>
,
<code class="literal">
x$processlist
</code>
</a>
</th>
<td>
Processlist information
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-check-lost-instrumentation.html" title="30.4.3.23 The ps_check_lost_instrumentation View">
<code class="literal">
ps_check_lost_instrumentation
</code>
</a>
</th>
<td>
Variables that have lost instruments
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-auto-increment-columns.html" title="30.4.3.24 The schema_auto_increment_columns View">
<code class="literal">
schema_auto_increment_columns
</code>
</a>
</th>
<td>
AUTO_INCREMENT column information
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-index-statistics.html" title="30.4.3.25 The schema_index_statistics and x$schema_index_statistics Views">
<code class="literal">
schema_index_statistics
</code>
,
<code class="literal">
x$schema_index_statistics
</code>
</a>
</th>
<td>
Index statistics
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-object-overview.html" title="30.4.3.26 The schema_object_overview View">
<code class="literal">
schema_object_overview
</code>
</a>
</th>
<td>
Types of objects within each schema
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-redundant-indexes.html" title="30.4.3.27 The schema_redundant_indexes and x$schema_flattened_keys Views">
<code class="literal">
schema_redundant_indexes
</code>
</a>
</th>
<td>
Duplicate or redundant indexes
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-table-lock-waits.html" title="30.4.3.28 The schema_table_lock_waits and x$schema_table_lock_waits Views">
<code class="literal">
schema_table_lock_waits
</code>
,
<code class="literal">
x$schema_table_lock_waits
</code>
</a>
</th>
<td>
Sessions waiting for metadata locks
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-table-statistics.html" title="30.4.3.29 The schema_table_statistics and x$schema_table_statistics Views">
<code class="literal">
schema_table_statistics
</code>
,
<code class="literal">
x$schema_table_statistics
</code>
</a>
</th>
<td>
Table statistics
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-table-statistics-with-buffer.html" title="30.4.3.30 The schema_table_statistics_with_buffer and x$schema_table_statistics_with_buffer Views">
<code class="literal">
schema_table_statistics_with_buffer
</code>
,
<code class="literal">
x$schema_table_statistics_with_buffer
</code>
</a>
</th>
<td>
Table statistics, including InnoDB buffer pool statistics
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-tables-with-full-table-scans.html" title="30.4.3.31 The schema_tables_with_full_table_scans and x$schema_tables_with_full_table_scans Views">
<code class="literal">
schema_tables_with_full_table_scans
</code>
,
<code class="literal">
x$schema_tables_with_full_table_scans
</code>
</a>
</th>
<td>
Tables being accessed with full scans
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-unused-indexes.html" title="30.4.3.32 The schema_unused_indexes View">
<code class="literal">
schema_unused_indexes
</code>
</a>
</th>
<td>
Indexes not in active use
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-session.html" title="30.4.3.33 The session and x$session Views">
<code class="literal">
session
</code>
,
<code class="literal">
x$session
</code>
</a>
</th>
<td>
Processlist information for user sessions
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-session-ssl-status.html" title="30.4.3.34 The session_ssl_status View">
<code class="literal">
session_ssl_status
</code>
</a>
</th>
<td>
Connection SSL information
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statement-analysis.html" title="30.4.3.35 The statement_analysis and x$statement_analysis Views">
<code class="literal">
statement_analysis
</code>
,
<code class="literal">
x$statement_analysis
</code>
</a>
</th>
<td>
Statement aggregate statistics
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-errors-or-warnings.html" title="30.4.3.36 The statements_with_errors_or_warnings and x$statements_with_errors_or_warnings Views">
<code class="literal">
statements_with_errors_or_warnings
</code>
,
<code class="literal">
x$statements_with_errors_or_warnings
</code>
</a>
</th>
<td>
Statements that have produced errors or warnings
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-full-table-scans.html" title="30.4.3.37 The statements_with_full_table_scans and x$statements_with_full_table_scans Views">
<code class="literal">
statements_with_full_table_scans
</code>
,
<code class="literal">
x$statements_with_full_table_scans
</code>
</a>
</th>
<td>
Statements that have done full table scans
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-runtimes-in-95th-percentile.html" title="30.4.3.38 The statements_with_runtimes_in_95th_percentile and x$statements_with_runtimes_in_95th_percentile Views">
<code class="literal">
statements_with_runtimes_in_95th_percentile
</code>
,
<code class="literal">
x$statements_with_runtimes_in_95th_percentile
</code>
</a>
</th>
<td>
Statements with highest average runtime
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-sorting.html" title="30.4.3.39 The statements_with_sorting and x$statements_with_sorting Views">
<code class="literal">
statements_with_sorting
</code>
,
<code class="literal">
x$statements_with_sorting
</code>
</a>
</th>
<td>
Statements that performed sorts
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-temp-tables.html" title="30.4.3.40 The statements_with_temp_tables and x$statements_with_temp_tables Views">
<code class="literal">
statements_with_temp_tables
</code>
,
<code class="literal">
x$statements_with_temp_tables
</code>
</a>
</th>
<td>
Statements that used temporary tables
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary.html" title="30.4.3.41 The user_summary and x$user_summary Views">
<code class="literal">
user_summary
</code>
,
<code class="literal">
x$user_summary
</code>
</a>
</th>
<td>
User statement and connection activity
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary-by-file-io.html" title="30.4.3.42 The user_summary_by_file_io and x$user_summary_by_file_io Views">
<code class="literal">
user_summary_by_file_io
</code>
,
<code class="literal">
x$user_summary_by_file_io
</code>
</a>
</th>
<td>
File I/O, grouped by user
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary-by-file-io-type.html" title="30.4.3.43 The user_summary_by_file_io_type and x$user_summary_by_file_io_type Views">
<code class="literal">
user_summary_by_file_io_type
</code>
,
<code class="literal">
x$user_summary_by_file_io_type
</code>
</a>
</th>
<td>
File I/O, grouped by user and event
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary-by-stages.html" title="30.4.3.44 The user_summary_by_stages and x$user_summary_by_stages Views">
<code class="literal">
user_summary_by_stages
</code>
,
<code class="literal">
x$user_summary_by_stages
</code>
</a>
</th>
<td>
Stage events, grouped by user
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary-by-statement-latency.html" title="30.4.3.45 The user_summary_by_statement_latency and x$user_summary_by_statement_latency Views">
<code class="literal">
user_summary_by_statement_latency
</code>
,
<code class="literal">
x$user_summary_by_statement_latency
</code>
</a>
</th>
<td>
Statement statistics, grouped by user
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-user-summary-by-statement-type.html" title="30.4.3.46 The user_summary_by_statement_type and x$user_summary_by_statement_type Views">
<code class="literal">
user_summary_by_statement_type
</code>
,
<code class="literal">
x$user_summary_by_statement_type
</code>
</a>
</th>
<td>
Statements executed, grouped by user and statement
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-version.html" title="30.4.3.47 The version View">
<code class="literal">
version
</code>
</a>
</th>
<td>
Current sys schema and MySQL server versions
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-wait-classes-global-by-avg-latency.html" title="30.4.3.48 The wait_classes_global_by_avg_latency and x$wait_classes_global_by_avg_latency Views">
<code class="literal">
wait_classes_global_by_avg_latency
</code>
,
<code class="literal">
x$wait_classes_global_by_avg_latency
</code>
</a>
</th>
<td>
Wait class average latency, grouped by event class
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-wait-classes-global-by-latency.html" title="30.4.3.49 The wait_classes_global_by_latency and x$wait_classes_global_by_latency Views">
<code class="literal">
wait_classes_global_by_latency
</code>
,
<code class="literal">
x$wait_classes_global_by_latency
</code>
</a>
</th>
<td>
Wait class total latency, grouped by event class
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-waits-by-host-by-latency.html" title="30.4.3.50 The waits_by_host_by_latency and x$waits_by_host_by_latency Views">
<code class="literal">
waits_by_host_by_latency
</code>
,
<code class="literal">
x$waits_by_host_by_latency
</code>
</a>
</th>
<td>
Wait events, grouped by host and event
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-waits-by-user-by-latency.html" title="30.4.3.51 The waits_by_user_by_latency and x$waits_by_user_by_latency Views">
<code class="literal">
waits_by_user_by_latency
</code>
,
<code class="literal">
x$waits_by_user_by_latency
</code>
</a>
</th>
<td>
Wait events, grouped by user and event
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-waits-global-by-latency.html" title="30.4.3.52 The waits_global_by_latency and x$waits_global_by_latency Views">
<code class="literal">
waits_global_by_latency
</code>
,
<code class="literal">
x$waits_global_by_latency
</code>
</a>
</th>
<td>
Wait events, grouped by event
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-runtimes-in-95th-percentile.html" title="30.4.3.38 The statements_with_runtimes_in_95th_percentile and x$statements_with_runtimes_in_95th_percentile Views">
<code class="literal">
x$ps_digest_95th_percentile_by_avg_us
</code>
</a>
</th>
<td>
Helper view for 95th-percentile views
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-statements-with-runtimes-in-95th-percentile.html" title="30.4.3.38 The statements_with_runtimes_in_95th_percentile and x$statements_with_runtimes_in_95th_percentile Views">
<code class="literal">
x$ps_digest_avg_latency_distribution
</code>
</a>
</th>
<td>
Helper view for 95th-percentile views
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-table-statistics.html" title="30.4.3.29 The schema_table_statistics and x$schema_table_statistics Views">
<code class="literal">
x$ps_schema_table_statistics_io
</code>
</a>
</th>
<td>
Helper view for table-statistics views
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-schema-redundant-indexes.html" title="30.4.3.27 The schema_redundant_indexes and x$schema_flattened_keys Views">
<code class="literal">
x$schema_flattened_keys
</code>
</a>
</th>
<td>
Helper view for schema_redundant_indexes
</td>
<td>
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 372.641px;">
View Name
</th>
<th style="width: 276.203px;">
Description
</th>
<th style="width: 89.1562px;">
Deprecated
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a name="sys-schema-procedures-table">
</a>
<p class="title">
<b>
Table 30.3 sys Schema Stored Procedures
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Stored procedures used in the sys schema implementation.">
<colgroup>
<col style="width: 28%"/>
<col style="width: 71%"/>
</colgroup>
<thead>
<tr>
<th>
Procedure Name
</th>
<th>
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="sys-create-synonym-db.html" title="30.4.4.1 The create_synonym_db() Procedure">
<code class="literal">
create_synonym_db()
</code>
</a>
</td>
<td>
Create synonym for schema
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-diagnostics.html" title="30.4.4.2 The diagnostics() Procedure">
<code class="literal">
diagnostics()
</code>
</a>
</td>
<td>
Collect system diagnostic information
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-execute-prepared-stmt.html" title="30.4.4.3 The execute_prepared_stmt() Procedure">
<code class="literal">
execute_prepared_stmt()
</code>
</a>
</td>
<td>
Execute prepared statement
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-disable-background-threads.html" title="30.4.4.4 The ps_setup_disable_background_threads() Procedure">
<code class="literal">
ps_setup_disable_background_threads()
</code>
</a>
</td>
<td>
Disable background thread instrumentation
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-disable-consumer.html" title="30.4.4.5 The ps_setup_disable_consumer() Procedure">
<code class="literal">
ps_setup_disable_consumer()
</code>
</a>
</td>
<td>
Disable consumers
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-disable-instrument.html" title="30.4.4.6 The ps_setup_disable_instrument() Procedure">
<code class="literal">
ps_setup_disable_instrument()
</code>
</a>
</td>
<td>
Disable instruments
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-disable-thread.html" title="30.4.4.7 The ps_setup_disable_thread() Procedure">
<code class="literal">
ps_setup_disable_thread()
</code>
</a>
</td>
<td>
Disable instrumentation for thread
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-enable-background-threads.html" title="30.4.4.8 The ps_setup_enable_background_threads() Procedure">
<code class="literal">
ps_setup_enable_background_threads()
</code>
</a>
</td>
<td>
Enable background thread instrumentation
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-enable-consumer.html" title="30.4.4.9 The ps_setup_enable_consumer() Procedure">
<code class="literal">
ps_setup_enable_consumer()
</code>
</a>
</td>
<td>
Enable consumers
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-enable-instrument.html" title="30.4.4.10 The ps_setup_enable_instrument() Procedure">
<code class="literal">
ps_setup_enable_instrument()
</code>
</a>
</td>
<td>
Enable instruments
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-enable-thread.html" title="30.4.4.11 The ps_setup_enable_thread() Procedure">
<code class="literal">
ps_setup_enable_thread()
</code>
</a>
</td>
<td>
Enable instrumentation for thread
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-reload-saved.html" title="30.4.4.12 The ps_setup_reload_saved() Procedure">
<code class="literal">
ps_setup_reload_saved()
</code>
</a>
</td>
<td>
Reload saved Performance Schema configuration
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-reset-to-default.html" title="30.4.4.13 The ps_setup_reset_to_default() Procedure">
<code class="literal">
ps_setup_reset_to_default()
</code>
</a>
</td>
<td>
Reset saved Performance Schema configuration
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-save.html" title="30.4.4.14 The ps_setup_save() Procedure">
<code class="literal">
ps_setup_save()
</code>
</a>
</td>
<td>
Save Performance Schema configuration
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-disabled.html" title="30.4.4.15 The ps_setup_show_disabled() Procedure">
<code class="literal">
ps_setup_show_disabled()
</code>
</a>
</td>
<td>
Display disabled Performance Schema configuration
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-disabled-consumers.html" title="30.4.4.16 The ps_setup_show_disabled_consumers() Procedure">
<code class="literal">
ps_setup_show_disabled_consumers()
</code>
</a>
</td>
<td>
Display disabled Performance Schema consumers
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-disabled-instruments.html" title="30.4.4.17 The ps_setup_show_disabled_instruments() Procedure">
<code class="literal">
ps_setup_show_disabled_instruments()
</code>
</a>
</td>
<td>
Display disabled Performance Schema instruments
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-enabled.html" title="30.4.4.18 The ps_setup_show_enabled() Procedure">
<code class="literal">
ps_setup_show_enabled()
</code>
</a>
</td>
<td>
Display enabled Performance Schema configuration
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-enabled-consumers.html" title="30.4.4.19 The ps_setup_show_enabled_consumers() Procedure">
<code class="literal">
ps_setup_show_enabled_consumers()
</code>
</a>
</td>
<td>
Display enabled Performance Schema consumers
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-setup-show-enabled-instruments.html" title="30.4.4.20 The ps_setup_show_enabled_instruments() Procedure">
<code class="literal">
ps_setup_show_enabled_instruments()
</code>
</a>
</td>
<td>
Display enabled Performance Schema instruments
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-statement-avg-latency-histogram.html" title="30.4.4.21 The ps_statement_avg_latency_histogram() Procedure">
<code class="literal">
ps_statement_avg_latency_histogram()
</code>
</a>
</td>
<td>
Display statement latency histogram
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-trace-statement-digest.html" title="30.4.4.22 The ps_trace_statement_digest() Procedure">
<code class="literal">
ps_trace_statement_digest()
</code>
</a>
</td>
<td>
Trace Performance Schema instrumentation for digest
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-trace-thread.html" title="30.4.4.23 The ps_trace_thread() Procedure">
<code class="literal">
ps_trace_thread()
</code>
</a>
</td>
<td>
Dump Performance Schema data for thread
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-ps-truncate-all-tables.html" title="30.4.4.24 The ps_truncate_all_tables() Procedure">
<code class="literal">
ps_truncate_all_tables()
</code>
</a>
</td>
<td>
Truncate Performance Schema summary tables
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-statement-performance-analyzer.html" title="30.4.4.25 The statement_performance_analyzer() Procedure">
<code class="literal">
statement_performance_analyzer()
</code>
</a>
</td>
<td>
Report of statements running on server
</td>
</tr>
<tr>
<td>
<a class="link" href="sys-table-exists.html" title="30.4.4.26 The table_exists() Procedure">
<code class="literal">
table_exists()
</code>
</a>
</td>
<td>
Whether a table exists
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 307.641px;">
Procedure Name
</th>
<th style="width: 430.359px;">
Description
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a name="sys-schema-functions-table">
</a>
<p class="title">
<b>
Table 30.4 sys Schema Stored Functions
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Stored functions used in the sys schema implementation.">
<colgroup>
<col style="width: 25%"/>
<col style="width: 62%"/>
<col style="width: 12%"/>
</colgroup>
<thead>
<tr>
<th>
Function Name
</th>
<th>
Description
</th>
<th>
Deprecated
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<a class="link" href="sys-extract-schema-from-file-name.html" title="30.4.5.1 The extract_schema_from_file_name() Function">
<code class="literal">
extract_schema_from_file_name()
</code>
</a>
</th>
<td>
Extract schema name part of file name
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-extract-table-from-file-name.html" title="30.4.5.2 The extract_table_from_file_name() Function">
<code class="literal">
extract_table_from_file_name()
</code>
</a>
</th>
<td>
Extract table name part of file name
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-format-bytes.html" title="30.4.5.3 The format_bytes() Function">
<code class="literal">
format_bytes()
</code>
</a>
</th>
<td>
Convert byte count to value with units
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-format-path.html" title="30.4.5.4 The format_path() Function">
<code class="literal">
format_path()
</code>
</a>
</th>
<td>
Replace directories in path name with symbolic system variable names
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-format-statement.html" title="30.4.5.5 The format_statement() Function">
<code class="literal">
format_statement()
</code>
</a>
</th>
<td>
Truncate long statement to fixed length
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-format-time.html" title="30.4.5.6 The format_time() Function">
<code class="literal">
format_time()
</code>
</a>
</th>
<td>
Convert picoseconds time to value with units
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-list-add.html" title="30.4.5.7 The list_add() Function">
<code class="literal">
list_add()
</code>
</a>
</th>
<td>
Add item to list
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-list-drop.html" title="30.4.5.8 The list_drop() Function">
<code class="literal">
list_drop()
</code>
</a>
</th>
<td>
Remove item from list
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-is-account-enabled.html" title="30.4.5.9 The ps_is_account_enabled() Function">
<code class="literal">
ps_is_account_enabled()
</code>
</a>
</th>
<td>
Whether Performance Schema instrumentation for account is enabled
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-is-consumer-enabled.html" title="30.4.5.10 The ps_is_consumer_enabled() Function">
<code class="literal">
ps_is_consumer_enabled()
</code>
</a>
</th>
<td>
Whether Performance Schema consumer is enabled
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-is-instrument-default-enabled.html" title="30.4.5.11 The ps_is_instrument_default_enabled() Function">
<code class="literal">
ps_is_instrument_default_enabled()
</code>
</a>
</th>
<td>
Whether Performance Schema instrument is enabled by default
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-is-instrument-default-timed.html" title="30.4.5.12 The ps_is_instrument_default_timed() Function">
<code class="literal">
ps_is_instrument_default_timed()
</code>
</a>
</th>
<td>
Whether Performance Schema instrument is timed by default
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-is-thread-instrumented.html" title="30.4.5.13 The ps_is_thread_instrumented() Function">
<code class="literal">
ps_is_thread_instrumented()
</code>
</a>
</th>
<td>
Whether Performance Schema instrumentation for connection ID is enabled
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-thread-account.html" title="30.4.5.14 The ps_thread_account() Function">
<code class="literal">
ps_thread_account()
</code>
</a>
</th>
<td>
Account associated with Performance Schema thread ID
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-thread-id.html" title="30.4.5.15 The ps_thread_id() Function">
<code class="literal">
ps_thread_id()
</code>
</a>
</th>
<td>
Performance Schema thread ID associated with connection ID
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-thread-stack.html" title="30.4.5.16 The ps_thread_stack() Function">
<code class="literal">
ps_thread_stack()
</code>
</a>
</th>
<td>
Event information for connection ID
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-ps-thread-trx-info.html" title="30.4.5.17 The ps_thread_trx_info() Function">
<code class="literal">
ps_thread_trx_info()
</code>
</a>
</th>
<td>
Transaction information for thread ID
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-quote-identifier.html" title="30.4.5.18 The quote_identifier() Function">
<code class="literal">
quote_identifier()
</code>
</a>
</th>
<td>
Quote string as identifier
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-sys-get-config.html" title="30.4.5.19 The sys_get_config() Function">
<code class="literal">
sys_get_config()
</code>
</a>
</th>
<td>
sys schema configuration option value
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-version-major.html" title="30.4.5.20 The version_major() Function">
<code class="literal">
version_major()
</code>
</a>
</th>
<td>
MySQL server major version number
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-version-minor.html" title="30.4.5.21 The version_minor() Function">
<code class="literal">
version_minor()
</code>
</a>
</th>
<td>
MySQL server minor version number
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="sys-version-patch.html" title="30.4.5.22 The version_patch() Function">
<code class="literal">
version_patch()
</code>
</a>
</th>
<td>
MySQL server patch release version number
</td>
<td>
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 283.266px;">
Function Name
</th>
<th style="width: 365.578px;">
Description
</th>
<th style="width: 89.1562px;">
Deprecated
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-transaction-tables.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="performance-schema-transaction-tables">
</a>
29.12.7 Performance Schema Transaction Tables
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="performance-schema-events-transactions-current-table.html">
29.12.7.1 The events_transactions_current Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-events-transactions-history-table.html">
29.12.7.2 The events_transactions_history Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-events-transactions-history-long-table.html">
29.12.7.3 The events_transactions_history_long Table
</a>
</span>
</dt>
</dl>
</div>
<p>
The Performance Schema instruments transactions. Within the
event hierarchy, wait events nest within stage events, which
nest within statement events, which nest within transaction
events.
</p>
<p>
These tables store transaction events:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="performance-schema-events-transactions-current-table.html" title="29.12.7.1 The events_transactions_current Table">
<code class="literal">
events_transactions_current
</code>
</a>
:
The current transaction event for each thread.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-events-transactions-history-table.html" title="29.12.7.2 The events_transactions_history Table">
<code class="literal">
events_transactions_history
</code>
</a>
:
The most recent transaction events that have ended per
thread.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-events-transactions-history-long-table.html" title="29.12.7.3 The events_transactions_history_long Table">
<code class="literal">
events_transactions_history_long
</code>
</a>
:
The most recent transaction events that have ended globally
(across all threads).
</p>
</li>
</ul>
</div>
<p>
The following sections describe the transaction event tables.
There are also summary tables that aggregate information about
transaction events; see
<a class="xref" href="performance-schema-transaction-summary-tables.html" title="29.12.20.5 Transaction Summary Tables">
Section 29.12.20.5, “Transaction Summary Tables”
</a>
.
</p>
<p>
For more information about the relationship between the three
transaction event tables, see
<a class="xref" href="performance-schema-event-tables.html" title="29.9 Performance Schema Tables for Current and Historical Events">
Section 29.9, “Performance Schema Tables for Current and Historical Events”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-configuration" title="Configuring Transaction Event Collection">
Configuring Transaction Event Collection
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-transaction-boundaries" title="Transaction Boundaries">
Transaction Boundaries
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-instrumentation" title="Transaction Instrumentation">
Transaction Instrumentation
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-nested-events" title="Transactions and Nested Events">
Transactions and Nested Events
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-stored-programs" title="Transactions and Stored Programs">
Transactions and Stored Programs
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-savepoints" title="Transactions and Savepoints">
Transactions and Savepoints
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="performance-schema-transaction-tables.html#performance-schema-transaction-tables-errors" title="Transactions and Errors">
Transactions and Errors
</a>
</p>
</li>
</ul>
</div>
<h4>
<a name="performance-schema-transaction-tables-configuration">
</a>
Configuring Transaction Event Collection
</h4>
<p>
To control whether to collect transaction events, set the state
of the relevant instruments and consumers:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
table
contains an instrument named
<code class="literal">
transaction
</code>
.
Use this instrument to enable or disable collection of
individual transaction event classes.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="performance-schema-setup-consumers-table.html" title="29.12.2.2 The setup_consumers Table">
<code class="literal">
setup_consumers
</code>
</a>
table
contains consumer values with names corresponding to the
current and historical transaction event table names. Use
these consumers to filter collection of transaction events.
</p>
</li>
</ul>
</div>
<p>
The
<code class="literal">
transaction
</code>
instrument and the
<code class="literal">
events_transactions_current
</code>
and
<code class="literal">
events_transactions_history
</code>
transaction
consumers are enabled by default:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96019525"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">NAME</span><span class="token punctuation">,</span> ENABLED<span class="token punctuation">,</span> TIMED
<span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>setup_instruments
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">=</span> <span class="token string">'transaction'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NAME <span class="token punctuation">|</span> ENABLED <span class="token punctuation">|</span> TIMED <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> transaction <span class="token punctuation">|</span> YES <span class="token punctuation">|</span> YES <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span>
<span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>setup_consumers
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">LIKE</span> <span class="token string">'events_transactions%'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NAME <span class="token punctuation">|</span> ENABLED <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> events_transactions_current <span class="token punctuation">|</span> YES <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> events_transactions_history <span class="token punctuation">|</span> YES <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> events_transactions_history_long <span class="token punctuation">|</span> NO <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
To control transaction event collection at server startup, use
lines like these in your
<code class="filename">
my.cnf
</code>
file:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Enable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa5890499"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">performance-schema-instrument</span><span class="token attr-value"><span class="token punctuation">=</span>'transaction=ON'</span>
<span class="token constant">performance-schema-consumer-events-transactions-current</span><span class="token attr-value"><span class="token punctuation">=</span>ON</span>
<span class="token constant">performance-schema-consumer-events-transactions-history</span><span class="token attr-value"><span class="token punctuation">=</span>ON</span>
<span class="token constant">performance-schema-consumer-events-transactions-history-long</span><span class="token attr-value"><span class="token punctuation">=</span>ON</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Disable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa36179360"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">performance-schema-instrument</span><span class="token attr-value"><span class="token punctuation">=</span>'transaction=OFF'</span>
<span class="token constant">performance-schema-consumer-events-transactions-current</span><span class="token attr-value"><span class="token punctuation">=</span>OFF</span>
<span class="token constant">performance-schema-consumer-events-transactions-history</span><span class="token attr-value"><span class="token punctuation">=</span>OFF</span>
<span class="token constant">performance-schema-consumer-events-transactions-history-long</span><span class="token attr-value"><span class="token punctuation">=</span>OFF</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
To control transaction event collection at runtime, update the
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
and
<a class="link" href="performance-schema-setup-consumers-table.html" title="29.12.2.2 The setup_consumers Table">
<code class="literal">
setup_consumers
</code>
</a>
tables:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Enable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa73659289"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">UPDATE</span> performance_schema<span class="token punctuation">.</span>setup_instruments
<span class="token keyword">SET</span> ENABLED <span class="token operator">=</span> <span class="token string">'YES'</span><span class="token punctuation">,</span> TIMED <span class="token operator">=</span> <span class="token string">'YES'</span>
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">=</span> <span class="token string">'transaction'</span><span class="token punctuation">;</span>
<span class="token keyword">UPDATE</span> performance_schema<span class="token punctuation">.</span>setup_consumers
<span class="token keyword">SET</span> ENABLED <span class="token operator">=</span> <span class="token string">'YES'</span>
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">LIKE</span> <span class="token string">'events_transactions%'</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Disable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa33250019"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">UPDATE</span> performance_schema<span class="token punctuation">.</span>setup_instruments
<span class="token keyword">SET</span> ENABLED <span class="token operator">=</span> <span class="token string">'NO'</span><span class="token punctuation">,</span> TIMED <span class="token operator">=</span> <span class="token string">'NO'</span>
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">=</span> <span class="token string">'transaction'</span><span class="token punctuation">;</span>
<span class="token keyword">UPDATE</span> performance_schema<span class="token punctuation">.</span>setup_consumers
<span class="token keyword">SET</span> ENABLED <span class="token operator">=</span> <span class="token string">'NO'</span>
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">LIKE</span> <span class="token string">'events_transactions%'</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
To collect transaction events only for specific transaction
event tables, enable the
<code class="literal">
transaction
</code>
instrument but only the transaction consumers corresponding to
the desired tables.
</p>
<p>
For additional information about configuring event collection,
see
<a class="xref" href="performance-schema-startup-configuration.html" title="29.3 Performance Schema Startup Configuration">
Section 29.3, “Performance Schema Startup Configuration”
</a>
,
and
<a class="xref" href="performance-schema-runtime-configuration.html" title="29.4 Performance Schema Runtime Configuration">
Section 29.4, “Performance Schema Runtime Configuration”
</a>
.
</p>
<h4>
<a name="performance-schema-transaction-tables-transaction-boundaries">
</a>
Transaction Boundaries
</h4>
<p>
In MySQL Server, transactions start explicitly with these
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa12730215"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">START</span> <span class="token keyword">TRANSACTION</span> <span class="token operator">|</span> <span class="token keyword">BEGIN</span> <span class="token operator">|</span> <span class="token keyword">XA</span> <span class="token keyword">START</span> <span class="token operator">|</span> <span class="token keyword">XA</span> <span class="token keyword">BEGIN</span></code></pre>
</div>
<p>
Transactions also start implicitly. For example, when the
<a class="link" href="server-system-variables.html#sysvar_autocommit">
<code class="literal">
autocommit
</code>
</a>
system variable is
enabled, the start of each statement starts a new transaction.
</p>
<p>
When
<a class="link" href="server-system-variables.html#sysvar_autocommit">
<code class="literal">
autocommit
</code>
</a>
is disabled,
the first statement following a committed transaction marks the
start of a new transaction. Subsequent statements are part of
the transaction until it is committed.
</p>
<p>
Transactions explicitly end with these statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa2941245"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">COMMIT</span> <span class="token operator">|</span> <span class="token keyword">ROLLBACK</span> <span class="token operator">|</span> <span class="token keyword">XA</span> <span class="token keyword">COMMIT</span> <span class="token operator">|</span> <span class="token keyword">XA</span> <span class="token keyword">ROLLBACK</span></code></pre>
</div>
<p>
Transactions also end implicitly, by execution of DDL
statements, locking statements, and server administration
statements.
</p>
<p>
In the following discussion, references to
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
START
TRANSACTION
</code>
</a>
also apply to
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
BEGIN
</code>
</a>
,
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
START
</code>
</a>
, and
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
BEGIN
</code>
</a>
. Similarly, references to
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT
</code>
</a>
and
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
ROLLBACK
</code>
</a>
apply
to
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
COMMIT
</code>
</a>
and
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
ROLLBACK
</code>
</a>
, respectively.
</p>
<p>
The Performance Schema defines transaction boundaries similarly
to that of the server. The start and end of a transaction event
closely match the corresponding state transitions in the server:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For an explicitly started transaction, the transaction event
starts during processing of the
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
START
TRANSACTION
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
For an implicitly started transaction, the transaction event
starts on the first statement that uses a transactional
engine after the previous transaction has ended.
</p>
</li>
<li class="listitem">
<p>
For any transaction, whether explicitly or implicitly ended,
the transaction event ends when the server transitions out
of the active transaction state during the processing of
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT
</code>
</a>
or
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
ROLLBACK
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
There are subtle implications to this approach:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Transaction events in the Performance Schema do not fully
include the statement events associated with the
corresponding
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
START
TRANSACTION
</code>
</a>
,
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT
</code>
</a>
, or
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
ROLLBACK
</code>
</a>
statements. There is a trivial amount of timing overlap
between the transaction event and these statements.
</p>
</li>
<li class="listitem">
<p>
Statements that work with nontransactional engines have no
effect on the transaction state of the connection. For
implicit transactions, the transaction event begins with the
first statement that uses a transactional engine. This means
that statements operating exclusively on nontransactional
tables are ignored, even following
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
START
TRANSACTION
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
To illustrate, consider the following scenario:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa3424206"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">1. SET autocommit = OFF;
2. CREATE TABLE t1 (a INT) ENGINE = InnoDB;
3. START TRANSACTION; -- Transaction 1 START
4. INSERT INTO t1 VALUES (1), (2), (3);
5. CREATE TABLE t2 (a INT) ENGINE = MyISAM; -- Transaction 1 COMMIT
-- (implicit; DDL forces commit)
6. INSERT INTO t2 VALUES (1), (2), (3); -- Update nontransactional table
7. UPDATE t2 SET a = a + 1; -- ... and again
8. INSERT INTO t1 VALUES (4), (5), (6); -- Write to transactional table
-- Transaction 2 START (implicit)
9. COMMIT; -- Transaction 2 COMMIT</code></pre>
</div>
<p>
From the perspective of the server, Transaction 1 ends when
table
<code class="literal">
t2
</code>
is created. Transaction 2 does not
start until a transactional table is accessed, despite the
intervening updates to nontransactional tables.
</p>
<p>
From the perspective of the Performance Schema, Transaction 2
starts when the server transitions into an active transaction
state. Statements 6 and 7 are not included within the boundaries
of Transaction 2, which is consistent with how the server writes
transactions to the binary log.
</p>
<h4>
<a name="performance-schema-transaction-tables-instrumentation">
</a>
Transaction Instrumentation
</h4>
<p>
Three attributes define transactions:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Access mode (read only, read write)
</p>
</li>
<li class="listitem">
<p>
Isolation level
(
<a class="link" href="innodb-transaction-isolation-levels.html#isolevel_serializable">
<code class="literal">
SERIALIZABLE
</code>
</a>
,
<a class="link" href="innodb-transaction-isolation-levels.html#isolevel_repeatable-read">
<code class="literal">
REPEATABLE READ
</code>
</a>
, and so
forth)
</p>
</li>
<li class="listitem">
<p>
Implicit (
<a class="link" href="server-system-variables.html#sysvar_autocommit">
<code class="literal">
autocommit
</code>
</a>
enabled) or explicit
(
<a class="link" href="server-system-variables.html#sysvar_autocommit">
<code class="literal">
autocommit
</code>
</a>
disabled)
</p>
</li>
</ul>
</div>
<p>
To reduce complexity of the transaction instrumentation and to
ensure that the collected transaction data provides complete,
meaningful results, all transactions are instrumented
independently of access mode, isolation level, or autocommit
mode.
</p>
<p>
To selectively examine transaction history, use the attribute
columns in the transaction event tables:
<code class="literal">
ACCESS_MODE
</code>
,
<code class="literal">
ISOLATION_LEVEL
</code>
, and
<code class="literal">
AUTOCOMMIT
</code>
.
</p>
<p>
The cost of transaction instrumentation can be reduced various
ways, such as enabling or disabling transaction instrumentation
according to user, account, host, or thread (client connection).
</p>
<h4>
<a name="performance-schema-transaction-tables-nested-events">
</a>
Transactions and Nested Events
</h4>
<p>
The parent of a transaction event is the event that initiated
the transaction. For an explicitly started transaction, this
includes the
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
START
TRANSACTION
</code>
</a>
and
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT AND
CHAIN
</code>
</a>
statements. For an implicitly started
transaction, it is the first statement that uses a transactional
engine after the previous transaction ends.
</p>
<p>
In general, a transaction is the top-level parent to all events
initiated during the transaction, including statements that
explicitly end the transaction such as
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT
</code>
</a>
and
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
ROLLBACK
</code>
</a>
.
Exceptions are statements that implicitly end a transaction,
such as DDL statements, in which case the current transaction
must be committed before the new statement is executed.
</p>
<h4>
<a name="performance-schema-transaction-tables-stored-programs">
</a>
Transactions and Stored Programs
</h4>
<p>
Transactions and stored program events are related as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Stored Procedures
</p>
<p>
Stored procedures operate independently of transactions. A
stored procedure can be started within a transaction, and a
transaction can be started or ended from within a stored
procedure. If called from within a transaction, a stored
procedure can execute statements that force a commit of the
parent transaction and then start a new transaction.
</p>
<p>
If a stored procedure is started within a transaction, that
transaction is the parent of the stored procedure event.
</p>
<p>
If a transaction is started by a stored procedure, the
stored procedure is the parent of the transaction event.
</p>
</li>
<li class="listitem">
<p>
Stored Functions
</p>
<p>
Stored functions are restricted from causing an explicit or
implicit commit or rollback. Stored function events can
reside within a parent transaction event.
</p>
</li>
<li class="listitem">
<p>
Triggers
</p>
<p>
Triggers activate as part of a statement that accesses the
table with which it is associated, so the parent of a
trigger event is always the statement that activates it.
</p>
<p>
Triggers cannot issue statements that cause an explicit or
implicit commit or rollback of a transaction.
</p>
</li>
<li class="listitem">
<p>
Scheduled Events
</p>
<p>
The execution of the statements in the body of a scheduled
event takes place in a new connection. Nesting of a
scheduled event within a parent transaction is not
applicable.
</p>
</li>
</ul>
</div>
<h4>
<a name="performance-schema-transaction-tables-savepoints">
</a>
Transactions and Savepoints
</h4>
<p>
Savepoint statements are recorded as separate statement events.
Transaction events include separate counters for
<a class="link" href="savepoint.html" title="15.3.4 SAVEPOINT, ROLLBACK TO SAVEPOINT, and RELEASE SAVEPOINT Statements">
<code class="literal">
SAVEPOINT
</code>
</a>
,
<a class="link" href="savepoint.html" title="15.3.4 SAVEPOINT, ROLLBACK TO SAVEPOINT, and RELEASE SAVEPOINT Statements">
<code class="literal">
ROLLBACK TO
SAVEPOINT
</code>
</a>
, and
<a class="link" href="savepoint.html" title="15.3.4 SAVEPOINT, ROLLBACK TO SAVEPOINT, and RELEASE SAVEPOINT Statements">
<code class="literal">
RELEASE
SAVEPOINT
</code>
</a>
statements issued during the transaction.
</p>
<h4>
<a name="performance-schema-transaction-tables-errors">
</a>
Transactions and Errors
</h4>
<p>
Errors and warnings that occur within a transaction are recorded
in statement events, but not in the corresponding transaction
event. This includes transaction-specific errors and warnings,
such as a rollback on a nontransactional table or GTID
consistency errors.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-backup-concepts.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysql-cluster-backup-concepts">
</a>
25.6.8.1 NDB Cluster Backup Concepts
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045092145968">
</a>
<a class="indexterm" name="idm46045092144480">
</a>
<p>
A backup is a snapshot of the database at a given time. The
backup consists of three main parts:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<b>
Metadata.
</b>
The names and definitions of all database tables
</p>
</li>
<li class="listitem">
<p>
<b>
Table records.
</b>
The data actually stored in the database tables at the
time that the backup was made
</p>
</li>
<li class="listitem">
<p>
<b>
Transaction log.
</b>
A sequential record telling how and when data was stored
in the database
</p>
</li>
</ul>
</div>
<p>
Each of these parts is saved on all nodes participating in the
backup. During backup, each node saves these three parts into
three files on disk:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="filename">
BACKUP-
<em class="replaceable">
<code>
backup_id
</code>
</em>
.
<em class="replaceable">
<code>
node_id
</code>
</em>
.ctl
</code>
</p>
<p>
A control file containing control information and metadata.
Each node saves the same table definitions (for all tables
in the cluster) to its own version of this file.
</p>
</li>
<li class="listitem">
<p>
<code class="filename">
BACKUP-
<em class="replaceable">
<code>
backup_id
</code>
</em>
-0.
<em class="replaceable">
<code>
node_id
</code>
</em>
.data
</code>
</p>
<p>
A data file containing the table records, which are saved on
a per-fragment basis. That is, different nodes save
different fragments during the backup. The file saved by
each node starts with a header that states the tables to
which the records belong. Following the list of records
there is a footer containing a checksum for all records.
</p>
</li>
<li class="listitem">
<p>
<code class="filename">
BACKUP-
<em class="replaceable">
<code>
backup_id
</code>
</em>
.
<em class="replaceable">
<code>
node_id
</code>
</em>
.log
</code>
</p>
<p>
A log file containing records of committed transactions.
Only transactions on tables stored in the backup are stored
in the log. Nodes involved in the backup save different
records because different nodes host different database
fragments.
</p>
</li>
</ul>
</div>
<p>
In the listing just shown,
<em class="replaceable">
<code>
backup_id
</code>
</em>
stands for the backup identifier and
<em class="replaceable">
<code>
node_id
</code>
</em>
is the unique identifier for
the node creating the file.
</p>
<p>
The location of the backup files is determined by the
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-backupdatadir">
<code class="literal">
BackupDataDir
</code>
</a>
parameter.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/partitioning-management-range-list.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="partitioning-management-range-list">
</a>
26.3.1 Management of RANGE and LIST Partitions
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045083924240">
</a>
<a class="indexterm" name="idm46045083922752">
</a>
<a class="indexterm" name="idm46045083921264">
</a>
<a class="indexterm" name="idm46045083919776">
</a>
<p>
Adding and dropping of range and list partitions are handled in
a similar fashion, so we discuss the management of both sorts of
partitioning in this section. For information about working with
tables that are partitioned by hash or key, see
<a class="xref" href="partitioning-management-hash-key.html" title="26.3.2 Management of HASH and KEY Partitions">
Section 26.3.2, “Management of HASH and KEY Partitions”
</a>
.
</p>
<p>
Dropping a partition from a table that is partitioned by either
<code class="literal">
RANGE
</code>
or by
<code class="literal">
LIST
</code>
can be
accomplished using the
<a class="link" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
<code class="literal">
ALTER
TABLE
</code>
</a>
statement with the
<code class="literal">
DROP
PARTITION
</code>
option. Suppose that you have created a
table that is partitioned by range and then populated with 10
records using the following
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE
TABLE
</code>
</a>
and
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa27349871"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> tr <span class="token punctuation">(</span>id <span class="token datatype">INT</span><span class="token punctuation">,</span> <span class="token keyword">name</span> <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">)</span><span class="token punctuation">,</span> purchased <span class="token datatype">DATE</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span> <span class="token function">YEAR</span><span class="token punctuation">(</span>purchased<span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1990</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1995</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2000</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2005</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p4 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2010</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token keyword">PARTITION</span> p5 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2015</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.28 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> tr <span class="token keyword">VALUES</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token string">'desk organiser'</span><span class="token punctuation">,</span> <span class="token string">'2003-10-15'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token string">'alarm clock'</span><span class="token punctuation">,</span> <span class="token string">'1997-11-05'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span> <span class="token string">'chair'</span><span class="token punctuation">,</span> <span class="token string">'2009-03-10'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token string">'bookcase'</span><span class="token punctuation">,</span> <span class="token string">'1989-01-10'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span> <span class="token string">'exercise bike'</span><span class="token punctuation">,</span> <span class="token string">'2014-05-09'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token string">'sofa'</span><span class="token punctuation">,</span> <span class="token string">'1987-06-05'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">,</span> <span class="token string">'espresso maker'</span><span class="token punctuation">,</span> <span class="token string">'2011-11-22'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">8</span><span class="token punctuation">,</span> <span class="token string">'aquarium'</span><span class="token punctuation">,</span> <span class="token string">'1992-08-04'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">,</span> <span class="token string">'study desk'</span><span class="token punctuation">,</span> <span class="token string">'2006-09-16'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token prompt"> -></span> <span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span> <span class="token string">'lava lamp'</span><span class="token punctuation">,</span> <span class="token string">'1998-12-25'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 10 rows affected (0.05 sec)</span>
<span class="token output">Records: 10 Duplicates: 0 Warnings: 0</span></code></pre>
</div>
<p>
You can see which items should have been inserted into partition
<code class="literal">
p2
</code>
as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa93551934"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tr
<span class="token prompt"> -></span> <span class="token keyword">WHERE</span> purchased <span class="token operator">BETWEEN</span> <span class="token string">'1995-01-01'</span> <span class="token operator">AND</span> <span class="token string">'1999-12-31'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span> purchased <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> alarm clock <span class="token punctuation">|</span> 1997<span class="token punctuation">-</span>11<span class="token punctuation">-</span>05 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> lava lamp <span class="token punctuation">|</span> 1998<span class="token punctuation">-</span>12<span class="token punctuation">-</span>25 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
You can also get this information using partition selection, as
shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa64688815"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tr <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span>p2<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span> purchased <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> alarm clock <span class="token punctuation">|</span> 1997<span class="token punctuation">-</span>11<span class="token punctuation">-</span>05 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> lava lamp <span class="token punctuation">|</span> 1998<span class="token punctuation">-</span>12<span class="token punctuation">-</span>25 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
See
<a class="xref" href="partitioning-selection.html" title="26.5 Partition Selection">
Section 26.5, “Partition Selection”
</a>
, for more
information.
</p>
<p>
To drop the partition named
<code class="literal">
p2
</code>
, execute the
following command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa61940382"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tr <span class="token keyword">DROP</span> <span class="token keyword">PARTITION</span> p2<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.03 sec)</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDBCLUSTER
</code>
</a>
storage engine
does not support
<code class="literal">
ALTER TABLE ... DROP
PARTITION
</code>
. It does, however, support the other
partitioning-related extensions to
<a class="link" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
<code class="literal">
ALTER
TABLE
</code>
</a>
that are described in this chapter.
</p>
</div>
<p>
It is very important to remember that,
<span class="emphasis">
<em>
when you drop a
partition, you also delete all the data that was stored in that
partition
</em>
</span>
. You can see that this is the case by
re-running the previous
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
query:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa94436620"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tr <span class="token keyword">WHERE</span> purchased
<span class="token prompt"> -></span> <span class="token operator">BETWEEN</span> <span class="token string">'1995-01-01'</span> <span class="token operator">AND</span> <span class="token string">'1999-12-31'</span><span class="token punctuation">;</span>
<span class="token output">Empty set (0.00 sec)</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<code class="literal">
DROP PARTITION
</code>
is supported by native
partitioning in-place APIs and may be used with
<code class="literal">
ALGORITHM={COPY|INPLACE}
</code>
.
<code class="literal">
DROP
PARTITION
</code>
with
<code class="literal">
ALGORITHM=INPLACE
</code>
deletes data stored in the partition and drops the partition.
However,
<code class="literal">
DROP PARTITION
</code>
with
<code class="literal">
ALGORITHM=COPY
</code>
or
<a class="link" href="server-system-variables.html#sysvar_old_alter_table">
<code class="literal">
old_alter_table=ON
</code>
</a>
rebuilds
the partitioned table and attempts to move data from the
dropped partition to another partition with a compatible
<code class="literal">
PARTITION ... VALUES
</code>
definition. Data that
cannot be moved to another partition is deleted.
</p>
</div>
<p>
Because of this, you must have the
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
privilege for a table before
you can execute
<code class="literal">
ALTER TABLE ... DROP
PARTITION
</code>
on that table.
</p>
<p>
If you wish to drop all data from all partitions while
preserving the table definition and its partitioning scheme, use
the
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
statement.
(See
<a class="xref" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
Section 15.1.37, “TRUNCATE TABLE Statement”
</a>
.)
</p>
<p>
If you intend to change the partitioning of a table
<span class="emphasis">
<em>
without
</em>
</span>
losing data, use
<code class="literal">
ALTER
TABLE ... REORGANIZE PARTITION
</code>
instead. See below or
in
<a class="xref" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
Section 15.1.9, “ALTER TABLE Statement”
</a>
, for information about
<code class="literal">
REORGANIZE PARTITION
</code>
.
</p>
<p>
If you now execute a
<a class="link" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
<code class="literal">
SHOW CREATE
TABLE
</code>
</a>
statement, you can see how the partitioning
makeup of the table has been changed:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa38416029"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> tr\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Table<span class="token punctuation">:</span> tr
Create Table<span class="token punctuation">:</span> CREATE TABLE `tr` (
`id` int(11) DEFAULT NULL,
`name` varchar(50) DEFAULT NULL,
`purchased` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
/<span class="token punctuation">*</span>!50100 PARTITION BY RANGE ( YEAR(purchased))
(PARTITION p0 VALUES LESS THAN (1990) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1995) ENGINE = InnoDB,
PARTITION p3 VALUES LESS THAN (2005) ENGINE = InnoDB,
PARTITION p4 VALUES LESS THAN (2010) ENGINE = InnoDB,
PARTITION p5 VALUES LESS THAN (2015) ENGINE = InnoDB) <span class="token punctuation">*</span>/
</span><span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
When you insert new rows into the changed table with
<code class="literal">
purchased
</code>
column values between
<code class="literal">
'1995-01-01'
</code>
and
<code class="literal">
'2004-12-31'
</code>
inclusive, those rows are stored
in partition
<code class="literal">
p3
</code>
. You can verify this as
follows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa59775079"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> tr <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">11</span><span class="token punctuation">,</span> <span class="token string">'pencil holder'</span><span class="token punctuation">,</span> <span class="token string">'1995-07-12'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tr <span class="token keyword">WHERE</span> purchased
<span class="token prompt"> -></span> <span class="token operator">BETWEEN</span> <span class="token string">'1995-01-01'</span> <span class="token operator">AND</span> <span class="token string">'2004-12-31'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span> purchased <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> desk organiser <span class="token punctuation">|</span> 2003<span class="token punctuation">-</span>10<span class="token punctuation">-</span>15 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 11 <span class="token punctuation">|</span> pencil holder <span class="token punctuation">|</span> 1995<span class="token punctuation">-</span>07<span class="token punctuation">-</span>12 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tr <span class="token keyword">DROP</span> <span class="token keyword">PARTITION</span> p3<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.03 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tr <span class="token keyword">WHERE</span> purchased
<span class="token prompt"> -></span> <span class="token operator">BETWEEN</span> <span class="token string">'1995-01-01'</span> <span class="token operator">AND</span> <span class="token string">'2004-12-31'</span><span class="token punctuation">;</span>
<span class="token output">Empty set (0.00 sec)</span></code></pre>
</div>
<p>
The number of rows dropped from the table as a result of
<code class="literal">
ALTER TABLE ... DROP PARTITION
</code>
is not
reported by the server as it would be by the equivalent
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
query.
</p>
<p>
Dropping
<code class="literal">
LIST
</code>
partitions uses exactly the
same
<code class="literal">
ALTER TABLE ... DROP PARTITION
</code>
syntax as
used for dropping
<code class="literal">
RANGE
</code>
partitions. However,
there is one important difference in the effect this has on your
use of the table afterward: You can no longer insert into the
table any rows having any of the values that were included in
the value list defining the deleted partition. (See
<a class="xref" href="partitioning-list.html" title="26.2.2 LIST Partitioning">
Section 26.2.2, “LIST Partitioning”
</a>
, for an example.)
</p>
<p>
To add a new range or list partition to a previously partitioned
table, use the
<code class="literal">
ALTER TABLE ... ADD PARTITION
</code>
statement. For tables which are partitioned by
<code class="literal">
RANGE
</code>
, this can be used to add a new range to
the end of the list of existing partitions. Suppose that you
have a partitioned table containing membership data for your
organization, which is defined as follows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa17073534"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> members <span class="token punctuation">(</span>
id <span class="token datatype">INT</span><span class="token punctuation">,</span>
fname <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">25</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
lname <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">25</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
dob <span class="token datatype">DATE</span>
<span class="token punctuation">)</span>
<span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span> <span class="token function">YEAR</span><span class="token punctuation">(</span>dob<span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1980</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1990</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2000</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Suppose further that the minimum age for members is 16. As the
calendar approaches the end of 2015, you realize that you must
soon be prepared to admit members who were born in 2000 (and
later). You can modify the
<code class="literal">
members
</code>
table to
accommodate new members born in the years 2000 to 2010 as shown
here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa98858957"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span><span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2010</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
With tables that are partitioned by range, you can use
<code class="literal">
ADD PARTITION
</code>
to add new partitions to the
high end of the partitions list only. Trying to add a new
partition in this manner between or before existing partitions
results in an error as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa69916575"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members
<span class="token operator">></span> <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span>
<span class="token operator">></span> <span class="token keyword">PARTITION</span> n <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1970</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1463 (HY000)<span class="token punctuation">:</span> VALUES LESS THAN value must be strictly »
increasing for each partition</span></code></pre>
</div>
<p>
You can work around this problem by reorganizing the first
partition into two new ones that split the range between them,
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa45467189"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members
<span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> p0 <span class="token keyword">INTO</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> n0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1970</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> n1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1980</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Using
<a class="link" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
<code class="literal">
SHOW CREATE TABLE
</code>
</a>
you can
see that the
<code class="literal">
ALTER TABLE
</code>
statement has had
the desired effect:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa28617008"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> members\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Table<span class="token punctuation">:</span> members
Create Table<span class="token punctuation">:</span> CREATE TABLE `members` (
`id` int(11) DEFAULT NULL,
`fname` varchar(25) DEFAULT NULL,
`lname` varchar(25) DEFAULT NULL,
`dob` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
/<span class="token punctuation">*</span>!50100 PARTITION BY RANGE ( YEAR(dob))
(PARTITION n0 VALUES LESS THAN (1970) ENGINE = InnoDB,
PARTITION n1 VALUES LESS THAN (1980) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1990) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2000) ENGINE = InnoDB,
PARTITION p3 VALUES LESS THAN (2010) ENGINE = InnoDB) <span class="token punctuation">*</span>/
</span><span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
See also
<a class="xref" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
Section 15.1.9.1, “ALTER TABLE Partition Operations”
</a>
.
</p>
<p>
You can also use
<code class="literal">
ALTER TABLE ... ADD
PARTITION
</code>
to add new partitions to a table that is
partitioned by
<code class="literal">
LIST
</code>
. Suppose a table
<code class="literal">
tt
</code>
is defined using the following
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa45275084"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> tt <span class="token punctuation">(</span>
id <span class="token datatype">INT</span><span class="token punctuation">,</span>
<span class="token keyword">data</span> <span class="token datatype">INT</span>
<span class="token punctuation">)</span>
<span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">LIST</span><span class="token punctuation">(</span><span class="token keyword">data</span><span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">15</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">,</span> <span class="token number">18</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
You can add a new partition in which to store rows having the
<code class="literal">
data
</code>
column values
<code class="literal">
7
</code>
,
<code class="literal">
14
</code>
, and
<code class="literal">
21
</code>
as shown:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa74784917"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tt <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span><span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">,</span> <span class="token number">14</span><span class="token punctuation">,</span> <span class="token number">21</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Keep in mind that you
<span class="emphasis">
<em>
cannot
</em>
</span>
add a new
<code class="literal">
LIST
</code>
partition encompassing any values that
are already included in the value list of an existing partition.
If you attempt to do so, an error results:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa63731974"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tt <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span>
<span class="token operator">></span> <span class="token punctuation">(</span><span class="token keyword">PARTITION</span> np <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1465 (HY000)<span class="token punctuation">:</span> Multiple definition of same constant »
in list partitioning</span></code></pre>
</div>
<p>
Because any rows with the
<code class="literal">
data
</code>
column value
<code class="literal">
12
</code>
have already been assigned to partition
<code class="literal">
p1
</code>
, you cannot create a new partition on
table
<code class="literal">
tt
</code>
that includes
<code class="literal">
12
</code>
in its value list. To accomplish this, you could drop
<code class="literal">
p1
</code>
, and add
<code class="literal">
np
</code>
and then a
new
<code class="literal">
p1
</code>
with a modified definition. However,
as discussed earlier, this would result in the loss of all data
stored in
<code class="literal">
p1
</code>
—and it is often the case
that this is not what you really want to do. Another solution
might appear to be to make a copy of the table with the new
partitioning and to copy the data into it using
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE ...
SELECT ...
</code>
</a>
, then drop the old table and rename the new
one, but this could be very time-consuming when dealing with a
large amounts of data. This also might not be feasible in
situations where high availability is a requirement.
</p>
<p>
You can add multiple partitions in a single
<code class="literal">
ALTER TABLE
... ADD PARTITION
</code>
statement as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa41058868"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> employees <span class="token punctuation">(</span>
id <span class="token datatype">INT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
fname <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
lname <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
hired <span class="token datatype">DATE</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span>
<span class="token punctuation">)</span>
<span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span> <span class="token function">YEAR</span><span class="token punctuation">(</span>hired<span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1991</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1996</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2001</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p4 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2005</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> employees <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p5 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2010</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> p6 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token keyword">MAXVALUE</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Fortunately, MySQL's partitioning implementation provides ways
to redefine partitions without losing data. Let us look first at
a couple of simple examples involving
<code class="literal">
RANGE
</code>
partitioning. Recall the
<code class="literal">
members
</code>
table which
is now defined as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa46338770"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> members\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Table<span class="token punctuation">:</span> members
Create Table<span class="token punctuation">:</span> CREATE TABLE `members` (
`id` int(11) DEFAULT NULL,
`fname` varchar(25) DEFAULT NULL,
`lname` varchar(25) DEFAULT NULL,
`dob` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
/<span class="token punctuation">*</span>!50100 PARTITION BY RANGE ( YEAR(dob))
(PARTITION n0 VALUES LESS THAN (1970) ENGINE = InnoDB,
PARTITION n1 VALUES LESS THAN (1980) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1990) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2000) ENGINE = InnoDB,
PARTITION p3 VALUES LESS THAN (2010) ENGINE = InnoDB) <span class="token punctuation">*</span>/
</span><span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
Suppose that you would like to move all rows representing
members born before 1960 into a separate partition. As we have
already seen, this cannot be done using
<a class="link" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
<code class="literal">
ALTER
TABLE ... ADD PARTITION
</code>
</a>
. However, you can use another
partition-related extension to
<a class="link" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
<code class="literal">
ALTER
TABLE
</code>
</a>
to accomplish this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa71290203"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members <span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> n0 <span class="token keyword">INTO</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> s0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1960</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> s1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1970</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
In effect, this command splits partition
<code class="literal">
p0
</code>
into two new partitions
<code class="literal">
s0
</code>
and
<code class="literal">
s1
</code>
. It also moves the data that was stored in
<code class="literal">
p0
</code>
into the new partitions according to the
rules embodied in the two
<code class="literal">
PARTITION ... VALUES
...
</code>
clauses, so that
<code class="literal">
s0
</code>
contains
only those records for which
<a class="link" href="date-and-time-functions.html#function_year">
<code class="literal">
YEAR(dob)
</code>
</a>
is less than 1960 and
<code class="literal">
s1
</code>
contains those rows in which
<a class="link" href="date-and-time-functions.html#function_year">
<code class="literal">
YEAR(dob)
</code>
</a>
is greater than or
equal to 1960 but less than 1970.
</p>
<p>
A
<code class="literal">
REORGANIZE PARTITION
</code>
clause may also be
used for merging adjacent partitions. You can reverse the effect
of the previous statement on the
<code class="literal">
members
</code>
table as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa26495988"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members <span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> s0<span class="token punctuation">,</span>s1 <span class="token keyword">INTO</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1970</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
No data is lost in splitting or merging partitions using
<code class="literal">
REORGANIZE PARTITION
</code>
. In executing the above
statement, MySQL moves all of the records that were stored in
partitions
<code class="literal">
s0
</code>
and
<code class="literal">
s1
</code>
into
partition
<code class="literal">
p0
</code>
.
</p>
<p>
The general syntax for
<code class="literal">
REORGANIZE PARTITION
</code>
is shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa98955978"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> <em class="replaceable">tbl_name</em>
<span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> <em class="replaceable">partition_list</em>
<span class="token keyword">INTO</span> <span class="token punctuation">(</span><em class="replaceable">partition_definitions</em><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Here,
<em class="replaceable">
<code>
tbl_name
</code>
</em>
is the name of the
partitioned table, and
<em class="replaceable">
<code>
partition_list
</code>
</em>
is a comma-separated list of names of one or more existing
partitions to be changed.
<em class="replaceable">
<code>
partition_definitions
</code>
</em>
is a
comma-separated list of new partition definitions, which follow
the same rules as for the
<em class="replaceable">
<code>
partition_definitions
</code>
</em>
list used in
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
. You are not limited
to merging several partitions into one, or to splitting one
partition into many, when using
<code class="literal">
REORGANIZE
PARTITION
</code>
. For example, you can reorganize all four
partitions of the
<code class="literal">
members
</code>
table into two,
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa70567490"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members <span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> p0<span class="token punctuation">,</span>p1<span class="token punctuation">,</span>p2<span class="token punctuation">,</span>p3 <span class="token keyword">INTO</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> m0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">1980</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> m1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">2000</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
You can also use
<code class="literal">
REORGANIZE PARTITION
</code>
with
tables that are partitioned by
<code class="literal">
LIST
</code>
. Let us
return to the problem of adding a new partition to the
list-partitioned
<code class="literal">
tt
</code>
table and failing because
the new partition had a value that was already present in the
value-list of one of the existing partitions. We can handle this
by adding a partition that contains only nonconflicting values,
and then reorganizing the new partition and the existing one so
that the value which was stored in the existing one is now moved
to the new one:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa62553044"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tt <span class="token keyword">ADD</span> <span class="token keyword">PARTITION</span> <span class="token punctuation">(</span><span class="token keyword">PARTITION</span> np <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tt <span class="token keyword">REORGANIZE</span> <span class="token keyword">PARTITION</span> p1<span class="token punctuation">,</span>np <span class="token keyword">INTO</span> <span class="token punctuation">(</span>
<span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">IN</span> <span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token number">18</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">PARTITION</span> np <span class="token keyword">VALUES</span> <span class="token keyword">in</span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Here are some key points to keep in mind when using
<code class="literal">
ALTER TABLE ... REORGANIZE PARTITION
</code>
to
repartition tables that are partitioned by
<code class="literal">
RANGE
</code>
or
<code class="literal">
LIST
</code>
:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The
<code class="literal">
PARTITION
</code>
options used to determine
the new partitioning scheme are subject to the same rules as
those used with a
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE
TABLE
</code>
</a>
statement.
</p>
<p>
A new
<code class="literal">
RANGE
</code>
partitioning scheme cannot
have any overlapping ranges; a new
<code class="literal">
LIST
</code>
partitioning scheme cannot have any overlapping sets of
values.
</p>
</li>
<li class="listitem">
<p>
The combination of partitions in the
<em class="replaceable">
<code>
partition_definitions
</code>
</em>
list should
account for the same range or set of values overall as the
combined partitions named in the
<em class="replaceable">
<code>
partition_list
</code>
</em>
.
</p>
<p>
For example, partitions
<code class="literal">
p1
</code>
and
<code class="literal">
p2
</code>
together cover the years 1980 through
1999 in the
<code class="literal">
members
</code>
table used as an
example in this section. Any reorganization of these two
partitions should cover the same range of years overall.
</p>
</li>
<li class="listitem">
<p>
For tables partitioned by
<code class="literal">
RANGE
</code>
, you can
reorganize only adjacent partitions; you cannot skip range
partitions.
</p>
<p>
For instance, you could not reorganize the example
<code class="literal">
members
</code>
table using a statement beginning
with
<code class="literal">
ALTER TABLE members REORGANIZE PARTITION p0,p2
INTO ...
</code>
because
<code class="literal">
p0
</code>
covers the
years prior to 1970 and
<code class="literal">
p2
</code>
the years from
1990 through 1999 inclusive, so these are not adjacent
partitions. (You cannot skip partition
<code class="literal">
p1
</code>
in this case.)
</p>
</li>
<li class="listitem">
<p>
You cannot use
<code class="literal">
REORGANIZE PARTITION
</code>
to
change the type of partitioning used by the table (for
example, you cannot change
<code class="literal">
RANGE
</code>
partitions to
<code class="literal">
HASH
</code>
partitions or the
reverse). You also cannot use this statement to change the
partitioning expression or column. To accomplish either of
these tasks without dropping and re-creating the table, you
can use
<a class="link" href="alter-table-partition-operations.html" title="15.1.9.1 ALTER TABLE Partition Operations">
<code class="literal">
ALTER
TABLE ... PARTITION BY ...
</code>
</a>
, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa17975765"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> members
<span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">HASH</span><span class="token punctuation">(</span> <span class="token function">YEAR</span><span class="token punctuation">(</span>dob<span class="token punctuation">)</span> <span class="token punctuation">)</span>
<span class="token keyword">PARTITIONS</span> <span class="token number">8</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/error-log-format.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="error-log-format">
</a>
7.4.2.9 Error Log Output Format
</h4>
</div>
</div>
</div>
<p>
Each error log sink (writer) component has a characteristic
output format it uses to write messages to its destination, but
other factors may influence the content of the messages:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The information available to the log sink. If a log filter
component executed prior to execution of the sink component
removes a log event field, that field is not available for
writing. For information about log filtering, see
<a class="xref" href="error-log-filtering.html" title="7.4.2.4 Types of Error Log Filtering">
Section 7.4.2.4, “Types of Error Log Filtering”
</a>
.
</p>
</li>
<li class="listitem">
<p>
The information relevant to the log sink. Not every sink
writes all fields available in error events.
</p>
</li>
<li class="listitem">
<p>
System variables may affect log sinks. See
<a class="xref" href="error-log-format.html#error-log-format-system-variables" title="System Variables That Affect Error Log Format">
System Variables That Affect Error Log Format
</a>
.
</p>
</li>
</ul>
</div>
<p>
For names and descriptions of the fields in error events, see
<a class="xref" href="error-log-event-fields.html" title="7.4.2.3 Error Event Fields">
Section 7.4.2.3, “Error Event Fields”
</a>
. For all log sinks, the
thread ID included in error log messages is that of the thread
within
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
responsible for writing the
message. This ID indicates which part of the server produced the
message, and is consistent with general query log and slow query
log messages, which include the connection thread ID.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="error-log-format.html#error-log-format-output-format-for-log-sink-internal" title="log_sink_internal Output Format">
log_sink_internal Output Format
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="error-log-format.html#error-log-format-output-format-for-log-sink-json" title="log_sink_json Output Format">
log_sink_json Output Format
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="error-log-format.html#error-log-format-output-format-for-log-sink-syseventlog" title="log_sink_syseventlog Output Format">
log_sink_syseventlog Output Format
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="error-log-format.html#error-log-format-output-format-for-early-logging" title="Early-Startup Logging Output Format">
Early-Startup Logging Output Format
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="error-log-format.html#error-log-format-system-variables" title="System Variables That Affect Error Log Format">
System Variables That Affect Error Log Format
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="error-log-format-output-format-for-log-sink-internal">
</a>
log_sink_internal Output Format
</h5>
</div>
</div>
</div>
<p>
The internal log sink produces traditional error log output.
For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa41919266"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">2020-08-06T14:25:02.835618Z 0 [Note] [MY-012487] [InnoDB] DDL log recovery : begin
2020-08-06T14:25:02.936146Z 0 [Warning] [MY-010068] [Server] CA certificate /var/mysql/sslinfo/cacert.pem is self signed.
2020-08-06T14:25:02.963127Z 0 [Note] [MY-010253] [Server] IPv6 is available.
2020-08-06T14:25:03.109022Z 5 [Note] [MY-010051] [Server] Event Scheduler: scheduler thread started with id 5</code></pre>
</div>
<p>
Traditional-format messages have these fields:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa28340468"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">time thread [label] [err_code] [subsystem] msg</code></pre>
</div>
<p>
The
<code class="literal">
[
</code>
and
<code class="literal">
]
</code>
square
bracket characters are literal characters in the message
format. They do not indicate that fields are optional.
</p>
<p>
The
<code class="literal">
label
</code>
value corresponds to the string
form of the
<code class="literal">
prio
</code>
error event priority
field.
</p>
<p>
The
<code class="literal">
[err_code]
</code>
and
<code class="literal">
[subsystem]
</code>
fields were added in MySQL 8.0,
and thus are missing from logs generated by older servers. Log
parsers can treat these fields as parts of the message text
that is present only for logs written by servers recent enough
to include them. Parsers must treat the
<code class="literal">
err_code
</code>
part of
<code class="literal">
[err_code]
</code>
indicators as a string value,
not a number, because values such as
<code class="literal">
MY-012487
</code>
and
<code class="literal">
MY-010051
</code>
contain nonnumeric characters.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="error-log-format-output-format-for-log-sink-json">
</a>
log_sink_json Output Format
</h5>
</div>
</div>
</div>
<p>
The JSON-format log sink produces messages as JSON objects
that contain key-value pairs. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-json"><div class="docs-select-all right" id="sa34445364"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-json"><span class="token punctuation">{</span>
<span class="token property">"prio"</span><span class="token operator">:</span> <span class="token number">3</span><span class="token punctuation">,</span>
<span class="token property">"err_code"</span><span class="token operator">:</span> <span class="token number">10051</span><span class="token punctuation">,</span>
<span class="token property">"source_line"</span><span class="token operator">:</span> <span class="token number">561</span><span class="token punctuation">,</span>
<span class="token property">"source_file"</span><span class="token operator">:</span> <span class="token string">"event_scheduler.cc"</span><span class="token punctuation">,</span>
<span class="token property">"function"</span><span class="token operator">:</span> <span class="token string">"run"</span><span class="token punctuation">,</span>
<span class="token property">"msg"</span><span class="token operator">:</span> <span class="token string">"Event Scheduler: scheduler thread started with id 5"</span><span class="token punctuation">,</span>
<span class="token property">"time"</span><span class="token operator">:</span> <span class="token string">"2020-08-06T14:25:03.109022Z"</span><span class="token punctuation">,</span>
<span class="token property">"ts"</span><span class="token operator">:</span> <span class="token number">1596724012005</span><span class="token punctuation">,</span>
<span class="token property">"thread"</span><span class="token operator">:</span> <span class="token number">5</span><span class="token punctuation">,</span>
<span class="token property">"err_symbol"</span><span class="token operator">:</span> <span class="token string">"ER_SCHEDULER_STARTED"</span><span class="token punctuation">,</span>
<span class="token property">"SQL_state"</span><span class="token operator">:</span> <span class="token string">"HY000"</span><span class="token punctuation">,</span>
<span class="token property">"subsystem"</span><span class="token operator">:</span> <span class="token string">"Server"</span><span class="token punctuation">,</span>
<span class="token property">"buffered"</span><span class="token operator">:</span> <span class="token number">1596723903109022</span><span class="token punctuation">,</span>
<span class="token property">"label"</span><span class="token operator">:</span> <span class="token string">"Note"</span>
<span class="token punctuation">}</span></code></pre>
</div>
<p>
The message shown is reformatted for readability. Events
written to the error log appear one message per line.
</p>
<a class="indexterm" name="idm46045258468832">
</a>
<p>
The
<code class="literal">
ts
</code>
(timestamp) key is unique to the
JSON-format log sink. The value is an integer indicating
milliseconds since the epoch (
<code class="literal">
'1970-01-01
00:00:00'
</code>
UTC).
</p>
<p>
The
<code class="literal">
ts
</code>
and
<code class="literal">
buffered
</code>
values are Unix timestamp values and can be converted using
<a class="link" href="date-and-time-functions.html#function_from-unixtime">
<code class="literal">
FROM_UNIXTIME()
</code>
</a>
and an
appropriate divisor:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa6862414"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> time_zone <span class="token operator">=</span> <span class="token string">'+00:00'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">FROM_UNIXTIME</span><span class="token punctuation">(</span><span class="token number">1596724012005</span><span class="token operator">/</span><span class="token number">1000.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> FROM_UNIXTIME(1596724012005/1000.0) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2020<span class="token punctuation">-</span>08<span class="token punctuation">-</span>06 14:26:52.0050 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">FROM_UNIXTIME</span><span class="token punctuation">(</span><span class="token number">1596723903109022</span><span class="token operator">/</span><span class="token number">1000000.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> FROM_UNIXTIME(1596723903109022/1000000.0) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2020<span class="token punctuation">-</span>08<span class="token punctuation">-</span>06 14:25:03.1090 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="error-log-format-output-format-for-log-sink-syseventlog">
</a>
log_sink_syseventlog Output Format
</h5>
</div>
</div>
</div>
<p>
The system log sink produces output that conforms to the
system log format used on the local platform.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="error-log-format-output-format-for-early-logging">
</a>
Early-Startup Logging Output Format
</h5>
</div>
</div>
</div>
<p>
The server generates some error log messages before startup
options have been processed, and thus before it knows error
log settings such as the
<a class="link" href="server-system-variables.html#sysvar_log_error_verbosity">
<code class="literal">
log_error_verbosity
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_log_timestamps">
<code class="literal">
log_timestamps
</code>
</a>
system
variable values, and before it knows which log components are
to be used. The server handles error log messages that are
generated early in the startup process as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The server buffers log events (rather than formatted log
messages), which enables it to apply configuration
settings to those events retroactively, after the settings
are known, with the result that flushed messages use the
configured settings, not the defaults. Also, messages are
flushed to all configured sinks, not just the default
sink.
</p>
<p>
If a fatal error occurs before log configuration is known
and the server must exit, the server formats buffered
messages using the logging defaults so they are not lost.
If no fatal error occurs but startup is excessively slow
prior to processing startup options, the server
periodically formats and flushes buffered messages using
the logging defaults so as not to appear unresponsive.
Although this behavior uses the defaults, it is preferable
to losing messages when exceptional conditions occur.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="error-log-format-system-variables">
</a>
System Variables That Affect Error Log Format
</h5>
</div>
</div>
</div>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_log_timestamps">
<code class="literal">
log_timestamps
</code>
</a>
system
variable controls the time zone of timestamps in messages
written to the error log (as well as to general query log and
slow query log files). The server applies
<a class="link" href="server-system-variables.html#sysvar_log_timestamps">
<code class="literal">
log_timestamps
</code>
</a>
to error
events before they reach any log sink; it thus affects error
message output from all sinks.
</p>
<p>
Permitted
<a class="link" href="server-system-variables.html#sysvar_log_timestamps">
<code class="literal">
log_timestamps
</code>
</a>
values are
<code class="literal">
UTC
</code>
(the default) and
<code class="literal">
SYSTEM
</code>
(the local system time zone).
Timestamps are written using ISO 8601 / RFC 3339 format:
<code class="literal">
<em class="replaceable">
<code>
YYYY-MM-DD
</code>
</em>
T
<em class="replaceable">
<code>
hh:mm:ss.uuuuuu
</code>
</em>
</code>
plus a tail value of
<code class="literal">
Z
</code>
signifying Zulu time
(UTC) or
<code class="literal">
±hh:mm
</code>
(an offset that
indicates the local system time zone adjustment relative to
UTC). For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa21644527"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">2020-08-07T15:02:00.832521Z (UTC)
2020-08-07T10:02:00.832521-05:00 (SYSTEM)</code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/debugging-mysql.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="debugging-mysql">
</a>
7.9 Debugging MySQL
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="debugging-server.html">
7.9.1 Debugging a MySQL Server
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="debugging-client.html">
7.9.2 Debugging a MySQL Client
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="lock-order-tool.html">
7.9.3 The LOCK_ORDER Tool
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="dbug-package.html">
7.9.4 The DBUG Package
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045253862656">
</a>
<a class="indexterm" name="idm46045253861168">
</a>
<p>
This section describes debugging techniques that assist efforts to
track down problems in MySQL.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/information-schema-general-table-reference.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="information-schema-general-table-reference">
</a>
28.3.1 INFORMATION_SCHEMA General Table Reference
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045080547184">
</a>
<a class="indexterm" name="idm46045080545696">
</a>
<p>
The following table summarizes
<code class="literal">
INFORMATION_SCHEMA
</code>
general tables. For greater
detail, see the individual table descriptions.
</p>
<div class="table">
<a name="idm46045080542976">
</a>
<p class="title">
<b>
Table 28.2 INFORMATION_SCHEMA General Tables
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="A reference that lists INFORMATION_SCHEMA general tables.">
<colgroup>
<col style="width: 28%"/>
<col style="width: 71%"/>
</colgroup>
<thead>
<tr>
<th>
Table Name
</th>
<th>
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="information-schema-administrable-role-authorizations-table.html" title="28.3.2 The INFORMATION_SCHEMA ADMINISTRABLE_ROLE_AUTHORIZATIONS Table">
<code class="literal">
ADMINISTRABLE_ROLE_AUTHORIZATIONS
</code>
</a>
</td>
<td>
Grantable users or roles for current user or role
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-applicable-roles-table.html" title="28.3.3 The INFORMATION_SCHEMA APPLICABLE_ROLES Table">
<code class="literal">
APPLICABLE_ROLES
</code>
</a>
</td>
<td>
Applicable roles for current user
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-character-sets-table.html" title="28.3.4 The INFORMATION_SCHEMA CHARACTER_SETS Table">
<code class="literal">
CHARACTER_SETS
</code>
</a>
</td>
<td>
Available character sets
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-check-constraints-table.html" title="28.3.5 The INFORMATION_SCHEMA CHECK_CONSTRAINTS Table">
<code class="literal">
CHECK_CONSTRAINTS
</code>
</a>
</td>
<td>
Table and column CHECK constraints
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-collation-character-set-applicability-table.html" title="28.3.7 The INFORMATION_SCHEMA COLLATION_CHARACTER_SET_APPLICABILITY Table">
<code class="literal">
COLLATION_CHARACTER_SET_APPLICABILITY
</code>
</a>
</td>
<td>
Character set applicable to each collation
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-collations-table.html" title="28.3.6 The INFORMATION_SCHEMA COLLATIONS Table">
<code class="literal">
COLLATIONS
</code>
</a>
</td>
<td>
Collations for each character set
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-column-privileges-table.html" title="28.3.10 The INFORMATION_SCHEMA COLUMN_PRIVILEGES Table">
<code class="literal">
COLUMN_PRIVILEGES
</code>
</a>
</td>
<td>
Privileges defined on columns
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-column-statistics-table.html" title="28.3.11 The INFORMATION_SCHEMA COLUMN_STATISTICS Table">
<code class="literal">
COLUMN_STATISTICS
</code>
</a>
</td>
<td>
Histogram statistics for column values
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-columns-table.html" title="28.3.8 The INFORMATION_SCHEMA COLUMNS Table">
<code class="literal">
COLUMNS
</code>
</a>
</td>
<td>
Columns in each table
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-columns-extensions-table.html" title="28.3.9 The INFORMATION_SCHEMA COLUMNS_EXTENSIONS Table">
<code class="literal">
COLUMNS_EXTENSIONS
</code>
</a>
</td>
<td>
Column attributes for primary and secondary storage engines
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-enabled-roles-table.html" title="28.3.12 The INFORMATION_SCHEMA ENABLED_ROLES Table">
<code class="literal">
ENABLED_ROLES
</code>
</a>
</td>
<td>
Roles enabled within current session
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-engines-table.html" title="28.3.13 The INFORMATION_SCHEMA ENGINES Table">
<code class="literal">
ENGINES
</code>
</a>
</td>
<td>
Storage engine properties
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-events-table.html" title="28.3.14 The INFORMATION_SCHEMA EVENTS Table">
<code class="literal">
EVENTS
</code>
</a>
</td>
<td>
Event Manager events
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-files-table.html" title="28.3.15 The INFORMATION_SCHEMA FILES Table">
<code class="literal">
FILES
</code>
</a>
</td>
<td>
Files that store tablespace data
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-key-column-usage-table.html" title="28.3.16 The INFORMATION_SCHEMA KEY_COLUMN_USAGE Table">
<code class="literal">
KEY_COLUMN_USAGE
</code>
</a>
</td>
<td>
Which key columns have constraints
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-keywords-table.html" title="28.3.17 The INFORMATION_SCHEMA KEYWORDS Table">
<code class="literal">
KEYWORDS
</code>
</a>
</td>
<td>
MySQL keywords
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-ndb-transid-mysql-connection-map-table.html" title="28.3.18 The INFORMATION_SCHEMA ndb_transid_mysql_connection_map Table">
<code class="literal">
ndb_transid_mysql_connection_map
</code>
</a>
</td>
<td>
NDB transaction information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-optimizer-trace-table.html" title="28.3.19 The INFORMATION_SCHEMA OPTIMIZER_TRACE Table">
<code class="literal">
OPTIMIZER_TRACE
</code>
</a>
</td>
<td>
Information produced by optimizer trace activity
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-parameters-table.html" title="28.3.20 The INFORMATION_SCHEMA PARAMETERS Table">
<code class="literal">
PARAMETERS
</code>
</a>
</td>
<td>
Stored routine parameters and stored function return values
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
<code class="literal">
PARTITIONS
</code>
</a>
</td>
<td>
Table partition information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-plugins-table.html" title="28.3.22 The INFORMATION_SCHEMA PLUGINS Table">
<code class="literal">
PLUGINS
</code>
</a>
</td>
<td>
Plugin information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-processlist-table.html" title="28.3.23 The INFORMATION_SCHEMA PROCESSLIST Table">
<code class="literal">
PROCESSLIST
</code>
</a>
</td>
<td>
Information about currently executing threads
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-profiling-table.html" title="28.3.24 The INFORMATION_SCHEMA PROFILING Table">
<code class="literal">
PROFILING
</code>
</a>
</td>
<td>
Statement profiling information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-referential-constraints-table.html" title="28.3.25 The INFORMATION_SCHEMA REFERENTIAL_CONSTRAINTS Table">
<code class="literal">
REFERENTIAL_CONSTRAINTS
</code>
</a>
</td>
<td>
Foreign key information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-resource-groups-table.html" title="28.3.26 The INFORMATION_SCHEMA RESOURCE_GROUPS Table">
<code class="literal">
RESOURCE_GROUPS
</code>
</a>
</td>
<td>
Resource group information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-role-column-grants-table.html" title="28.3.27 The INFORMATION_SCHEMA ROLE_COLUMN_GRANTS Table">
<code class="literal">
ROLE_COLUMN_GRANTS
</code>
</a>
</td>
<td>
Column privileges for roles available to or granted by currently enabled roles
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-role-routine-grants-table.html" title="28.3.28 The INFORMATION_SCHEMA ROLE_ROUTINE_GRANTS Table">
<code class="literal">
ROLE_ROUTINE_GRANTS
</code>
</a>
</td>
<td>
Routine privileges for roles available to or granted by currently enabled roles
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-role-table-grants-table.html" title="28.3.29 The INFORMATION_SCHEMA ROLE_TABLE_GRANTS Table">
<code class="literal">
ROLE_TABLE_GRANTS
</code>
</a>
</td>
<td>
Table privileges for roles available to or granted by currently enabled roles
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-routines-table.html" title="28.3.30 The INFORMATION_SCHEMA ROUTINES Table">
<code class="literal">
ROUTINES
</code>
</a>
</td>
<td>
Stored routine information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-schema-privileges-table.html" title="28.3.33 The INFORMATION_SCHEMA SCHEMA_PRIVILEGES Table">
<code class="literal">
SCHEMA_PRIVILEGES
</code>
</a>
</td>
<td>
Privileges defined on schemas
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-schemata-table.html" title="28.3.31 The INFORMATION_SCHEMA SCHEMATA Table">
<code class="literal">
SCHEMATA
</code>
</a>
</td>
<td>
Schema information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-schemata-extensions-table.html" title="28.3.32 The INFORMATION_SCHEMA SCHEMATA_EXTENSIONS Table">
<code class="literal">
SCHEMATA_EXTENSIONS
</code>
</a>
</td>
<td>
Schema options
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-st-geometry-columns-table.html" title="28.3.35 The INFORMATION_SCHEMA ST_GEOMETRY_COLUMNS Table">
<code class="literal">
ST_GEOMETRY_COLUMNS
</code>
</a>
</td>
<td>
Columns in each table that store spatial data
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-st-spatial-reference-systems-table.html" title="28.3.36 The INFORMATION_SCHEMA ST_SPATIAL_REFERENCE_SYSTEMS Table">
<code class="literal">
ST_SPATIAL_REFERENCE_SYSTEMS
</code>
</a>
</td>
<td>
Available spatial reference systems
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-st-units-of-measure-table.html" title="28.3.37 The INFORMATION_SCHEMA ST_UNITS_OF_MEASURE Table">
<code class="literal">
ST_UNITS_OF_MEASURE
</code>
</a>
</td>
<td>
Acceptable units for ST_Distance()
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-statistics-table.html" title="28.3.34 The INFORMATION_SCHEMA STATISTICS Table">
<code class="literal">
STATISTICS
</code>
</a>
</td>
<td>
Table index statistics
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-table-constraints-table.html" title="28.3.41 The INFORMATION_SCHEMA TABLE_CONSTRAINTS Table">
<code class="literal">
TABLE_CONSTRAINTS
</code>
</a>
</td>
<td>
Which tables have constraints
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-table-constraints-extensions-table.html" title="28.3.42 The INFORMATION_SCHEMA TABLE_CONSTRAINTS_EXTENSIONS Table">
<code class="literal">
TABLE_CONSTRAINTS_EXTENSIONS
</code>
</a>
</td>
<td>
Table constraint attributes for primary and secondary storage engines
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-table-privileges-table.html" title="28.3.43 The INFORMATION_SCHEMA TABLE_PRIVILEGES Table">
<code class="literal">
TABLE_PRIVILEGES
</code>
</a>
</td>
<td>
Privileges defined on tables
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-tables-table.html" title="28.3.38 The INFORMATION_SCHEMA TABLES Table">
<code class="literal">
TABLES
</code>
</a>
</td>
<td>
Table information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-tables-extensions-table.html" title="28.3.39 The INFORMATION_SCHEMA TABLES_EXTENSIONS Table">
<code class="literal">
TABLES_EXTENSIONS
</code>
</a>
</td>
<td>
Table attributes for primary and secondary storage engines
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-tablespaces-extensions-table.html" title="28.3.40 The INFORMATION_SCHEMA TABLESPACES_EXTENSIONS Table">
<code class="literal">
TABLESPACES_EXTENSIONS
</code>
</a>
</td>
<td>
Tablespace attributes for primary storage engines
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-triggers-table.html" title="28.3.44 The INFORMATION_SCHEMA TRIGGERS Table">
<code class="literal">
TRIGGERS
</code>
</a>
</td>
<td>
Trigger information
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-user-attributes-table.html" title="28.3.45 The INFORMATION_SCHEMA USER_ATTRIBUTES Table">
<code class="literal">
USER_ATTRIBUTES
</code>
</a>
</td>
<td>
User comments and attributes
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-user-privileges-table.html" title="28.3.46 The INFORMATION_SCHEMA USER_PRIVILEGES Table">
<code class="literal">
USER_PRIVILEGES
</code>
</a>
</td>
<td>
Privileges defined globally per user
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-view-routine-usage-table.html" title="28.3.48 The INFORMATION_SCHEMA VIEW_ROUTINE_USAGE Table">
<code class="literal">
VIEW_ROUTINE_USAGE
</code>
</a>
</td>
<td>
Stored functions used in views
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-view-table-usage-table.html" title="28.3.49 The INFORMATION_SCHEMA VIEW_TABLE_USAGE Table">
<code class="literal">
VIEW_TABLE_USAGE
</code>
</a>
</td>
<td>
Tables and views used in views
</td>
</tr>
<tr>
<td>
<a class="link" href="information-schema-views-table.html" title="28.3.47 The INFORMATION_SCHEMA VIEWS Table">
<code class="literal">
VIEWS
</code>
</a>
</td>
<td>
View information
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 307.641px;">
Table Name
</th>
<th style="width: 430.359px;">
Description
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/logical-operators.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="logical-operators">
</a>
14.4.3 Logical Operators
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045207007312">
</a>
<a class="indexterm" name="idm46045207006240">
</a>
<div class="table">
<a name="idm46045207004752">
</a>
<p class="title">
<b>
Table 14.5 Logical Operators
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="A reference that lists logical operators.">
<colgroup>
<col style="width: 28%"/>
<col style="width: 71%"/>
</colgroup>
<thead>
<tr>
<th>
Name
</th>
<th>
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="logical-operators.html#operator_and">
<code class="literal">
AND
</code>
,
<code class="literal">
&&
</code>
</a>
</td>
<td>
Logical AND
</td>
</tr>
<tr>
<td>
<a class="link" href="logical-operators.html#operator_not">
<code class="literal">
NOT
</code>
,
<code class="literal">
!
</code>
</a>
</td>
<td>
Negates value
</td>
</tr>
<tr>
<td>
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
OR
</code>
,
<code class="literal">
||
</code>
</a>
</td>
<td>
Logical OR
</td>
</tr>
<tr>
<td>
<a class="link" href="logical-operators.html#operator_xor">
<code class="literal">
XOR
</code>
</a>
</td>
<td>
Logical XOR
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
In SQL, all logical operators evaluate to
<code class="literal">
TRUE
</code>
,
<code class="literal">
FALSE
</code>
, or
<code class="literal">
NULL
</code>
(
<code class="literal">
UNKNOWN
</code>
). In MySQL,
these are implemented as 1 (
<code class="literal">
TRUE
</code>
), 0
(
<code class="literal">
FALSE
</code>
), and
<code class="literal">
NULL
</code>
. Most of
this is common to different SQL database servers, although some
servers may return any nonzero value for
<code class="literal">
TRUE
</code>
.
</p>
<p>
MySQL evaluates any nonzero, non-
<code class="literal">
NULL
</code>
value
to
<code class="literal">
TRUE
</code>
. For example, the following
statements all assess to
<code class="literal">
TRUE
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa9165091"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">10</span> <span class="token operator">IS</span> <span class="token boolean">TRUE</span><span class="token punctuation">;</span>
<span class="token prompt">-></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">-</span><span class="token number">10</span> <span class="token operator">IS</span> <span class="token boolean">TRUE</span><span class="token punctuation">;</span>
<span class="token prompt">-></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token string">'string'</span> <span class="token operator">IS</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt">-></span> <span class="token number">1</span></code></pre>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<a name="operator_not">
</a>
<p>
<a class="link" href="logical-operators.html#operator_not">
<code class="literal">
NOT
</code>
</a>
,
<a class="link" href="logical-operators.html#operator_not">
<code class="literal">
!
</code>
</a>
</p>
<a class="indexterm" name="idm46045206966464">
</a>
<a class="indexterm" name="idm46045206965008">
</a>
<p>
Logical NOT. Evaluates to
<code class="literal">
1
</code>
if the
operand is
<code class="literal">
0
</code>
, to
<code class="literal">
0
</code>
if
the operand is nonzero, and
<code class="literal">
NOT NULL
</code>
returns
<code class="literal">
NULL
</code>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa59266743"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">NOT</span> <span class="token number">10</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">NOT</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token boolean">NULL</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">!</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">!</span> <span class="token number">1</span><span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span></code></pre>
</div>
<p>
The last example produces
<code class="literal">
1
</code>
because the
expression evaluates the same way as
<code class="literal">
(!1)+1
</code>
.
</p>
<p>
The
<a class="link" href="logical-operators.html#operator_not">
<code class="literal">
!
</code>
</a>
operator
is a nonstandard extension, and is deprecated; expect it to
be removed in a future version of MySQL. Applications, where
necessary, should be adjusted to use the standard SQL
<a class="link" href="logical-operators.html#operator_not">
<code class="literal">
NOT
</code>
</a>
operator instead.
</p>
</li>
<li class="listitem">
<a name="operator_and">
</a>
<p>
<a class="link" href="logical-operators.html#operator_and">
<code class="literal">
AND
</code>
</a>
,
<a class="link" href="logical-operators.html#operator_and">
<code class="literal">
&&
</code>
</a>
</p>
<a class="indexterm" name="idm46045206942784">
</a>
<a class="indexterm" name="idm46045206941328">
</a>
<p>
Logical AND. Evaluates to
<code class="literal">
1
</code>
if all
operands are nonzero and not
<code class="literal">
NULL
</code>
, to
<code class="literal">
0
</code>
if one or more operands are
<code class="literal">
0
</code>
, otherwise
<code class="literal">
NULL
</code>
is
returned.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa45032263"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">AND</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">AND</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">AND</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token boolean">NULL</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">0</span> <span class="token operator">AND</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token boolean">NULL</span> <span class="token operator">AND</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span></code></pre>
</div>
<p>
The
<a class="link" href="logical-operators.html#operator_and">
<code class="literal">
&&
</code>
</a>
,
operator is a nonstandard extension and is deprecated;
expect support for it to be removed in a future version of
MySQL. Applications, where necessary, should be adjusted to
use the standard SQL
<a class="link" href="logical-operators.html#operator_and">
<code class="literal">
AND
</code>
</a>
operator instead.
</p>
</li>
<li class="listitem">
<a name="operator_or">
</a>
<p>
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
OR
</code>
</a>
,
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
||
</code>
</a>
</p>
<a class="indexterm" name="idm46045206920880">
</a>
<a class="indexterm" name="idm46045206919424">
</a>
<p>
Logical OR. When both operands are
non-
<code class="literal">
NULL
</code>
, the result is
<code class="literal">
1
</code>
if any operand is nonzero, and
<code class="literal">
0
</code>
otherwise. With a
<code class="literal">
NULL
</code>
operand, the result is
<code class="literal">
1
</code>
if the other operand is nonzero, and
<code class="literal">
NULL
</code>
otherwise. If both operands are
<code class="literal">
NULL
</code>
, the result is
<code class="literal">
NULL
</code>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa69354765"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">OR</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">OR</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">0</span> <span class="token operator">OR</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">0</span> <span class="token operator">OR</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token boolean">NULL</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token operator">OR</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
If the
<a class="link" href="sql-mode.html#sqlmode_pipes_as_concat">
<code class="literal">
PIPES_AS_CONCAT
</code>
</a>
SQL mode is enabled,
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
||
</code>
</a>
signifies
the SQL-standard string concatenation operator (like
<a class="link" href="string-functions.html#function_concat">
<code class="literal">
CONCAT()
</code>
</a>
).
</p>
</div>
<p>
The
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
||
</code>
</a>
, operator
is a nonstandard extension, and is deprecated; expect
support for it to be removed in a future version of MySQL.
Applications, where necessary, should be adjusted to use the
standard SQL
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
OR
</code>
</a>
operator
instead. Exception: Deprecation does not apply if
<a class="link" href="sql-mode.html#sqlmode_pipes_as_concat">
<code class="literal">
PIPES_AS_CONCAT
</code>
</a>
is enabled
because, in that case,
<a class="link" href="logical-operators.html#operator_or">
<code class="literal">
||
</code>
</a>
signifies
string concatenation.
</p>
</li>
<li class="listitem">
<a name="operator_xor">
</a>
<p>
<a class="link" href="logical-operators.html#operator_xor">
<code class="literal">
XOR
</code>
</a>
</p>
<a class="indexterm" name="idm46045206890832">
</a>
<p>
Logical XOR. Returns
<code class="literal">
NULL
</code>
if either
operand is
<code class="literal">
NULL
</code>
. For
non-
<code class="literal">
NULL
</code>
operands, evaluates to
<code class="literal">
1
</code>
if an odd number of operands is
nonzero, otherwise
<code class="literal">
0
</code>
is returned.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa88455011"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token keyword">XOR</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token keyword">XOR</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token keyword">XOR</span> <span class="token boolean">NULL</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token boolean">NULL</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span> <span class="token keyword">XOR</span> <span class="token number">1</span> <span class="token keyword">XOR</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt"> -></span> <span class="token number">1</span></code></pre>
</div>
<p>
<code class="literal">
a XOR b
</code>
is mathematically equal to
<code class="literal">
(a AND (NOT b)) OR ((NOT a) and b)
</code>
.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/installing-development-tree.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="installing-development-tree">
</a>
2.8.5 Installing MySQL Using a Development Source Tree
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045329455920">
</a>
<a class="indexterm" name="idm46045329454848">
</a>
<p>
This section describes how to install MySQL from the latest
development source code, which is hosted on
<a class="ulink" href="https://github.com/" target="_blank">
GitHub
</a>
. To obtain the
MySQL Server source code from this repository hosting service, you
can set up a local MySQL Git repository.
</p>
<p>
On
<a class="ulink" href="https://github.com/" target="_blank">
GitHub
</a>
, MySQL Server
and other MySQL projects are found on the
<a class="ulink" href="https://github.com/mysql" target="_blank">
MySQL
</a>
page. The
MySQL Server project is a single repository that contains branches
for several MySQL series.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="installing-development-tree.html#installing-development-tree-prerequisites" title="Prerequisites for Installing from Development Source">
Prerequisites for Installing from Development Source
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="installing-development-tree.html#installing-development-tree-git" title="Setting Up a MySQL Git Repository">
Setting Up a MySQL Git Repository
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="installing-development-tree-prerequisites">
</a>
Prerequisites for Installing from Development Source
</h4>
</div>
</div>
</div>
<p>
To install MySQL from a development source tree, your system
must satisfy the tool requirements listed at
<a class="xref" href="source-installation-prerequisites.html" title="2.8.2 Source Installation Prerequisites">
Section 2.8.2, “Source Installation Prerequisites”
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="installing-development-tree-git">
</a>
Setting Up a MySQL Git Repository
</h4>
</div>
</div>
</div>
<p>
To set up a MySQL Git repository on your machine:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Clone the MySQL Git repository to your machine. The
following command clones the MySQL Git repository to a
directory named
<code class="filename">
mysql-server
</code>
. The
initial download may take some time to complete, depending
on the speed of your connection.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa61267802"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">git</span> clone https<span class="token punctuation">:</span>//github<span class="token punctuation">.</span>com/mysql/mysql-server<span class="token punctuation">.</span>git
Cloning into <span class="token atrule">'mysql-server'</span><span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span>
remote<span class="token punctuation">:</span> Counting objects<span class="token punctuation">:</span> 1198513<span class="token punctuation">,</span> done<span class="token punctuation">.</span>
remote<span class="token punctuation">:</span> Total 1198513 <span class="token punctuation">(</span>delta 0<span class="token punctuation">)</span><span class="token punctuation">,</span> reused 0 <span class="token punctuation">(</span>delta 0<span class="token punctuation">)</span><span class="token punctuation">,</span> pack-reused 1198513
Receiving objects<span class="token punctuation">:</span> 100% <span class="token punctuation">(</span>1198513/1198513<span class="token punctuation">)</span><span class="token punctuation">,</span> 1<span class="token punctuation">.</span>01 GiB | 7<span class="token punctuation">.</span>44 MiB/s<span class="token punctuation">,</span> done<span class="token punctuation">.</span>
Resolving deltas<span class="token punctuation">:</span> 100% <span class="token punctuation">(</span>993200/993200<span class="token punctuation">)</span><span class="token punctuation">,</span> done<span class="token punctuation">.</span>
Checking connectivity<span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> done<span class="token punctuation">.</span>
Checking out files<span class="token punctuation">:</span> 100% <span class="token punctuation">(</span>25510/25510<span class="token punctuation">)</span><span class="token punctuation">,</span> done<span class="token punctuation">.</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
When the clone operation completes, the contents of your
local MySQL Git repository appear similar to the following:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa14645549"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">~> cd mysql-server
~/mysql-server> ls
client extra mysys storage
cmake include packaging strings
CMakeLists<span class="token punctuation">.</span>txt INSTALL plugin support-files
components libbinlogevents README testclients
config<span class="token punctuation">.</span>h<span class="token punctuation">.</span>cmake libchangestreams router unittest
configure<span class="token punctuation">.</span>cmake libmysql run_doxygen<span class="token punctuation">.</span>cmake utilities
Docs libservices scripts VERSION
Doxyfile-ignored LICENSE share vio
Doxyfile<span class="token punctuation">.</span>in man sql win
doxygen_resources mysql-test sql-common</code></pre>
</div>
</li>
<li class="listitem">
<p>
Use the
<span class="command">
<strong>
git branch -r
</strong>
</span>
command to view the
remote tracking branches for the MySQL repository.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa89084690"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">~/mysql-server> git branch <span class="token property">-r</span>
origin/5<span class="token punctuation">.</span>7
origin/8<span class="token punctuation">.</span>0
origin/HEAD <span class="token property">-></span> origin/trunk
origin/cluster-7<span class="token punctuation">.</span>4
origin/cluster-7<span class="token punctuation">.</span>5
origin/cluster-7<span class="token punctuation">.</span>6
origin/trunk</code></pre>
</div>
</li>
<li class="listitem">
<p>
To view the branch that is checked out in your local
repository, issue the
<span class="command">
<strong>
git branch
</strong>
</span>
command.
When you clone the MySQL Git repository, the latest MySQL
branch is checked out automatically. The asterisk identifies
the active branch.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa59857564"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">~/mysql-server$ </span><span class="token command">git</span> branch
* trunk</code></pre>
</div>
</li>
<li class="listitem">
<p>
To check out an earlier MySQL branch, run the
<span class="command">
<strong>
git
checkout
</strong>
</span>
command, specifying the branch name. For
example, to check out the MySQL 8.0 branch:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa44755329"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">~/mysql-server$ </span><span class="token command">git</span> checkout 8<span class="token punctuation">.</span>0
Checking out files<span class="token punctuation">:</span> 100% <span class="token punctuation">(</span>9600/9600<span class="token punctuation">)</span><span class="token punctuation">,</span> done<span class="token punctuation">.</span>
Branch 8<span class="token punctuation">.</span>0 set up to track remote branch 8<span class="token punctuation">.</span>0 from origin<span class="token punctuation">.</span>
Switched to a new branch <span class="token atrule">'8.0'</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
To obtain changes made after your initial setup of the MySQL
Git repository, switch to the branch you want to update and
issue the
<span class="command">
<strong>
git pull
</strong>
</span>
command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa96108164"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">~/mysql-server$ </span><span class="token command">git</span> checkout trunk
<span class="token prompt">~/mysql-server$ </span><span class="token command">git</span> pull</code></pre>
</div>
<p>
To examine the commit history, use the
<span class="command">
<strong>
git
log
</strong>
</span>
command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa97041530"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">~/mysql-server$ </span><span class="token command">git</span> log</code></pre>
</div>
<p>
You can also browse commit history and source code on the
GitHub
<a class="ulink" href="https://github.com/mysql" target="_blank">
MySQL
</a>
site.
</p>
<p>
If you see changes or code that you have a question about,
ask on
<a class="ulink" href="https://mysqlcommunity.slack.com/" target="_blank">
MySQL
Community Slack
</a>
.
</p>
</li>
<li class="listitem">
<p>
After you have cloned the MySQL Git repository and have
checked out the branch you want to build, you can build
MySQL Server from the source code. Instructions are provided
in
<a class="xref" href="installing-source-distribution.html" title="2.8.4 Installing MySQL Using a Standard Source Distribution">
Section 2.8.4, “Installing MySQL Using a Standard Source Distribution”
</a>
, except
that you skip the part about obtaining and unpacking the
distribution.
</p>
<p>
Be careful about installing a build from a distribution
source tree on a production machine. The installation
command may overwrite your live release installation. If you
already have MySQL installed and do not want to overwrite
it, run
<span class="command">
<strong>
CMake
</strong>
</span>
with values for the
<a class="link" href="source-configuration-options.html#option_cmake_cmake_install_prefix">
<code class="option">
CMAKE_INSTALL_PREFIX
</code>
</a>
,
<a class="link" href="source-configuration-options.html#option_cmake_mysql_tcp_port">
<code class="option">
MYSQL_TCP_PORT
</code>
</a>
, and
<a class="link" href="source-configuration-options.html#option_cmake_mysql_unix_addr">
<code class="option">
MYSQL_UNIX_ADDR
</code>
</a>
options
different from those used by your production server. For
additional information about preventing multiple servers
from interfering with each other, see
<a class="xref" href="multiple-servers.html" title="7.8 Running Multiple MySQL Instances on One Machine">
Section 7.8, “Running Multiple MySQL Instances on One Machine”
</a>
.
</p>
<p>
Play hard with your new installation. For example, try to
make new features crash. Start by running
<span class="command">
<strong>
make
test
</strong>
</span>
. See
<a class="ulink" href="/doc/extending-mysql/8.4/en/mysql-test-suite.html" target="_top">
The MySQL Test Suite
</a>
.
</p>
</li>
</ol>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/innodb-buffer-pool-resize.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="innodb-buffer-pool-resize">
</a>
17.8.3.1 Configuring InnoDB Buffer Pool Size
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045163345680">
</a>
<a class="indexterm" name="idm46045163344608">
</a>
<a class="indexterm" name="idm46045163343536">
</a>
<p>
You can configure
<code class="literal">
InnoDB
</code>
buffer pool size
offline or while the server is running. Behavior described in
this section applies to both methods. For additional information
about configuring buffer pool size online, see
<a class="xref" href="innodb-buffer-pool-resize.html#innodb-buffer-pool-online-resize" title="Configuring InnoDB Buffer Pool Size Online">
Configuring InnoDB Buffer Pool Size Online
</a>
.
</p>
<p>
When increasing or decreasing
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
, the
operation is performed in chunks. Chunk size is defined by the
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
configuration option, which has a default of
<code class="literal">
128M
</code>
. For more information, see
<a class="xref" href="innodb-buffer-pool-resize.html#innodb-buffer-pool-chunk-size" title="Configuring InnoDB Buffer Pool Chunk Size">
Configuring InnoDB Buffer Pool Chunk Size
</a>
.
</p>
<p>
Buffer pool size must always be equal to or a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
If you configure
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
to a
value that is not equal to or a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
,
buffer pool size is automatically adjusted to a value that is
equal to or a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
</p>
<p>
In the following example,
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
is set
to
<code class="literal">
8G
</code>
, and
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
is
set to
<code class="literal">
16
</code>
.
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
is
<code class="literal">
128M
</code>
, which is the default value.
</p>
<p>
<code class="literal">
8G
</code>
is a valid
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
value
because
<code class="literal">
8G
</code>
is a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances=16
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size=128M
</code>
</a>
,
which is
<code class="literal">
2G
</code>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa75179055"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">$> mysqld --innodb-buffer-pool-size<span class="token attr-value"><span class="token punctuation">=</span>8G --innodb-buffer-pool-instances=16</span></code></pre>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96251750"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token operator">/</span><span class="token number">1024</span><span class="token operator">/</span><span class="token number">1024</span><span class="token operator">/</span><span class="token number">1024</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size/1024/1024/1024 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 8.000000000000 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
In this example,
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
is set
to
<code class="literal">
9G
</code>
, and
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
is
set to
<code class="literal">
16
</code>
.
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
is
<code class="literal">
128M
</code>
, which is the default value. In this
case,
<code class="literal">
9G
</code>
is not a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances=16
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size=128M
</code>
</a>
,
so
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
is
adjusted to
<code class="literal">
10G
</code>
, which is a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa70902605"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqld</span> <span class="token constant">--innodb-buffer-pool-size</span><span class="token attr-value"><span class="token punctuation">=</span>9G</span> <span class="token constant">--innodb-buffer-pool-instances</span><span class="token attr-value"><span class="token punctuation">=</span>16</span></code></pre>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa32130612"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token operator">/</span><span class="token number">1024</span><span class="token operator">/</span><span class="token number">1024</span><span class="token operator">/</span><span class="token number">1024</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size/1024/1024/1024 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 10.000000000000 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="innodb-buffer-pool-chunk-size">
</a>
Configuring InnoDB Buffer Pool Chunk Size
</h5>
</div>
</div>
</div>
<p>
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
can be increased or decreased in 1MB (1048576 byte) units but
can only be modified at startup, in a command line string or
in a MySQL configuration file.
</p>
<p>
Command line:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa1092517"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqld</span> <span class="token constant">--innodb-buffer-pool-chunk-size</span><span class="token attr-value"><span class="token punctuation">=</span>134217728</span></code></pre>
</div>
<p>
Configuration file:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa78891726"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">innodb_buffer_pool_chunk_size</span><span class="token attr-value"><span class="token punctuation">=</span>134217728</span></code></pre>
</div>
<p>
The following conditions apply when altering
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If the new
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
value *
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
is larger than the current buffer pool size when the
buffer pool is initialized,
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
is truncated to
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
/
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
</p>
<p>
For example, if the buffer pool is initialized with a size
of
<code class="literal">
2GB
</code>
(2147483648 bytes),
<code class="literal">
4
</code>
buffer pool instances, and a chunk
size of
<code class="literal">
1GB
</code>
(1073741824 bytes), chunk
size is truncated to a value equal to
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
/
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
,
as shown below:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa61026590"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqld</span> <span class="token constant">--innodb-buffer-pool-size</span><span class="token attr-value"><span class="token punctuation">=</span>2147483648</span> <span class="token constant">--innodb-buffer-pool-instances</span><span class="token attr-value"><span class="token punctuation">=</span>4</span>
<span class="token constant">--innodb-buffer-pool-chunk-size</span><span class="token attr-value"><span class="token punctuation">=</span>1073741824;</span></code></pre>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa87489087"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2147483648 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_instances</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_instances <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 4 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># Chunk size was set to 1GB (1073741824 bytes) on startup but was</span>
<span class="token comment" spellcheck="true"># truncated to innodb_buffer_pool_size / innodb_buffer_pool_instances</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_chunk_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_chunk_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 536870912 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Buffer pool size must always be equal to or a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
If you alter
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
,
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
is automatically adjusted to a value that is equal to or a
multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
The adjustment occurs when the buffer pool is initialized.
This behavior is demonstrated in the following example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa65486824"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token comment" spellcheck="true"># The buffer pool has a default size of 128MB (134217728 bytes)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 134217728 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># The chunk size is also 128MB (134217728 bytes)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_chunk_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_chunk_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 134217728 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># There is a single buffer pool instance</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_instances</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_instances <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># Chunk size is decreased by 1MB (1048576 bytes) at startup</span>
<span class="token comment" spellcheck="true"># (134217728 - 1048576 = 133169152):</span>
$<span class="token operator">></span> mysqld <span class="token comment" spellcheck="true">--innodb-buffer-pool-chunk-size=133169152</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_chunk_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_chunk_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 133169152 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># Buffer pool size increases from 134217728 to 266338304</span>
<span class="token comment" spellcheck="true"># Buffer pool size is automatically adjusted to a value that is equal to</span>
<span class="token comment" spellcheck="true"># or a multiple of innodb_buffer_pool_chunk_size * innodb_buffer_pool_instances</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 266338304 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
This example demonstrates the same behavior but with
multiple buffer pool instances:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa56049812"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token comment" spellcheck="true"># The buffer pool has a default size of 2GB (2147483648 bytes)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2147483648 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># The chunk size is .5 GB (536870912 bytes)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_chunk_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_chunk_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 536870912 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># There are 4 buffer pool instances</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_instances</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_instances <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 4 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># Chunk size is decreased by 1MB (1048576 bytes) at startup</span>
<span class="token comment" spellcheck="true"># (536870912 - 1048576 = 535822336):</span>
$<span class="token operator">></span> mysqld <span class="token comment" spellcheck="true">--innodb-buffer-pool-chunk-size=535822336</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_chunk_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_chunk_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 535822336 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token comment" spellcheck="true"># Buffer pool size increases from 2147483648 to 4286578688</span>
<span class="token comment" spellcheck="true"># Buffer pool size is automatically adjusted to a value that is equal to</span>
<span class="token comment" spellcheck="true"># or a multiple of innodb_buffer_pool_chunk_size * innodb_buffer_pool_instances</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@innodb_buffer_pool_size</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@innodb_buffer_pool_size <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 4286578688 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Care should be taken when changing
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
,
as changing this value can increase the size of the buffer
pool, as shown in the examples above. Before you change
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
,
calculate the effect on
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
to ensure that the resulting buffer pool size is
acceptable.
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
To avoid potential performance issues, the number of chunks
(
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
/
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
)
should not exceed 1000.
</p>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="innodb-buffer-pool-online-resize">
</a>
Configuring InnoDB Buffer Pool Size Online
</h5>
</div>
</div>
</div>
<p>
The
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_size">
<code class="literal">
innodb_buffer_pool_size
</code>
</a>
configuration option can be set dynamically using a
<a class="link" href="set.html" title="13.3.6 The SET Type">
<code class="literal">
SET
</code>
</a>
statement, allowing you to
resize the buffer pool without restarting the server. For
example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa72992094"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> innodb_buffer_pool_size<span class="token operator">=</span><span class="token number">402653184</span><span class="token punctuation">;</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The buffer pool size must be equal to or a multiple of
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
*
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_instances">
<code class="literal">
innodb_buffer_pool_instances
</code>
</a>
.
Changing those variable settings requires restarting the
server.
</p>
</div>
<p>
Active transactions and operations performed through
<code class="literal">
InnoDB
</code>
APIs should be completed before
resizing the buffer pool. When initiating a resizing
operation, the operation does not start until all active
transactions are completed. Once the resizing operation is in
progress, new transactions and operations that require access
to the buffer pool must wait until the resizing operation
finishes. The exception to the rule is that concurrent access
to the buffer pool is permitted while the buffer pool is
defragmented and pages are withdrawn when buffer pool size is
decreased. A drawback of allowing concurrent access is that it
could result in a temporary shortage of available pages while
pages are being withdrawn.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Nested transactions could fail if initiated after the buffer
pool resizing operation begins.
</p>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="innodb-buffer-pool-online-resize-monitoring">
</a>
Monitoring Online Buffer Pool Resizing Progress
</h5>
</div>
</div>
</div>
<a class="indexterm" name="idm46045163217344">
</a>
<a class="indexterm" name="idm46045163215856">
</a>
<p>
The
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status">
<code class="literal">
Innodb_buffer_pool_resize_status
</code>
</a>
variable reports a string value indicating buffer pool
resizing progress; for example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa7300427"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">STATUS</span> <span class="token keyword">WHERE</span> Variable_name<span class="token operator">=</span><span class="token string">'InnoDB_buffer_pool_resize_status'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Variable_name <span class="token punctuation">|</span> Value <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Innodb_buffer_pool_resize_status <span class="token punctuation">|</span> Resizing also other hash tables. <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
You can also monitor an online buffer pool resizing operation
using the
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_code">
<code class="literal">
Innodb_buffer_pool_resize_status_code
</code>
</a>
and
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_progress">
<code class="literal">
Innodb_buffer_pool_resize_status_progress
</code>
</a>
status variables, which report numeric values, preferable for
programmatic monitoring.
</p>
<p>
The
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_code">
<code class="literal">
Innodb_buffer_pool_resize_status_code
</code>
</a>
status variable reports a status code indicating the stage of
an online buffer pool resizing operation. Status codes
include:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
0: No Resize operation in progress
</p>
</li>
<li class="listitem">
<p>
1: Starting Resize
</p>
</li>
<li class="listitem">
<p>
2: Disabling AHI (Adaptive Hash Index)
</p>
</li>
<li class="listitem">
<p>
3: Withdrawing Blocks
</p>
</li>
<li class="listitem">
<p>
4: Acquiring Global Lock
</p>
</li>
<li class="listitem">
<p>
5: Resizing Pool
</p>
</li>
<li class="listitem">
<p>
6: Resizing Hash
</p>
</li>
<li class="listitem">
<p>
7: Resizing Failed
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_progress">
<code class="literal">
Innodb_buffer_pool_resize_status_progress
</code>
</a>
status variable reports a percentage value indicating the
progress of each stage. The percentage value is updated after
each buffer pool instance is processed. As the status
(reported by
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_code">
<code class="literal">
Innodb_buffer_pool_resize_status_code
</code>
</a>
)
changes from one status to another, the percentage value is
reset to 0.
</p>
<p>
The following query returns a string value indicating the
buffer pool resizing progress, a code indicating the current
stage of the operation, and the current progress of that
stage, expressed as a percentage value:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa3829440"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> variable_name<span class="token punctuation">,</span> variable_value
<span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>global_status
<span class="token keyword">WHERE</span> <span class="token function">LOWER</span><span class="token punctuation">(</span>variable_name<span class="token punctuation">)</span> <span class="token operator">LIKE</span> <span class="token string">"innodb_buffer_pool_resize%"</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Buffer pool resizing progress is also visible in the server
error log. This example shows notes that are logged when
increasing the size of the buffer pool:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa85121534"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> Resizing buffer pool from 134217728 to 4294967296<span class="token punctuation">.</span> <span class="token punctuation">(</span>unit<span class="token attr-value"><span class="token punctuation">=</span>134217728)</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> disabled adaptive hash index<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> 31 chunks <span class="token punctuation">(</span>253952 blocks<span class="token punctuation">)</span> was added<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> hash tables were resized<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> Resized hash tables at lock_sys<span class="token punctuation">,</span> adaptive hash index<span class="token punctuation">,</span> dictionary<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> completed to resize buffer pool from 134217728 to 4294967296<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> re-enabled adaptive hash index<span class="token punctuation">.</span></code></pre>
</div>
<p>
This example shows notes that are logged when decreasing the
size of the buffer pool:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa51265137"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> Resizing buffer pool from 4294967296 to 134217728<span class="token punctuation">.</span> <span class="token punctuation">(</span>unit<span class="token attr-value"><span class="token punctuation">=</span>134217728)</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> disabled adaptive hash index<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> start to withdraw the last 253952 blocks<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> withdrew 253952 blocks from free list<span class="token punctuation">.</span> tried to relocate
0 pages<span class="token punctuation">.</span> <span class="token punctuation">(</span>253952/253952<span class="token punctuation">)</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> withdrawn target 253952 blocks<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> 31 chunks <span class="token punctuation">(</span>253952 blocks<span class="token punctuation">)</span> was freed<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> hash tables were resized<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> Resized hash tables at lock_sys<span class="token punctuation">,</span> adaptive hash index<span class="token punctuation">,</span> dictionary<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> completed to resize buffer pool from 4294967296 to 134217728<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> InnoDB<span class="token punctuation">:</span> re-enabled adaptive hash index<span class="token punctuation">.</span></code></pre>
</div>
<p>
Starting the server with
<a class="link" href="server-system-variables.html#sysvar_log_error_verbosity">
<code class="literal">
--log-error-verbosity=3
</code>
</a>
logs
additional information to the error log during an online
buffer pool resizing operation. Additional information
includes the status codes reported by
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_code">
<code class="literal">
Innodb_buffer_pool_resize_status_code
</code>
</a>
and the percentage progress value reported by
<a class="link" href="server-status-variables.html#statvar_Innodb_buffer_pool_resize_status_progress">
<code class="literal">
Innodb_buffer_pool_resize_status_progress
</code>
</a>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa2522891"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-012398<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Requested to resize buffer pool<span class="token punctuation">.</span> <span class="token punctuation">(</span>new size<span class="token punctuation">:</span> 1073741824 bytes<span class="token punctuation">)</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 1<span class="token punctuation">:</span> Resizing buffer pool from 134217728 to 1073741824
<span class="token punctuation">(</span>unit<span class="token attr-value"><span class="token punctuation">=</span>134217728).</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 1<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 1<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 2<span class="token punctuation">:</span> Disabling adaptive hash index<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011885<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> disabled adaptive hash index<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 2<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 2<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 3<span class="token punctuation">:</span> Withdrawing blocks to be shrunken<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 3<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 3<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> Latching whole of buffer pool<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 14% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 28% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 42% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 57% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 71% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 85% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 4<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 5<span class="token punctuation">:</span> Starting pool resize
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 5<span class="token punctuation">:</span> buffer pool 0 <span class="token punctuation">:</span> resizing with chunks 1 to 8<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011891<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> buffer pool 0 <span class="token punctuation">:</span> 7 chunks <span class="token punctuation">(</span>57339 blocks<span class="token punctuation">)</span> were added<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 5<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 5<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 6<span class="token punctuation">:</span> Resizing hash tables<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011892<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> buffer pool 0 <span class="token punctuation">:</span> hash tables were resized<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 6<span class="token punctuation">:</span> 100% complete
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 6<span class="token punctuation">:</span> Resizing also other hash tables<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011893<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Resized hash tables at lock_sys<span class="token punctuation">,</span> adaptive hash index<span class="token punctuation">,</span> dictionary<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011894<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Completed to resize buffer pool from 134217728 to 1073741824<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-011895<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Re-enabled adaptive hash index<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013952<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 6<span class="token punctuation">:</span> Completed
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013954<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 0<span class="token punctuation">:</span> Completed resizing buffer pool at 220826 6<span class="token punctuation">:</span>25<span class="token punctuation">:</span>46<span class="token punctuation">.</span>
<span class="token punctuation">[</span>Note<span class="token punctuation">]</span> <span class="token punctuation">[</span>MY-013953<span class="token punctuation">]</span> <span class="token punctuation">[</span>InnoDB<span class="token punctuation">]</span> Status code 0<span class="token punctuation">:</span> 100% complete</code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="innodb-buffer-pool-online-resize-internals">
</a>
Online Buffer Pool Resizing Internals
</h5>
</div>
</div>
</div>
<p>
The resizing operation is performed by a background thread.
When increasing the size of the buffer pool, the resizing
operation:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Adds pages in
<code class="literal">
chunks
</code>
(chunk size is
defined by
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
)
</p>
</li>
<li class="listitem">
<p>
Converts hash tables, lists, and pointers to use new
addresses in memory
</p>
</li>
<li class="listitem">
<p>
Adds new pages to the free list
</p>
</li>
</ul>
</div>
<p>
While these operations are in progress, other threads are
blocked from accessing the buffer pool.
</p>
<p>
When decreasing the size of the buffer pool, the resizing
operation:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Defragments the buffer pool and withdraws (frees) pages
</p>
</li>
<li class="listitem">
<p>
Removes pages in
<code class="literal">
chunks
</code>
(chunk size is
defined by
<a class="link" href="innodb-parameters.html#sysvar_innodb_buffer_pool_chunk_size">
<code class="literal">
innodb_buffer_pool_chunk_size
</code>
</a>
)
</p>
</li>
<li class="listitem">
<p>
Converts hash tables, lists, and pointers to use new
addresses in memory
</p>
</li>
</ul>
</div>
<p>
Of these operations, only defragmenting the buffer pool and
withdrawing pages allow other threads to access to the buffer
pool concurrently.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-ps-setup-show-enabled-consumers.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-ps-setup-show-enabled-consumers">
</a>
30.4.4.19 The ps_setup_show_enabled_consumers() Procedure
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045061327120">
</a>
<a class="indexterm" name="idm46045061325600">
</a>
<p>
Displays all currently enabled Performance Schema consumers.
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-setup-show-enabled-consumers-parameters">
</a>
Parameters
</h5>
</div>
</div>
</div>
<p>
None.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-setup-show-enabled-consumers-example">
</a>
Example
</h5>
</div>
</div>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa86155206"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CALL</span> sys<span class="token punctuation">.</span>ps_setup_show_enabled_consumers<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> enabled_consumers <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> events_statements_current <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> events_statements_history <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> events_transactions_current <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> events_transactions_history <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> global_instrumentation <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> statements_digest <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> thread_instrumentation <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-schema-unused-indexes.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-schema-unused-indexes">
</a>
30.4.3.32 The schema_unused_indexes View
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045062267712">
</a>
<a class="indexterm" name="idm46045062266208">
</a>
<p>
These views display indexes for which there are no events,
which indicates that they are not being used. By default, rows
are sorted by schema and table.
</p>
<p>
This view is most useful when the server has been up and
processing long enough that its workload is representative.
Otherwise, presence of an index in this view may not be
meaningful.
</p>
<p>
The
<a class="link" href="sys-schema-unused-indexes.html" title="30.4.3.32 The schema_unused_indexes View">
<code class="literal">
schema_unused_indexes
</code>
</a>
view
has these columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
object_schema
</code>
</p>
<p>
The schema name.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
object_name
</code>
</p>
<p>
The table name.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
index_name
</code>
</p>
<p>
The unused index name.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-howto-masterstatus.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-howto-masterstatus">
</a>
19.1.2.4 Obtaining the Replication Source Binary Log Coordinates
</h4>
</div>
</div>
</div>
<p>
To configure the replica to start the replication process at the
correct point, you need to note the source's current coordinates
within its binary log.
</p>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
This procedure uses
<a class="link" href="flush.html#flush-tables-with-read-lock">
<code class="literal">
FLUSH TABLES WITH
READ LOCK
</code>
</a>
, which blocks
<a class="link" href="commit.html" title="15.3.1 START TRANSACTION, COMMIT, and ROLLBACK Statements">
<code class="literal">
COMMIT
</code>
</a>
operations for
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
tables.
</p>
</div>
<p>
If you are planning to shut down the source to create a data
snapshot, you can optionally skip this procedure and instead
store a copy of the binary log index file along with the data
snapshot. In that situation, the source creates a new binary log
file on restart. The source binary log coordinates where the
replica must start the replication process are therefore the
start of that new file, which is the next binary log file on the
source following after the files that are listed in the copied
binary log index file.
</p>
<p>
To obtain the source binary log coordinates, follow these steps:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Start a session on the source by connecting to it with the
command-line client, and flush all tables and block write
statements by executing the
<a class="link" href="flush.html#flush-tables-with-read-lock">
<code class="literal">
FLUSH
TABLES WITH READ LOCK
</code>
</a>
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa27580345"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">FLUSH</span> <span class="token keyword">TABLES</span> <span class="token keyword">WITH</span> <span class="token keyword">READ</span> <span class="token keyword">LOCK</span><span class="token punctuation">;</span></code></pre>
</div>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
Leave the client from which you issued the
<a class="link" href="flush.html#flush-tables">
<code class="literal">
FLUSH TABLES
</code>
</a>
statement
running so that the read lock remains in effect. If you
exit the client, the lock is released.
</p>
</div>
</li>
<li class="listitem">
<p>
In a different session on the source, use the
<a class="link" href="show-binary-log-status.html" title="15.7.7.1 SHOW BINARY LOG STATUS Statement">
<code class="literal">
SHOW BINARY LOG STATUS
</code>
</a>
statement to determine the current binary log file name and
position:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa68446605"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token datatype">BINARY</span> LOG <span class="token keyword">STATUS</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
File<span class="token punctuation">:</span> mysql-bin.000003
Position<span class="token punctuation">:</span> 73
Binlog_Do_DB<span class="token punctuation">:</span> test
Binlog_Ignore_DB<span class="token punctuation">:</span> manual, mysql
Executed_Gtid_Set<span class="token punctuation">:</span> 3E11FA47-71CA-11E1-9E33-C80AA9429562<span class="token punctuation">:</span>1-5
</span><span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
The
<code class="literal">
File
</code>
column shows the name of the log
file and the
<code class="literal">
Position
</code>
column shows the
position within the file. In this example, the binary log
file is
<code class="literal">
mysql-bin.000003
</code>
and the position
is 73. Record these values. You need them later when you are
setting up the replica. They represent the replication
coordinates at which the replica should begin processing new
updates from the source.
</p>
<p>
If the source has been running previously with binary
logging disabled, the log file name and position values
displayed by
<a class="link" href="show-binary-log-status.html" title="15.7.7.1 SHOW BINARY LOG STATUS Statement">
<code class="literal">
SHOW BINARY LOG
STATUS
</code>
</a>
or
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
<a class="link" href="mysqldump.html#option_mysqldump_source-data">
<code class="option">
--source-data
</code>
</a>
are empty.
In that case, the values that you need to use later when
specifying the source's binary log file and position
are the empty string (
<code class="literal">
''
</code>
) and
<code class="literal">
4
</code>
.
</p>
</li>
</ol>
</div>
<p>
You now have the information you need to enable the replica to
start reading from the source's binary log in the correct
place to start replication.
</p>
<p>
The next step depends on whether you have existing data on the
source. Choose one of the following options:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If you have existing data that needs be to synchronized with
the replica before you start replication, leave the client
running so that the lock remains in place. This prevents any
further changes being made, so that the data copied to the
replica is in synchrony with the source. Proceed to
<a class="xref" href="replication-snapshot-method.html" title="19.1.2.5 Choosing a Method for Data Snapshots">
Section 19.1.2.5, “Choosing a Method for Data Snapshots”
</a>
.
</p>
</li>
<li class="listitem">
<p>
If you are setting up a new source and replica combination,
you can exit the first session to release the read lock. See
<a class="xref" href="replication-setup-replicas.html#replication-howto-newservers" title="19.1.2.6.1 Setting Up Replication with New Source and Replicas">
Section 19.1.2.6.1, “Setting Up Replication with New Source and Replicas”
</a>
for how to
proceed.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/integer-types.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="integer-types">
</a>
13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT,
MEDIUMINT, BIGINT
</h3>
</div>
</div>
</div>
<p>
MySQL supports the SQL standard integer types
<code class="literal">
INTEGER
</code>
(or
<code class="literal">
INT
</code>
) and
<code class="literal">
SMALLINT
</code>
. As an extension to the standard,
MySQL also supports the integer types
<code class="literal">
TINYINT
</code>
,
<code class="literal">
MEDIUMINT
</code>
, and
<code class="literal">
BIGINT
</code>
. The following table shows the
required storage and range for each integer type.
</p>
<div class="table">
<a name="integer-type-storage-and-range">
</a>
<p class="title">
<b>
Table 13.1 Required Storage and Range for Integer Types Supported by MySQL
</b>
</p>
<div class="table-contents">
<table summary="Required storage and range for integer types supported by MySQL. Information includes the integer type, the storage size in bytes, the minimum signed and unsigned values, and the maximum signed and unsigned values.">
<colgroup>
<col style="width: 16%"/>
<col style="width: 16%"/>
<col style="width: 16%"/>
<col style="width: 16%"/>
<col style="width: 16%"/>
<col style="width: 16%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Type
</th>
<th scope="col">
Storage (Bytes)
</th>
<th scope="col">
Minimum Value Signed
</th>
<th scope="col">
Minimum Value Unsigned
</th>
<th scope="col">
Maximum Value Signed
</th>
<th scope="col">
Maximum Value Unsigned
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<code class="literal">
TINYINT
</code>
</th>
<td>
1
</td>
<td>
<code class="literal">
-128
</code>
</td>
<td>
<code class="literal">
0
</code>
</td>
<td>
<code class="literal">
127
</code>
</td>
<td>
<code class="literal">
255
</code>
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
SMALLINT
</code>
</th>
<td>
2
</td>
<td>
<code class="literal">
-32768
</code>
</td>
<td>
<code class="literal">
0
</code>
</td>
<td>
<code class="literal">
32767
</code>
</td>
<td>
<code class="literal">
65535
</code>
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
MEDIUMINT
</code>
</th>
<td>
3
</td>
<td>
<code class="literal">
-8388608
</code>
</td>
<td>
<code class="literal">
0
</code>
</td>
<td>
<code class="literal">
8388607
</code>
</td>
<td>
<code class="literal">
16777215
</code>
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
INT
</code>
</th>
<td>
4
</td>
<td>
<code class="literal">
-2147483648
</code>
</td>
<td>
<code class="literal">
0
</code>
</td>
<td>
<code class="literal">
2147483647
</code>
</td>
<td>
<code class="literal">
4294967295
</code>
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
BIGINT
</code>
</th>
<td>
8
</td>
<td>
<code class="literal">
-2
<sup>
63
</sup>
</code>
</td>
<td>
<code class="literal">
0
</code>
</td>
<td>
<code class="literal">
2
<sup>
63
</sup>
-1
</code>
</td>
<td>
<code class="literal">
2
<sup>
64
</sup>
-1
</code>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/time-zone-support.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="time-zone-support">
</a>
7.1.15 MySQL Server Time Zone Support
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045260470800">
</a>
<p>
This section describes the time zone settings maintained by MySQL,
how to load the system tables required for named time support, how
to stay current with time zone changes, and how to enable
leap-second support.
</p>
<p>
Time zone offsets are also supported for inserted datetime values;
see
<a class="xref" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
Section 13.2.2, “The DATE, DATETIME, and TIMESTAMP Types”
</a>
, for more information.
</p>
<p>
For information about time zone settings in replication setups,
see
<a class="xref" href="replication-features-functions.html" title="19.5.1.14 Replication and System Functions">
Section 19.5.1.14, “Replication and System Functions”
</a>
and
<a class="xref" href="replication-features-timezone.html" title="19.5.1.33 Replication and Time Zones">
Section 19.5.1.33, “Replication and Time Zones”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="time-zone-support.html#time-zone-variables" title="Time Zone Variables">
Time Zone Variables
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="time-zone-support.html#time-zone-installation" title="Populating the Time Zone Tables">
Populating the Time Zone Tables
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="time-zone-support.html#time-zone-upgrades" title="Staying Current with Time Zone Changes">
Staying Current with Time Zone Changes
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="time-zone-support.html#time-zone-leap-seconds" title="Time Zone Leap Second Support">
Time Zone Leap Second Support
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="time-zone-variables">
</a>
Time Zone Variables
</h4>
</div>
</div>
</div>
<p>
MySQL Server maintains several time zone settings:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The server system time zone. When the server starts, it
attempts to determine the time zone of the host machine and
uses it to set the
<a class="link" href="server-system-variables.html#sysvar_system_time_zone">
<code class="literal">
system_time_zone
</code>
</a>
system
variable.
</p>
<a class="indexterm" name="idm46045260456960">
</a>
<a class="indexterm" name="idm46045260455872">
</a>
<a class="indexterm" name="idm46045260454384">
</a>
<a class="indexterm" name="idm46045260453312">
</a>
<p>
To explicitly specify the system time zone for MySQL Server
at startup, set the
<code class="literal">
TZ
</code>
environment
variable before you start
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
. If you
start the server using
<a class="link" href="mysqld-safe.html" title="6.3.2 mysqld_safe — MySQL Server Startup Script">
<span class="command">
<strong>
mysqld_safe
</strong>
</span>
</a>
, its
<a class="link" href="mysqld-safe.html#option_mysqld_safe_timezone">
<code class="option">
--timezone
</code>
</a>
option
provides another way to set the system time zone. The
permissible values for
<code class="literal">
TZ
</code>
and
<a class="link" href="mysqld-safe.html#option_mysqld_safe_timezone">
<code class="option">
--timezone
</code>
</a>
are system
dependent. Consult your operating system documentation to
see what values are acceptable.
</p>
</li>
<li class="listitem">
<p>
The server current time zone. The global
<a class="link" href="server-system-variables.html#sysvar_time_zone">
<code class="literal">
time_zone
</code>
</a>
system variable
indicates the time zone the server currently is operating
in. The initial
<a class="link" href="server-system-variables.html#sysvar_time_zone">
<code class="literal">
time_zone
</code>
</a>
value is
<code class="literal">
'SYSTEM'
</code>
, which indicates that
the server time zone is the same as the system time zone.
</p>
<a class="indexterm" name="idm46045260441024">
</a>
<a class="indexterm" name="idm46045260439936">
</a>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
If set to
<code class="literal">
SYSTEM
</code>
, every MySQL function
call that requires a time zone calculation makes a system
library call to determine the current system time zone.
This call may be protected by a global mutex, resulting in
contention.
</p>
</div>
<p>
The initial global server time zone value can be specified
explicitly at startup with the
<a class="link" href="server-options.html#option_mysqld_default-time-zone">
<code class="option">
--default-time-zone
</code>
</a>
option on
the command line, or you can use the following line in an
option file:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa34247275"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">default-time-zone</span><span class="token attr-value"><span class="token punctuation">=</span>'<em class="replaceable">timezone</em>'</span></code></pre>
</div>
<p>
If you have the
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
privilege (or the deprecated
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege), you can set
the global server time zone value at runtime with this
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa97711435"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> time_zone <span class="token operator">=</span> <em class="replaceable">timezone</em><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Per-session time zones. Each client that connects has its
own session time zone setting, given by the session
<a class="link" href="server-system-variables.html#sysvar_time_zone">
<code class="literal">
time_zone
</code>
</a>
variable.
Initially, the session variable takes its value from the
global
<a class="link" href="server-system-variables.html#sysvar_time_zone">
<code class="literal">
time_zone
</code>
</a>
variable,
but the client can change its own time zone with this
statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa78304308"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> time_zone <span class="token operator">=</span> <em class="replaceable">timezone</em><span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
The session time zone setting affects display and storage of
time values that are zone-sensitive. This includes the values
displayed by functions such as
<a class="link" href="date-and-time-functions.html#function_now">
<code class="literal">
NOW()
</code>
</a>
or
<a class="link" href="date-and-time-functions.html#function_curtime">
<code class="literal">
CURTIME()
</code>
</a>
, and values stored in
and retrieved from
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
columns. Values for
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
columns are converted from the session time zone to UTC for
storage, and from UTC to the session time zone for retrieval.
</p>
<p>
The session time zone setting does not affect values displayed
by functions such as
<a class="link" href="date-and-time-functions.html#function_utc-timestamp">
<code class="literal">
UTC_TIMESTAMP()
</code>
</a>
or values in
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
DATE
</code>
</a>
,
<a class="link" href="time.html" title="13.2.3 The TIME Type">
<code class="literal">
TIME
</code>
</a>
, or
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
DATETIME
</code>
</a>
columns. Nor are values
in those data types stored in UTC; the time zone applies for
them only when converting from
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
values. If you want
locale-specific arithmetic for
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
DATE
</code>
</a>
,
<a class="link" href="time.html" title="13.2.3 The TIME Type">
<code class="literal">
TIME
</code>
</a>
, or
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
DATETIME
</code>
</a>
values, convert them to
UTC, perform the arithmetic, and then convert back.
</p>
<p>
The current global and session time zone values can be retrieved
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa33667617"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token variable">@@GLOBAL.time_zone</span><span class="token punctuation">,</span> <span class="token variable">@@SESSION.time_zone</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
<em class="replaceable">
<code>
timezone
</code>
</em>
values can be given in
several formats, none of which are case-sensitive:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
As the value
<code class="literal">
'SYSTEM'
</code>
, indicating that
the server time zone is the same as the system time zone.
</p>
</li>
<li class="listitem">
<p>
As a string indicating an offset from UTC of the form
<code class="literal">
[
<em class="replaceable">
<code>
H
</code>
</em>
]
<em class="replaceable">
<code>
H
</code>
</em>
:
<em class="replaceable">
<code>
MM
</code>
</em>
</code>
,
prefixed with a
<code class="literal">
+
</code>
or
<code class="literal">
-
</code>
, such as
<code class="literal">
'+10:00'
</code>
,
<code class="literal">
'-6:00'
</code>
, or
<code class="literal">
'+05:30'
</code>
.
A leading zero can optionally be used for hours values less
than 10; MySQL prepends a leading zero when storing and
retrieving the value in such cases. MySQL converts
<code class="literal">
'-00:00'
</code>
or
<code class="literal">
'-0:00'
</code>
to
<code class="literal">
'+00:00'
</code>
.
</p>
<p>
This value must be in the range
<code class="literal">
'-13:59'
</code>
to
<code class="literal">
'+14:00'
</code>
, inclusive.
</p>
</li>
<li class="listitem">
<p>
As a named time zone, such as
<code class="literal">
'Europe/Helsinki'
</code>
,
<code class="literal">
'US/Eastern'
</code>
,
<code class="literal">
'MET'
</code>
,
or
<code class="literal">
'UTC'
</code>
.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Named time zones can be used only if the time zone
information tables in the
<code class="literal">
mysql
</code>
database have been created and populated. Otherwise, use
of a named time zone results in an error:
</p>
<a class="indexterm" name="idm46045260387536">
</a>
<a class="indexterm" name="idm46045260386032">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa3914316"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> time_zone <span class="token operator">=</span> <span class="token string">'UTC'</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1298 (HY000)<span class="token punctuation">:</span> Unknown or incorrect time zone<span class="token punctuation">:</span> 'UTC'</span></code></pre>
</div>
</div>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="time-zone-installation">
</a>
Populating the Time Zone Tables
</h4>
</div>
</div>
</div>
<p>
Several tables in the
<code class="literal">
mysql
</code>
system schema
exist to store time zone information (see
<a class="xref" href="system-schema.html" title="7.3 The mysql System Schema">
Section 7.3, “The mysql System Schema”
</a>
). The MySQL installation
procedure creates the time zone tables, but does not load them.
To do so manually, use the following instructions.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Loading the time zone information is not necessarily a
one-time operation because the information changes
occasionally. When such changes occur, applications that use
the old rules become out of date and you may find it necessary
to reload the time zone tables to keep the information used by
your MySQL server current. See
<a class="xref" href="time-zone-support.html#time-zone-upgrades" title="Staying Current with Time Zone Changes">
Staying Current with Time Zone Changes
</a>
.
</p>
</div>
<p>
If your system has its own
<span class="firstterm">
zoneinfo
</span>
database (the set
of files describing time zones), use the
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
program to load the time
zone tables. Examples of such systems are Linux, macOS, FreeBSD,
and Solaris. One likely location for these files is the
<code class="filename">
/usr/share/zoneinfo
</code>
directory. If your
system has no zoneinfo database, you can use a downloadable
package, as described later in this section.
</p>
<p>
To load the time zone tables from the command line, pass the
zoneinfo directory path name to
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
and send the output into
the
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
program. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa53835569"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql <span class="token property">-u</span> root <span class="token property">-p</span> mysql</code></pre>
</div>
<p>
The
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
command shown here assumes that you
connect to the server using an account such as
<code class="literal">
root
</code>
that has privileges for modifying tables
in the
<code class="literal">
mysql
</code>
system schema. Adjust the
connection parameters as required.
</p>
<p>
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
reads your system's time
zone files and generates SQL statements from them.
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
processes those statements to load the
time zone tables.
</p>
<p>
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
also can be used to load
a single time zone file or generate leap second information:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
To load a single time zone file
<em class="replaceable">
<code>
tz_file
</code>
</em>
that corresponds to a
time zone name
<em class="replaceable">
<code>
tz_name
</code>
</em>
, invoke
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa71338347"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysql_tzinfo_to_sql <em class="replaceable">tz_file</em> <em class="replaceable">tz_name</em> | mysql <span class="token property">-u</span> root <span class="token property">-p</span> mysql</code></pre>
</div>
<p>
With this approach, you must execute a separate command to
load the time zone file for each named zone that the server
needs to know about.
</p>
</li>
<li class="listitem">
<p>
If your time zone must account for leap seconds, initialize
leap second information like this, where
<em class="replaceable">
<code>
tz_file
</code>
</em>
is the name of your time
zone file:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa89093648"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysql_tzinfo_to_sql <span class="token property">--leap</span> <em class="replaceable">tz_file</em> | mysql <span class="token property">-u</span> root <span class="token property">-p</span> mysql</code></pre>
</div>
</li>
</ul>
</div>
<p>
After running
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
, restart
the server so that it does not continue to use any previously
cached time zone data.
</p>
<p>
If your system has no zoneinfo database (for example, Windows),
you can use a package containing SQL statements that is
available for download at the MySQL Developer Zone:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa7767967"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple">https<span class="token operator">:</span><span class="token operator">/</span><span class="token operator">/</span>dev<span class="token punctuation">.</span>mysql<span class="token punctuation">.</span>com<span class="token operator">/</span>downloads<span class="token operator">/</span>timezones<span class="token punctuation">.</span>html</code></pre>
</div>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
Do
<span class="emphasis">
<em>
not
</em>
</span>
use a downloadable time zone
package if your system has a zoneinfo database. Use the
<a class="link" href="mysql-tzinfo-to-sql.html" title="6.4.3 mysql_tzinfo_to_sql — Load the Time Zone Tables">
<span class="command">
<strong>
mysql_tzinfo_to_sql
</strong>
</span>
</a>
utility instead.
Otherwise, you may cause a difference in datetime handling
between MySQL and other applications on your system.
</p>
</div>
<p>
To use an SQL-statement time zone package that you have
downloaded, unpack it, then load the unpacked file contents into
the time zone tables:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa4033101"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysql <span class="token property">-u</span> root <span class="token property">-p</span> mysql < <em class="replaceable">file_name</em></code></pre>
</div>
<p>
Then restart the server.
</p>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
Do
<span class="emphasis">
<em>
not
</em>
</span>
use a downloadable time zone
package that contains
<code class="literal">
MyISAM
</code>
tables. That
is intended for older MySQL versions. MySQL now uses
<code class="literal">
InnoDB
</code>
for the time zone tables. Trying to
replace them with
<code class="literal">
MyISAM
</code>
tables causes
problems.
</p>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="time-zone-upgrades">
</a>
Staying Current with Time Zone Changes
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045260338784">
</a>
<p>
When time zone rules change, applications that use the old rules
become out of date. To stay current, it is necessary to make
sure that your system uses current time zone information is
used. For MySQL, there are multiple factors to consider in
staying current:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The operating system time affects the value that the MySQL
server uses for times if its time zone is set to
<code class="literal">
SYSTEM
</code>
. Make sure that your operating
system is using the latest time zone information. For most
operating systems, the latest update or service pack
prepares your system for the time changes. Check the website
for your operating system vendor for an update that
addresses the time changes.
</p>
</li>
<li class="listitem">
<p>
If you replace the system's
<code class="filename">
/etc/localtime
</code>
time zone file with a
version that uses rules differing from those in effect at
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
startup, restart
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
so that it uses the updated rules.
Otherwise,
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
might not notice when
the system changes its time.
</p>
</li>
<li class="listitem">
<p>
If you use named time zones with MySQL, make sure that the
time zone tables in the
<code class="literal">
mysql
</code>
database
are up to date:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
If your system has its own zoneinfo database, reload the
MySQL time zone tables whenever the zoneinfo database is
updated.
</p>
</li>
<li class="listitem">
<p>
For systems that do not have their own zoneinfo
database, check the MySQL Developer Zone for updates.
When a new update is available, download it and use it
to replace the content of your current time zone tables.
</p>
</li>
</ul>
</div>
<p>
For instructions for both methods, see
<a class="xref" href="time-zone-support.html#time-zone-installation" title="Populating the Time Zone Tables">
Populating the Time Zone Tables
</a>
.
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
caches time zone information that
it looks up, so after updating the time zone tables, restart
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
to make sure that it does not
continue to serve outdated time zone data.
</p>
</li>
</ul>
</div>
<p>
If you are uncertain whether named time zones are available, for
use either as the server's time zone setting or by clients that
set their own time zone, check whether your time zone tables are
empty. The following query determines whether the table that
contains time zone names has any rows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa12823191"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> mysql<span class="token punctuation">.</span>time_zone_name<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
A count of zero indicates that the table is empty. In this case,
no applications currently are using named time zones, and you
need not update the tables (unless you want to enable named time
zone support). A count greater than zero indicates that the
table is not empty and that its contents are available to be
used for named time zone support. In this case, be sure to
reload your time zone tables so that applications that use named
time zones can obtain correct query results.
</p>
<a class="indexterm" name="idm46045260317488">
</a>
<p>
To check whether your MySQL installation is updated properly for
a change in Daylight Saving Time rules, use a test like the one
following. The example uses values that are appropriate for the
2007 DST 1-hour change that occurs in the United States on March
11 at 2 a.m.
</p>
<p>
The test uses this query:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa89635680"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span>
<span class="token function">CONVERT_TZ</span><span class="token punctuation">(</span><span class="token string">'2007-03-11 2:00:00'</span><span class="token punctuation">,</span><span class="token string">'US/Eastern'</span><span class="token punctuation">,</span><span class="token string">'US/Central'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> time1<span class="token punctuation">,</span>
<span class="token function">CONVERT_TZ</span><span class="token punctuation">(</span><span class="token string">'2007-03-11 3:00:00'</span><span class="token punctuation">,</span><span class="token string">'US/Eastern'</span><span class="token punctuation">,</span><span class="token string">'US/Central'</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> time2<span class="token punctuation">;</span></code></pre>
</div>
<p>
The two time values indicate the times at which the DST change
occurs, and the use of named time zones requires that the time
zone tables be used. The desired result is that both queries
return the same result (the input time, converted to the
equivalent value in the 'US/Central' time zone).
</p>
<p>
Before updating the time zone tables, you see an incorrect
result like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96394446"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> time1 <span class="token punctuation">|</span> time2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2007<span class="token punctuation">-</span>03<span class="token punctuation">-</span>11 01:00:00 <span class="token punctuation">|</span> 2007<span class="token punctuation">-</span>03<span class="token punctuation">-</span>11 02:00:00 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
After updating the tables, you should see the correct result:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa73600921"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> time1 <span class="token punctuation">|</span> time2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2007<span class="token punctuation">-</span>03<span class="token punctuation">-</span>11 01:00:00 <span class="token punctuation">|</span> 2007<span class="token punctuation">-</span>03<span class="token punctuation">-</span>11 01:00:00 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="time-zone-leap-seconds">
</a>
Time Zone Leap Second Support
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045260308928">
</a>
<p>
Leap second values are returned with a time part that ends with
<code class="literal">
:59:59
</code>
. This means that a function such as
<a class="link" href="date-and-time-functions.html#function_now">
<code class="literal">
NOW()
</code>
</a>
can return the same value
for two or three consecutive seconds during the leap second. It
remains true that literal temporal values having a time part
that ends with
<code class="literal">
:59:60
</code>
or
<code class="literal">
:59:61
</code>
are considered invalid.
</p>
<p>
If it is necessary to search for
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
values one second
before the leap second, anomalous results may be obtained if you
use a comparison with
<code class="literal">
'
<em class="replaceable">
<code>
YYYY-MM-DD
hh:mm:ss
</code>
</em>
'
</code>
values. The following example
demonstrates this. It changes the session time zone to UTC so
there is no difference between internal
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
values (which are in
UTC) and displayed values (which have time zone correction
applied).
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa75477047"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>
a <span class="token datatype">INT</span><span class="token punctuation">,</span>
ts <span class="token datatype">TIMESTAMP</span> <span class="token keyword">DEFAULT</span> <span class="token keyword">CURRENT_TIMESTAMP</span><span class="token punctuation">,</span>
<span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>ts<span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.01 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- change to UTC</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> time_zone <span class="token operator">=</span> <span class="token string">'+00:00'</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- Simulate NOW() = '2008-12-31 23:59:59'</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token datatype">timestamp</span> <span class="token operator">=</span> <span class="token number">1230767999</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- Simulate NOW() = '2008-12-31 23:59:60'</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token datatype">timestamp</span> <span class="token operator">=</span> <span class="token number">1230768000</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- values differ internally but display the same</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> a<span class="token punctuation">,</span> ts<span class="token punctuation">,</span> <span class="token function">UNIX_TIMESTAMP</span><span class="token punctuation">(</span>ts<span class="token punctuation">)</span> <span class="token keyword">FROM</span> t1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> ts <span class="token punctuation">|</span> UNIX_TIMESTAMP(ts) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 2008<span class="token punctuation">-</span>12<span class="token punctuation">-</span>31 23:59:59 <span class="token punctuation">|</span> 1230767999 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 2008<span class="token punctuation">-</span>12<span class="token punctuation">-</span>31 23:59:59 <span class="token punctuation">|</span> 1230768000 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- only the non-leap value matches</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> ts <span class="token operator">=</span> <span class="token string">'2008-12-31 23:59:59'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> ts <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 2008<span class="token punctuation">-</span>12<span class="token punctuation">-</span>31 23:59:59 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- the leap value with seconds=60 is invalid</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> ts <span class="token operator">=</span> <span class="token string">'2008-12-31 23:59:60'</span><span class="token punctuation">;</span>
<span class="token keyword">Empty</span> <span class="token keyword">set</span><span class="token punctuation">,</span> <span class="token number">2</span> <span class="token keyword">warnings</span> <span class="token punctuation">(</span><span class="token number">0.00</span> sec<span class="token punctuation">)</span></code></pre>
</div>
<p>
To work around this, you can use a comparison based on the UTC
value actually stored in the column, which has the leap second
correction applied:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa5070168"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token comment" spellcheck="true">-- selecting using UNIX_TIMESTAMP value return leap value</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> <span class="token function">UNIX_TIMESTAMP</span><span class="token punctuation">(</span>ts<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token number">1230768000</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> ts <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 2008<span class="token punctuation">-</span>12<span class="token punctuation">-</span>31 23:59:59 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-miscellaneous-tables.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="performance-schema-miscellaneous-tables">
</a>
29.12.22 Performance Schema Miscellaneous Tables
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="performance-schema-component-scheduler-tasks-table.html">
29.12.22.1 The component_scheduler_tasks Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-error-log-table.html">
29.12.22.2 The error_log Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-host-cache-table.html">
29.12.22.3 The host_cache Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-innodb-redo-log-files-table.html">
29.12.22.4 The innodb_redo_log_files Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-log-status-table.html">
29.12.22.5 The log_status Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-performance-timers-table.html">
29.12.22.6 The performance_timers Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-processlist-table.html">
29.12.22.7 The processlist Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-threads-table.html">
29.12.22.8 The threads Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-tls-channel-status-table.html">
29.12.22.9 The tls_channel_status Table
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="performance-schema-user-defined-functions-table.html">
29.12.22.10 The user_defined_functions Table
</a>
</span>
</dt>
</dl>
</div>
<p>
The following sections describe tables that do not fall into the
table categories discussed in the preceding sections:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="performance-schema-component-scheduler-tasks-table.html" title="29.12.22.1 The component_scheduler_tasks Table">
<code class="literal">
component_scheduler_tasks
</code>
</a>
: The
current status of each scheduled task.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-error-log-table.html" title="29.12.22.2 The error_log Table">
<code class="literal">
error_log
</code>
</a>
: The most recent
events written to the error log.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-host-cache-table.html" title="29.12.22.3 The host_cache Table">
<code class="literal">
host_cache
</code>
</a>
: Information from
the internal host cache.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-innodb-redo-log-files-table.html" title="29.12.22.4 The innodb_redo_log_files Table">
<code class="literal">
innodb_redo_log_files
</code>
</a>
:
Information about InnoDB redo log files.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-log-status-table.html" title="29.12.22.5 The log_status Table">
<code class="literal">
log_status
</code>
</a>
: Information about
server logs for backup purposes.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-performance-timers-table.html" title="29.12.22.6 The performance_timers Table">
<code class="literal">
performance_timers
</code>
</a>
: Which event
timers are available.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-processlist-table.html" title="29.12.22.7 The processlist Table">
<code class="literal">
processlist
</code>
</a>
: Information about
server processes.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
: Information about
server threads.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-tls-channel-status-table.html" title="29.12.22.9 The tls_channel_status Table">
<code class="literal">
tls_channel_status
</code>
</a>
: TLS context
properties for connection interfaces.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="performance-schema-user-defined-functions-table.html" title="29.12.22.10 The user_defined_functions Table">
<code class="literal">
user_defined_functions
</code>
</a>
:
Loadable functions registered by a component, plugin, or
<a class="link" href="create-function-loadable.html" title="15.7.4.1 CREATE FUNCTION Statement for Loadable Functions">
<code class="literal">
CREATE
FUNCTION
</code>
</a>
statement.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/spatial-geojson-functions.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="spatial-geojson-functions">
</a>
14.16.11 Spatial GeoJSON Functions
</h3>
</div>
</div>
</div>
<p>
This section describes functions for converting between GeoJSON
documents and spatial values. GeoJSON is an open standard for
encoding geometric/geographical features. For more information,
see
<a class="ulink" href="http://geojson.org" target="_blank">
http://geojson.org
</a>
. The functions discussed
here follow GeoJSON specification revision 1.0.
</p>
<p>
GeoJSON supports the same geometric/geographic data types that
MySQL supports. Feature and FeatureCollection objects are not
supported, except that geometry objects are extracted from them.
CRS support is limited to values that identify an SRID.
</p>
<p>
MySQL also supports a native
<a class="link" href="json.html" title="13.5 The JSON Data Type">
<code class="literal">
JSON
</code>
</a>
data type and a set of SQL functions to enable operations on JSON
values. For more information, see
<a class="xref" href="json.html" title="13.5 The JSON Data Type">
Section 13.5, “The JSON Data Type”
</a>
, and
<a class="xref" href="json-functions.html" title="14.17 JSON Functions">
Section 14.17, “JSON Functions”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<a name="function_st-asgeojson">
</a>
<p>
<a class="link" href="spatial-geojson-functions.html#function_st-asgeojson">
<code class="literal">
ST_AsGeoJSON(
<em class="replaceable">
<code>
g
</code>
</em>
[,
<em class="replaceable">
<code>
max_dec_digits
</code>
</em>
[,
<em class="replaceable">
<code>
options
</code>
</em>
]])
</code>
</a>
</p>
<a class="indexterm" name="idm46045196155456">
</a>
<p>
Generates a GeoJSON object from the geometry
<em class="replaceable">
<code>
g
</code>
</em>
. The object string has the
connection character set and collation.
</p>
<p>
If any argument is
<code class="literal">
NULL
</code>
, the return value
is
<code class="literal">
NULL
</code>
. If any non-
<code class="literal">
NULL
</code>
argument is invalid, an error occurs.
</p>
<p>
<em class="replaceable">
<code>
max_dec_digits
</code>
</em>
, if specified,
limits the number of decimal digits for coordinates and causes
rounding of output. If not specified, this argument defaults
to its maximum value of 2
<sup>
32
</sup>
−
1. The minimum is 0.
</p>
<p>
<em class="replaceable">
<code>
options
</code>
</em>
, if specified, is a
bitmask. The following table shows the permitted flag values.
If the geometry argument has an SRID of 0, no CRS object is
produced even for those flag values that request one.
</p>
<div class="informaltable">
<table summary="Option flags for the ST_AsGeoJSON() function.">
<colgroup>
<col style="width: 10%"/>
<col style="width: 90%"/>
</colgroup>
<thead>
<tr>
<th>
Flag Value
</th>
<th>
Meaning
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
0
</td>
<td>
No options. This is the default if
<em class="replaceable">
<code>
options
</code>
</em>
is
not specified.
</td>
</tr>
<tr>
<td>
1
</td>
<td>
Add a bounding box to the output.
</td>
</tr>
<tr>
<td>
2
</td>
<td>
Add a short-format CRS URN to the output. The default format is a short
format
(
<code class="literal">
EPSG:
<em class="replaceable">
<code>
srid
</code>
</em>
</code>
).
</td>
</tr>
<tr>
<td>
4
</td>
<td>
Add a long-format CRS URN
(
<code class="literal">
urn:ogc:def:crs:EPSG::
<em class="replaceable">
<code>
srid
</code>
</em>
</code>
).
This flag overrides flag 2. For example, option values
of 5 and 7 mean the same (add a bounding box and a
long-format CRS URN).
</td>
</tr>
</tbody>
</table>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa68518300"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">ST_AsGeoJSON</span><span class="token punctuation">(</span><span class="token function">ST_GeomFromText</span><span class="token punctuation">(</span><span class="token string">'POINT(11.11111 12.22222)'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> ST_AsGeoJSON(ST_GeomFromText('POINT(11.11111 12.22222)'),2) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> {"type": "Point", "coordinates": [11.11, 12.22]} <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<a name="function_st-geomfromgeojson">
</a>
<p>
<a class="link" href="spatial-geojson-functions.html#function_st-geomfromgeojson">
<code class="literal">
ST_GeomFromGeoJSON(
<em class="replaceable">
<code>
str
</code>
</em>
[,
<em class="replaceable">
<code>
options
</code>
</em>
[,
<em class="replaceable">
<code>
srid
</code>
</em>
]])
</code>
</a>
</p>
<a class="indexterm" name="idm46045196122832">
</a>
<p>
Parses a string
<em class="replaceable">
<code>
str
</code>
</em>
representing a
GeoJSON object and returns a geometry.
</p>
<p>
If any argument is
<code class="literal">
NULL
</code>
, the return value
is
<code class="literal">
NULL
</code>
. If any non-
<code class="literal">
NULL
</code>
argument is invalid, an error occurs.
</p>
<p>
<em class="replaceable">
<code>
options
</code>
</em>
, if given, describes how to
handle GeoJSON documents that contain geometries with
coordinate dimensions higher than 2. The following table shows
the permitted
<em class="replaceable">
<code>
options
</code>
</em>
values.
</p>
<div class="informaltable">
<table summary="Option flags for the ST_GeomFromGeoJSON() function.">
<colgroup>
<col style="width: 10%"/>
<col style="width: 90%"/>
</colgroup>
<thead>
<tr>
<th>
Option Value
</th>
<th>
Meaning
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
1
</td>
<td>
Reject the document and produce an error. This is the default if
<em class="replaceable">
<code>
options
</code>
</em>
is not specified.
</td>
</tr>
<tr>
<td>
2, 3, 4
</td>
<td>
Accept the document and strip off the coordinates for higher coordinate
dimensions.
</td>
</tr>
</tbody>
</table>
</div>
<p>
<em class="replaceable">
<code>
options
</code>
</em>
values of 2, 3, and 4
currently produce the same effect. If geometries with
coordinate dimensions higher than 2 are supported in the
future, you can expect these values to produce different
effects.
</p>
<p>
The
<em class="replaceable">
<code>
srid
</code>
</em>
argument, if given, must
be a 32-bit unsigned integer. If not given, the geometry
return value has an SRID of 4326.
</p>
<p>
If
<em class="replaceable">
<code>
srid
</code>
</em>
refers to an undefined
spatial reference system (SRS), an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_srs_not_found" target="_top">
<code class="literal">
ER_SRS_NOT_FOUND
</code>
</a>
error occurs.
</p>
<p>
For geographic SRS geometry arguments, if any argument has a
longitude or latitude that is out of range, an error occurs:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
If a longitude value is not in the range (−180,
180], an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_longitude_out_of_range" target="_top">
<code class="literal">
ER_LONGITUDE_OUT_OF_RANGE
</code>
</a>
error occurs.
</p>
</li>
<li class="listitem">
<p>
If a latitude value is not in the range [−90, 90],
an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_latitude_out_of_range" target="_top">
<code class="literal">
ER_LATITUDE_OUT_OF_RANGE
</code>
</a>
error occurs.
</p>
</li>
</ul>
</div>
<p>
Ranges shown are in degrees. If an SRS uses another unit, the
range uses the corresponding values in its unit. The exact
range limits deviate slightly due to floating-point
arithmetic.
</p>
<p>
GeoJSON geometry, feature, and feature collection objects may
have a
<code class="literal">
crs
</code>
property. The parsing function
parses named CRS URNs in the
<code class="literal">
urn:ogc:def:crs:EPSG::
<em class="replaceable">
<code>
srid
</code>
</em>
</code>
and
<code class="literal">
EPSG:
<em class="replaceable">
<code>
srid
</code>
</em>
</code>
namespaces, but not CRSs given as link objects. Also,
<code class="literal">
urn:ogc:def:crs:OGC:1.3:CRS84
</code>
is recognized
as SRID 4326. If an object has a CRS that is not understood,
an error occurs, with the exception that if the optional
<em class="replaceable">
<code>
srid
</code>
</em>
argument is given, any CRS is
ignored even if it is invalid.
</p>
<p>
If a
<code class="literal">
crs
</code>
member that specifies an SRID
different from the top-level object SRID is found at a lower
level of the GeoJSON document, an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_invalid_geojson_crs_not_top_level" target="_top">
<code class="literal">
ER_INVALID_GEOJSON_CRS_NOT_TOP_LEVEL
</code>
</a>
error occurs.
</p>
<p>
As specified in the GeoJSON specification, parsing is
case-sensitive for the
<code class="literal">
type
</code>
member of the
GeoJSON input (
<code class="literal">
Point
</code>
,
<code class="literal">
LineString
</code>
, and so forth). The
specification is silent regarding case sensitivity for other
parsing, which in MySQL is not case-sensitive.
</p>
<p>
This example shows the parsing result for a simple GeoJSON
object. Observe that the order of coordinates depends on the
SRID used.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa62364940"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token variable">@json</span> <span class="token operator">=</span> <span class="token string">'{ "type": "Point", "coordinates": [102.0, 0.0]}'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">ST_AsText</span><span class="token punctuation">(</span><span class="token function">ST_GeomFromGeoJSON</span><span class="token punctuation">(</span><span class="token variable">@json</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> ST_AsText(ST_GeomFromGeoJSON(@json)) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> POINT(0 102) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">ST_SRID</span><span class="token punctuation">(</span><span class="token function">ST_GeomFromGeoJSON</span><span class="token punctuation">(</span><span class="token variable">@json</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> ST_SRID(ST_GeomFromGeoJSON(@json)) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 4326 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">ST_AsText</span><span class="token punctuation">(</span><span class="token function">ST_SRID</span><span class="token punctuation">(</span><span class="token function">ST_GeomFromGeoJSON</span><span class="token punctuation">(</span><span class="token variable">@json</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> ST_AsText(ST_SRID(ST_GeomFromGeoJSON(@json),0)) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> POINT(102 0) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/group-replication-consistency-guarantees.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="group-replication-consistency-guarantees">
</a>
20.5.3 Transaction Consistency Guarantees
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="group-replication-understanding-consistency-guarantees.html">
20.5.3.1 Understanding Transaction Consistency Guarantees
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="group-replication-configuring-consistency-guarantees.html">
20.5.3.2 Configuring Transaction Consistency Guarantees
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045133389872">
</a>
<p>
One of the major implications of a distributed system such as
Group Replication is the consistency guarantees that it provides
as a group. In other words, the consistency of the global
synchronization of transactions distributed across the members of
the group. This section describes how Group Replication handles
consistency guarantees depending on the events that occur in a
group, and how to best configure your group's consistency
guarantees.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-features-create-if-not-exists.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-features-create-if-not-exists">
</a>
19.5.1.6 Replication of CREATE ... IF NOT EXISTS Statements
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045135927520">
</a>
<a class="indexterm" name="idm46045135926016">
</a>
<p>
MySQL applies these rules when various
<code class="literal">
CREATE ... IF
NOT EXISTS
</code>
statements are replicated:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Every
<a class="link" href="create-database.html" title="15.1.12 CREATE DATABASE Statement">
<code class="literal">
CREATE
DATABASE IF NOT EXISTS
</code>
</a>
statement is replicated,
whether or not the database already exists on the source.
</p>
</li>
<li class="listitem">
<p>
Similarly, every
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
IF NOT EXISTS
</code>
</a>
statement without a
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
is replicated, whether
or not the table already exists on the source. This includes
<a class="link" href="create-table-like.html" title="15.1.20.3 CREATE TABLE ... LIKE Statement">
<code class="literal">
CREATE
TABLE IF NOT EXISTS ... LIKE
</code>
</a>
. Replication of
<a class="link" href="create-table-select.html" title="15.1.20.4 CREATE TABLE ... SELECT Statement">
<code class="literal">
CREATE
TABLE IF NOT EXISTS ... SELECT
</code>
</a>
follows somewhat
different rules; see
<a class="xref" href="replication-features-create-select.html" title="19.5.1.7 Replication of CREATE TABLE ... SELECT Statements">
Section 19.5.1.7, “Replication of CREATE TABLE ... SELECT Statements”
</a>
, for
more information.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="create-event.html" title="15.1.13 CREATE EVENT Statement">
<code class="literal">
CREATE EVENT
IF NOT EXISTS
</code>
</a>
is always replicated, whether or not
the event named in the statement already exists on the
source.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
is written to the
binary log only if successful. If the statement includes
<code class="literal">
IF NOT EXISTS
</code>
, it is considered
successful, and is logged as long as at least one user named
in the statement is created; in such cases, the statement is
logged as written; this includes references to existing
users that were not created. See
<a class="xref" href="create-user.html#create-user-binary-logging" title="CREATE USER Binary Logging">
CREATE USER Binary Logging
</a>
, for more
information.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="create-procedure.html" title="15.1.17 CREATE PROCEDURE and CREATE FUNCTION Statements">
<code class="literal">
CREATE
PROCEDURE IF NOT EXISTS
</code>
</a>
,
<a class="link" href="create-function.html" title="15.1.14 CREATE FUNCTION Statement">
<code class="literal">
CREATE
FUNCTION IF NOT EXISTS
</code>
</a>
, or
<a class="link" href="create-trigger.html" title="15.1.22 CREATE TRIGGER Statement">
<code class="literal">
CREATE
TRIGGER IF NOT EXISTS
</code>
</a>
, if successful, is written
in its entirety to the binary log (including the
<code class="literal">
IF
NOT EXISTS
</code>
clause), whether or not the statement
raised a warning because the object (procedure, function, or
trigger) already existed.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/group-replication-responses-failure-rejoin.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="group-replication-responses-failure-rejoin">
</a>
20.7.7.3 Auto-Rejoin
</h4>
</div>
</div>
</div>
<p>
The
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_autorejoin_tries">
<code class="literal">
group_replication_autorejoin_tries
</code>
</a>
system variable makes a member that has been expelled or reached
its unreachable majority timeout try to rejoin the group
automatically. The default (3), means that the member
automatically makes 3 attempts to rejoin the group, with 5
minutes between each attempt.
</p>
<p>
When auto-rejoin is not activated, a member accepts its
expulsion as soon as it resumes communication, and proceeds to
the action specified by the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_exit_state_action">
<code class="literal">
group_replication_exit_state_action
</code>
</a>
system variable. After this, manual intervention is needed to
bring the member back into the group. Using the auto-rejoin
feature is appropriate if you can tolerate the possibility of
stale reads and want to minimize the need for manual
intervention, especially where transient network issues fairly
often result in the expulsion of members.
</p>
<p>
With auto-rejoin, when the member's expulsion or unreachable
majority timeout is reached, it makes an attempt to rejoin
(using the current plugin option values), then continues to make
further auto-rejoin attempts up to the specified number of
tries. After an unsuccessful auto-rejoin attempt, the member
waits 5 minutes before the next try. The auto-rejoin attempts
and the time between them are called the auto-rejoin procedure.
If the specified number of tries is exhausted without the member
rejoining or being stopped, the member proceeds to the action
specified by the
<code class="literal">
group_replication_exit_state_action
</code>
system
variable.
</p>
<p>
During and between auto-rejoin attempts, a member remains in
super read only mode and displays an
<code class="literal">
ERROR
</code>
state on its view of the replication group. During this time,
the member does not accept writes. However, reads can still be
made on the member, with an increasing likelihood of stale reads
over time. If you do want to intervene to take the member
offline during the auto-rejoin procedure, the member can be
stopped manually at any time by using a
<a class="link" href="stop-group-replication.html" title="15.4.3.2 STOP GROUP_REPLICATION Statement">
<code class="literal">
STOP GROUP_REPLICATION
</code>
</a>
statement
or shutting down the server. If you cannot tolerate the
possibility of stale reads for any period of time, set the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_autorejoin_tries">
<code class="literal">
group_replication_autorejoin_tries
</code>
</a>
system variable to 0.
</p>
<p>
You can monitor the auto-rejoin procedure using the Performance
Schema. While an auto-rejoin procedure is taking place, the
Performance Schema table
<a class="link" href="performance-schema-events-stages-current-table.html" title="29.12.5.1 The events_stages_current Table">
<code class="literal">
events_stages_current
</code>
</a>
shows the
event
<span class="quote">
“
<span class="quote">
Undergoing auto-rejoin procedure
</span>
”
</span>
, with the
number of retries that have been attempted so far during this
instance of the procedure (in the
<code class="literal">
WORK_COMPLETED
</code>
column). The
<a class="link" href="performance-schema-stage-summary-tables.html" title="29.12.20.2 Stage Summary Tables">
<code class="literal">
events_stages_summary_global_by_event_name
</code>
</a>
table shows the number of times the server instance has
initiated the auto-rejoin procedure (in the
<code class="literal">
COUNT_STAR
</code>
column). The
<a class="link" href="performance-schema-events-stages-history-long-table.html" title="29.12.5.3 The events_stages_history_long Table">
<code class="literal">
events_stages_history_long
</code>
</a>
table
shows the time each of these auto-rejoin procedures was
completed (in the
<code class="literal">
TIMER_END
</code>
column). While a
member is rejoining a replication group, its status can be
displayed as
<code class="literal">
OFFLINE
</code>
or
<code class="literal">
ERROR
</code>
before the group completes the
compatibility checks and accepts it as a member. When the member
is catching up with the group's transactions, its status is
<code class="literal">
RECOVERING
</code>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/caching-sha2-pluggable-authentication.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="caching-sha2-pluggable-authentication">
</a>
8.4.1.2 Caching SHA-2 Pluggable Authentication
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045246295760">
</a>
<a class="indexterm" name="idm46045246294656">
</a>
<p>
MySQL provides two authentication plugins that implement SHA-256
hashing for user account passwords:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
caching_sha2_password
</code>
: Implements SHA-256
authentication (like
<code class="literal">
sha256_password
</code>
),
but uses caching on the server side for better performance
and has additional features for wider applicability.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
sha256_password
</code>
(deprecated): Implements
basic SHA-256 authentication. This is deprecated and subject
to removal, do not use this authentication plugin.
</p>
</li>
</ul>
</div>
<p>
This section describes the caching SHA-2 authentication plugin.
For information about the original basic (noncaching) deprecated
plugin, see
<a class="xref" href="sha256-pluggable-authentication.html" title="8.4.1.3 SHA-256 Pluggable Authentication">
Section 8.4.1.3, “SHA-256 Pluggable Authentication”
</a>
.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
In MySQL 8.4,
<code class="literal">
caching_sha2_password
</code>
is the default
authentication plugin rather than
<code class="literal">
mysql_native_password
</code>
(deprecated). For
information about the implications of this change for server
operation and compatibility of the server with clients and
connectors, see
<a class="ulink" href="/doc/refman/8.0/en/upgrading-from-previous-series.html#upgrade-caching-sha2-password" target="_top">
caching_sha2_password as the Preferred Authentication Plugin
</a>
.
</p>
</div>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
To connect to the server using an account that authenticates
with the
<code class="literal">
caching_sha2_password
</code>
plugin, you
must use either a secure connection or an unencrypted
connection that supports password exchange using an RSA key
pair, as described later in this section. Either way, the
<code class="literal">
caching_sha2_password
</code>
plugin uses
MySQL's encryption capabilities. See
<a class="xref" href="encrypted-connections.html" title="8.3 Using Encrypted Connections">
Section 8.3, “Using Encrypted Connections”
</a>
.
</p>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
In the name
<code class="literal">
sha256_password
</code>
,
<span class="quote">
“
<span class="quote">
sha256
</span>
”
</span>
refers to the 256-bit digest length the
plugin uses for encryption. In the name
<code class="literal">
caching_sha2_password
</code>
,
<span class="quote">
“
<span class="quote">
sha2
</span>
”
</span>
refers more generally to the SHA-2 class of encryption
algorithms, of which 256-bit encryption is one instance. The
latter name choice leaves room for future expansion of
possible digest lengths without changing the plugin name.
</p>
</div>
<p>
The
<code class="literal">
caching_sha2_password
</code>
plugin has these
advantages, compared to the deprecated
<code class="literal">
sha256_password
</code>
plugin:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
On the server side, an in-memory cache enables faster
reauthentication of users who have connected previously when
they connect again.
</p>
</li>
<li class="listitem">
<p>
RSA-based password exchange is available regardless of the
SSL library against which MySQL is linked.
</p>
</li>
<li class="listitem">
<p>
Support is provided for client connections that use the Unix
socket-file and shared-memory protocols.
</p>
</li>
</ul>
</div>
<p>
The following table shows the plugin names on the server and
client sides.
</p>
<div class="table">
<a name="idm46045246271328">
</a>
<p class="title">
<b>
Table 8.15 Plugin and Library Names for SHA-2 Authentication
</b>
</p>
<div class="table-contents">
<table summary="Names for the plugins and library file used for SHA-2 password authentication.">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<thead>
<tr>
<th>
Plugin or File
</th>
<th>
Plugin or File Name
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
Server-side plugin
</td>
<td>
<code class="literal">
caching_sha2_password
</code>
</td>
</tr>
<tr>
<td>
Client-side plugin
</td>
<td>
<code class="literal">
caching_sha2_password
</code>
</td>
</tr>
<tr>
<td>
Library file
</td>
<td>
None (plugins are built in)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
The following sections provide installation and usage
information specific to caching SHA-2 pluggable authentication:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="caching-sha2-pluggable-authentication.html#caching-sha2-pluggable-authentication-installation" title="Installing SHA-2 Pluggable Authentication">
Installing SHA-2 Pluggable Authentication
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="caching-sha2-pluggable-authentication.html#caching-sha2-pluggable-authentication-usage" title="Using SHA-2 Pluggable Authentication">
Using SHA-2 Pluggable Authentication
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="caching-sha2-pluggable-authentication.html#caching-sha2-pluggable-authentication-cache-operation" title="Cache Operation for SHA-2 Pluggable Authentication">
Cache Operation for SHA-2 Pluggable Authentication
</a>
</p>
</li>
</ul>
</div>
<p>
For general information about pluggable authentication in MySQL,
see
<a class="xref" href="pluggable-authentication.html" title="8.2.17 Pluggable Authentication">
Section 8.2.17, “Pluggable Authentication”
</a>
.
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="caching-sha2-pluggable-authentication-installation">
</a>
Installing SHA-2 Pluggable Authentication
</h5>
</div>
</div>
</div>
<p>
The
<code class="literal">
caching_sha2_password
</code>
plugin exists in
server and client forms:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The server-side plugin is built into the server, need not
be loaded explicitly, and cannot be disabled by unloading
it.
</p>
</li>
<li class="listitem">
<p>
The client-side plugin is built into the
<code class="literal">
libmysqlclient
</code>
client library and is
available to any program linked against
<code class="literal">
libmysqlclient
</code>
.
</p>
</li>
</ul>
</div>
<p>
The server-side plugin uses the
<code class="literal">
sha2_cache_cleaner
</code>
audit plugin as a helper
to perform password cache management.
<code class="literal">
sha2_cache_cleaner
</code>
, like
<code class="literal">
caching_sha2_password
</code>
, is built in and need
not be installed.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="caching-sha2-pluggable-authentication-usage">
</a>
Using SHA-2 Pluggable Authentication
</h5>
</div>
</div>
</div>
<p>
To set up an account that uses the
<code class="literal">
caching_sha2_password
</code>
plugin for SHA-256
password hashing, use the following statement, where
<em class="replaceable">
<code>
password
</code>
</em>
is the desired account
password:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa97106768"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'sha2user'</span>@<span class="token string">'localhost'</span>
<span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> caching_sha2_password <span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">password</em>'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The server assigns the
<code class="literal">
caching_sha2_password
</code>
plugin to the account
and uses it to encrypt the password using SHA-256, storing
those values in the
<code class="literal">
plugin
</code>
and
<code class="literal">
authentication_string
</code>
columns of the
<code class="literal">
mysql.user
</code>
system table.
</p>
<p>
The preceding instructions do not assume that
<code class="literal">
caching_sha2_password
</code>
is the default
authentication plugin. If
<code class="literal">
caching_sha2_password
</code>
is the default
authentication plugin, a simpler
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE
USER
</code>
</a>
syntax can be used:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa92350584"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'sha2user'</span>@<span class="token string">'localhost'</span> <span class="token keyword">IDENTIFIED</span> <span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">password</em>'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The default plugin is determined by the value of the
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system
variable; the default is to use
<code class="literal">
caching_sha2_password
</code>
.
</p>
<p>
To use a different plugin, you must specify it using
<code class="literal">
IDENTIFIED WITH
</code>
. For example, to specify
the deprecated
<code class="literal">
mysql_native_password
</code>
plugin, use this statement:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa52499528"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'nativeuser'</span>@<span class="token string">'localhost'</span>
<span class="token keyword">IDENTIFIED</span> <span class="token keyword">WITH</span> mysql_native_password <span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">password</em>'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
<code class="literal">
caching_sha2_password
</code>
supports connections
over secure transport. If you follow the RSA configuration
procedure given later in this section, it also supports
encrypted password exchange using RSA over unencrypted
connections. RSA support has these characteristics:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
On the server side, two system variables name the RSA
private and public key-pair files:
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_private_key_path">
<code class="literal">
caching_sha2_password_private_key_path
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_public_key_path">
<code class="literal">
caching_sha2_password_public_key_path
</code>
</a>
.
The database administrator must set these variables at
server startup if the key files to use have names that
differ from the system variable default values.
</p>
</li>
<li class="listitem">
<p>
The server uses the
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_auto_generate_rsa_keys">
<code class="literal">
caching_sha2_password_auto_generate_rsa_keys
</code>
</a>
system variable to determine whether to automatically
generate the RSA key-pair files. See
<a class="xref" href="creating-ssl-rsa-files.html" title="8.3.3 Creating SSL and RSA Certificates and Keys">
Section 8.3.3, “Creating SSL and RSA Certificates and Keys”
</a>
.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="server-status-variables.html#statvar_Caching_sha2_password_rsa_public_key">
<code class="literal">
Caching_sha2_password_rsa_public_key
</code>
</a>
status variable displays the RSA public key value used by
the
<code class="literal">
caching_sha2_password
</code>
authentication plugin.
</p>
</li>
<li class="listitem">
<p>
Clients that are in possession of the RSA public key can
perform RSA key pair-based password exchange with the
server during the connection process, as described later.
</p>
</li>
<li class="listitem">
<p>
For connections by accounts that authenticate with
<code class="literal">
caching_sha2_password
</code>
and RSA key
pair-based password exchange, the server does not send the
RSA public key to clients by default. Clients can use a
client-side copy of the required public key, or request
the public key from the server.
</p>
<p>
Use of a trusted local copy of the public key enables the
client to avoid a round trip in the client/server
protocol, and is more secure than requesting the public
key from the server. On the other hand, requesting the
public key from the server is more convenient (it requires
no management of a client-side file) and may be acceptable
in secure network environments.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
For command-line clients, use the
<a class="link" href="mysql-command-options.html#option_mysql_server-public-key-path">
<code class="option">
--server-public-key-path
</code>
</a>
option to specify the RSA public key file. Use the
<a class="link" href="mysql-command-options.html#option_mysql_get-server-public-key">
<code class="option">
--get-server-public-key
</code>
</a>
option to request the public key from the server. The
following programs support the two options:
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
,
<span class="command">
<strong>
mysqlsh
</strong>
</span>
,
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin
</strong>
</span>
</a>
,
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
,
<a class="link" href="mysqlcheck.html" title="6.5.3 mysqlcheck — A Table Maintenance Program">
<span class="command">
<strong>
mysqlcheck
</strong>
</span>
</a>
,
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
,
<a class="link" href="mysqlimport.html" title="6.5.5 mysqlimport — A Data Import Program">
<span class="command">
<strong>
mysqlimport
</strong>
</span>
</a>
,
<a class="link" href="mysqlshow.html" title="6.5.6 mysqlshow — Display Database, Table, and Column Information">
<span class="command">
<strong>
mysqlshow
</strong>
</span>
</a>
,
<a class="link" href="mysqlslap.html" title="6.5.7 mysqlslap — A Load Emulation Client">
<span class="command">
<strong>
mysqlslap
</strong>
</span>
</a>
,
<span class="command">
<strong>
mysqltest
</strong>
</span>
.
</p>
</li>
<li class="listitem">
<p>
For programs that use the C API, call
<a class="ulink" href="/doc/c-api/8.4/en/mysql-options.html" target="_top">
<code class="literal">
mysql_options()
</code>
</a>
to
specify the RSA public key file by passing the
<code class="literal">
MYSQL_SERVER_PUBLIC_KEY
</code>
option and
the name of the file, or request the public key from
the server by passing the
<code class="literal">
MYSQL_OPT_GET_SERVER_PUBLIC_KEY
</code>
option.
</p>
</li>
<li class="listitem">
<p>
For replicas, use the
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE
REPLICATION SOURCE TO
</code>
</a>
statement with the
<code class="literal">
SOURCE_PUBLIC_KEY_PATH
</code>
option to
specify the RSA public key file, or the
<code class="literal">
GET_SOURCE_PUBLIC_KEY
</code>
option to
request the public key from the source. For Group
Replication, the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_recovery_public_key_path">
<code class="literal">
group_replication_recovery_public_key_path
</code>
</a>
and
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_recovery_get_public_key">
<code class="literal">
group_replication_recovery_get_public_key
</code>
</a>
system variables serve the same purpose.
</p>
</li>
</ul>
</div>
<p>
In all cases, if the option is given to specify a valid
public key file, it takes precedence over the option to
request the public key from the server.
</p>
</li>
</ul>
</div>
<p>
For clients that use the
<code class="literal">
caching_sha2_password
</code>
plugin, passwords are
never exposed as cleartext when connecting to the server. How
password transmission occurs depends on whether a secure
connection or RSA encryption is used:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If the connection is secure, an RSA key pair is
unnecessary and is not used. This applies to TCP
connections encrypted using TLS, as well as Unix
socket-file and shared-memory connections. The password is
sent as cleartext but cannot be snooped because the
connection is secure.
</p>
</li>
<li class="listitem">
<p>
If the connection is not secure, an RSA key pair is used.
This applies to TCP connections not encrypted using TLS
and named-pipe connections. RSA is used only for password
exchange between client and server, to prevent password
snooping. When the server receives the encrypted password,
it decrypts it. A scramble is used in the encryption to
prevent repeat attacks.
</p>
</li>
</ul>
</div>
<p>
To enable use of an RSA key pair for password exchange during
the client connection process, use the following procedure:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Create the RSA private and public key-pair files using the
instructions in
<a class="xref" href="creating-ssl-rsa-files.html" title="8.3.3 Creating SSL and RSA Certificates and Keys">
Section 8.3.3, “Creating SSL and RSA Certificates and Keys”
</a>
.
</p>
</li>
<li class="listitem">
<p>
If the private and public key files are located in the
data directory and are named
<code class="filename">
private_key.pem
</code>
and
<code class="filename">
public_key.pem
</code>
(the default values of
the
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_private_key_path">
<code class="literal">
caching_sha2_password_private_key_path
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_public_key_path">
<code class="literal">
caching_sha2_password_public_key_path
</code>
</a>
system variables), the server uses them automatically at
startup.
</p>
<p>
Otherwise, to name the key files explicitly, set the
system variables to the key file names in the server
option file. If the files are located in the server data
directory, you need not specify their full path names:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa34410336"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">caching_sha2_password_private_key_path</span><span class="token attr-value"><span class="token punctuation">=</span>myprivkey.pem</span>
<span class="token constant">caching_sha2_password_public_key_path</span><span class="token attr-value"><span class="token punctuation">=</span>mypubkey.pem</span></code></pre>
</div>
<p>
If the key files are not located in the data directory, or
to make their locations explicit in the system variable
values, use full path names:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa1238810"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">caching_sha2_password_private_key_path</span><span class="token attr-value"><span class="token punctuation">=</span>/usr/local/mysql/myprivkey.pem</span>
<span class="token constant">caching_sha2_password_public_key_path</span><span class="token attr-value"><span class="token punctuation">=</span>/usr/local/mysql/mypubkey.pem</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
If you want to change the number of hash rounds used by
<code class="literal">
caching_sha2_password
</code>
during password
generation, set the
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_digest_rounds">
<code class="literal">
caching_sha2_password_digest_rounds
</code>
</a>
system variable. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa4681520"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">caching_sha2_password_digest_rounds</span><span class="token attr-value"><span class="token punctuation">=</span>10000</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Restart the server, then connect to it and check the
<a class="link" href="server-status-variables.html#statvar_Caching_sha2_password_rsa_public_key">
<code class="literal">
Caching_sha2_password_rsa_public_key
</code>
</a>
status variable value. The value actually displayed
differs from that shown here, but should be nonempty:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa14112582"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">STATUS</span> <span class="token operator">LIKE</span> <span class="token string">'Caching_sha2_password_rsa_public_key'</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Variable_name<span class="token punctuation">:</span> Caching_sha2_password_rsa_public_key
Value<span class="token punctuation">:</span> -----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDO9nRUDd+KvSZgY7cNBZMNpwX6
MvE1PbJFXO7u18nJ9lwc99Du/E7lw6CVXw7VKrXPeHbVQUzGyUNkf45Nz/ckaaJa
aLgJOBCIDmNVnyU54OT/1lcs2xiyfaDMe8fCJ64ZwTnKbY2gkt1IMjUAB5Ogd5kJ
g8aV7EtKwyhHb0c30QIDAQAB
-----END PUBLIC KEY-----</span></code></pre>
</div>
<p>
If the value is empty, the server found some problem with
the key files. Check the error log for diagnostic
information.
</p>
</li>
</ol>
</div>
<p>
After the server has been configured with the RSA key files,
accounts that authenticate with the
<code class="literal">
caching_sha2_password
</code>
plugin have the
option of using those key files to connect to the server. As
mentioned previously, such accounts can use either a secure
connection (in which case RSA is not used) or an unencrypted
connection that performs password exchange using RSA. Suppose
that an unencrypted connection is used. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa50423237"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysql</span> <span class="token constant">--ssl-mode</span><span class="token attr-value"><span class="token punctuation">=</span>DISABLED</span> <span class="token property">-u</span> sha2user <span class="token property">-p</span>
Enter password<span class="token punctuation">:</span> <em class="replaceable">password</em></code></pre>
</div>
<p>
For this connection attempt by
<code class="literal">
sha2user
</code>
,
the server determines that
<code class="literal">
caching_sha2_password
</code>
is the appropriate
authentication plugin and invokes it (because that was the
plugin specified at
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
time). The plugin finds that the connection is not encrypted
and thus requires the password to be transmitted using RSA
encryption. However, the server does not send the public key
to the client, and the client provided no public key, so it
cannot encrypt the password and the connection fails:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-simple"><div class="docs-select-all right" id="sa88229052"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple">ERROR 2061 <span class="token punctuation">(</span>HY000<span class="token punctuation">)</span><span class="token operator">:</span> Authentication plugin 'caching_sha2_password'
reported error<span class="token operator">:</span> Authentication requires secure connection<span class="token punctuation">.</span></code></pre>
</div>
<p>
To request the RSA public key from the server, specify the
<a class="link" href="mysql-command-options.html#option_mysql_get-server-public-key">
<code class="option">
--get-server-public-key
</code>
</a>
option:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa72844158"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysql</span> <span class="token constant">--ssl-mode</span><span class="token attr-value"><span class="token punctuation">=</span>DISABLED</span> <span class="token property">-u</span> sha2user <span class="token property">-p</span> <span class="token property">--get-server-public-key</span>
Enter password<span class="token punctuation">:</span> <em class="replaceable">password</em></code></pre>
</div>
<p>
In this case, the server sends the RSA public key to the
client, which uses it to encrypt the password and returns the
result to the server. The plugin uses the RSA private key on
the server side to decrypt the password and accepts or rejects
the connection based on whether the password is correct.
</p>
<p>
Alternatively, if the client has a file containing a local
copy of the RSA public key required by the server, it can
specify the file using the
<a class="link" href="mysql-command-options.html#option_mysql_server-public-key-path">
<code class="option">
--server-public-key-path
</code>
</a>
option:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa79796620"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysql</span> <span class="token constant">--ssl-mode</span><span class="token attr-value"><span class="token punctuation">=</span>DISABLED</span> <span class="token property">-u</span> sha2user <span class="token property">-p</span> <span class="token constant">--server-public-key-path</span><span class="token attr-value"><span class="token punctuation">=</span><em class="replaceable">file_name</em></span>
Enter password<span class="token punctuation">:</span> <em class="replaceable">password</em></code></pre>
</div>
<p>
In this case, the client uses the public key to encrypt the
password and returns the result to the server. The plugin uses
the RSA private key on the server side to decrypt the password
and accepts or rejects the connection based on whether the
password is correct.
</p>
<p>
The public key value in the file named by the
<a class="link" href="mysql-command-options.html#option_mysql_server-public-key-path">
<code class="option">
--server-public-key-path
</code>
</a>
option
should be the same as the key value in the server-side file
named by the
<a class="link" href="server-system-variables.html#sysvar_caching_sha2_password_public_key_path">
<code class="literal">
caching_sha2_password_public_key_path
</code>
</a>
system variable. If the key file contains a valid public key
value but the value is incorrect, an access-denied error
occurs. If the key file does not contain a valid public key,
the client program cannot use it.
</p>
<p>
Client users can obtain the RSA public key two ways:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The database administrator can provide a copy of the
public key file.
</p>
</li>
<li class="listitem">
<p>
A client user who can connect to the server some other way
can use a
<code class="literal">
SHOW STATUS LIKE
'Caching_sha2_password_rsa_public_key'
</code>
statement
and save the returned key value in a file.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="caching-sha2-pluggable-authentication-cache-operation">
</a>
Cache Operation for SHA-2 Pluggable Authentication
</h5>
</div>
</div>
</div>
<a class="indexterm" name="idm46045246135040">
</a>
<a class="indexterm" name="idm46045246133952">
</a>
<p>
On the server side, the
<code class="literal">
caching_sha2_password
</code>
plugin uses an
in-memory cache for faster authentication of clients who have
connected previously. Entries consist of
account-name/password-hash pairs. The cache works like this:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
When a client connects,
<code class="literal">
caching_sha2_password
</code>
checks whether
the client and password match some cache entry. If so,
authentication succeeds.
</p>
</li>
<li class="listitem">
<p>
If there is no matching cache entry, the plugin attempts
to verify the client against the credentials in the
<code class="literal">
mysql.user
</code>
system table. If this
succeeds,
<code class="literal">
caching_sha2_password
</code>
adds an
entry for the client to the hash. Otherwise,
authentication fails and the connection is rejected.
</p>
</li>
</ol>
</div>
<p>
In this way, when a client first connects, authentication
against the
<code class="literal">
mysql.user
</code>
system table occurs.
When the client connects subsequently, faster authentication
against the cache occurs.
</p>
<p>
Password cache operations other than adding entries are
handled by the
<code class="literal">
sha2_cache_cleaner
</code>
audit
plugin, which performs these actions on behalf of
<code class="literal">
caching_sha2_password
</code>
:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
It clears the cache entry for any account that is renamed
or dropped, or any account for which the credentials or
authentication plugin are changed.
</p>
</li>
<li class="listitem">
<p>
It empties the cache when the
<a class="link" href="flush.html#flush-privileges">
<code class="literal">
FLUSH
PRIVILEGES
</code>
</a>
statement is executed.
</p>
</li>
<li class="listitem">
<p>
It empties the cache at server shutdown. (This means the
cache is not persistent across server restarts.)
</p>
</li>
</ul>
</div>
<p>
Cache clearing operations affect the authentication
requirements for subsequent client connections. For each user
account, the first client connection for the user after any of
the following operations must use a secure connection (made
using TCP using TLS credentials, a Unix socket file, or shared
memory) or RSA key pair-based password exchange:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
After account creation.
</p>
</li>
<li class="listitem">
<p>
After a password change for the account.
</p>
</li>
<li class="listitem">
<p>
After
<a class="link" href="rename-user.html" title="15.7.1.7 RENAME USER Statement">
<code class="literal">
RENAME USER
</code>
</a>
for the
account.
</p>
</li>
<li class="listitem">
<p>
After
<a class="link" href="flush.html#flush-privileges">
<code class="literal">
FLUSH PRIVILEGES
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
<a class="link" href="flush.html#flush-privileges">
<code class="literal">
FLUSH PRIVILEGES
</code>
</a>
clears the
entire cache and affects all accounts that use the
<code class="literal">
caching_sha2_password
</code>
plugin. The other
operations clear specific cache entries and affect only
accounts that are part of the operation.
</p>
<p>
Once the user authenticates successfully, the account is
entered into the cache and subsequent connections do not
require a secure connection or the RSA key pair, until another
cache clearing event occurs that affects the account. (When
the cache can be used, the server uses a challenge-response
mechanism that does not use cleartext password transmission
and does not require a secure connection.)
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-compared.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-compared">
</a>
25.2.6 MySQL Server Using InnoDB Compared with NDB Cluster
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="mysql-cluster-ndb-innodb-engines.html">
25.2.6.1 Differences Between the NDB and InnoDB Storage Engines
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="mysql-cluster-ndb-innodb-workloads.html">
25.2.6.2 NDB and InnoDB Workloads
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="mysql-cluster-ndb-innodb-usage.html">
25.2.6.3 NDB and InnoDB Feature Usage Summary
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045123918208">
</a>
<a class="indexterm" name="idm46045123916784">
</a>
<a class="indexterm" name="idm46045123915296">
</a>
<p>
MySQL Server offers a number of choices in storage engines. Since
both
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
and
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
can serve as transactional
MySQL storage engines, users of MySQL Server sometimes become
interested in NDB Cluster. They see
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
as a possible alternative or
upgrade to the default
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
storage
engine in MySQL. While
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
and
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
share common characteristics,
there are differences in architecture and implementation, so that
some existing MySQL Server applications and usage scenarios can be
a good fit for NDB Cluster, but not all of them.
</p>
<p>
In this section, we discuss and compare some characteristics of
the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
storage engine used by NDB
8.4 with
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
used in
MySQL 8.4. The next few sections provide a technical
comparison. In many instances, decisions about when and where to
use NDB Cluster must be made on a case-by-case basis, taking all
factors into consideration. While it is beyond the scope of this
documentation to provide specifics for every conceivable usage
scenario, we also attempt to offer some very general guidance on
the relative suitability of some common types of applications for
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
as opposed to
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
back ends.
</p>
<a class="indexterm" name="idm46045123898864">
</a>
<a class="indexterm" name="idm46045123897376">
</a>
<a class="indexterm" name="idm46045123895888">
</a>
<p>
NDB Cluster 8.4 uses a
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
based on MySQL
8.4, including support for
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
1.1. While it is possible to use
<code class="literal">
InnoDB
</code>
tables
with NDB Cluster, such tables are not clustered. It is also not
possible to use programs or libraries from an NDB Cluster 8.4
distribution with MySQL Server 8.4, or the reverse.
</p>
<p>
While it is also true that some types of common business
applications can be run either on NDB Cluster or on MySQL Server
(most likely using the
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
storage
engine), there are some important architectural and implementation
differences.
<a class="xref" href="mysql-cluster-ndb-innodb-engines.html" title="25.2.6.1 Differences Between the NDB and InnoDB Storage Engines">
Section 25.2.6.1, “Differences Between the NDB and InnoDB Storage Engines”
</a>
,
provides a summary of the these differences. Due to the
differences, some usage scenarios are clearly more suitable for
one engine or the other; see
<a class="xref" href="mysql-cluster-ndb-innodb-workloads.html" title="25.2.6.2 NDB and InnoDB Workloads">
Section 25.2.6.2, “NDB and InnoDB Workloads”
</a>
. This in turn
has an impact on the types of applications that better suited for
use with
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
or
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
. See
<a class="xref" href="mysql-cluster-ndb-innodb-usage.html" title="25.2.6.3 NDB and InnoDB Feature Usage Summary">
Section 25.2.6.3, “NDB and InnoDB Feature Usage Summary”
</a>
, for a comparison
of the relative suitability of each for use in common types of
database applications.
</p>
<p>
For information about the relative characteristics of the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
and
<a class="link" href="memory-storage-engine.html" title="18.3 The MEMORY Storage Engine">
<code class="literal">
MEMORY
</code>
</a>
storage engines, see
<a class="xref" href="memory-storage-engine.html#memory-storage-engine-compared-cluster" title="When to Use MEMORY or NDB Cluster">
When to Use MEMORY or NDB Cluster
</a>
.
</p>
<p>
See
<a class="xref" href="storage-engines.html" title="Chapter 18 Alternative Storage Engines">
Chapter 18,
<i>
Alternative Storage Engines
</i>
</a>
, for additional information
about MySQL storage engines.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/drop-resource-group.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="drop-resource-group">
</a>
15.7.2.3 DROP RESOURCE GROUP Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045172765920">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa49152348"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">RESOURCE</span> <span class="token keyword">GROUP</span> <em class="replaceable">group_name</em> <span class="token punctuation">[</span><span class="token keyword">FORCE</span><span class="token punctuation">]</span></code></pre>
</div>
<p>
<a class="link" href="drop-resource-group.html" title="15.7.2.3 DROP RESOURCE GROUP Statement">
<code class="literal">
DROP RESOURCE GROUP
</code>
</a>
is used for
resource group management (see
<a class="xref" href="resource-groups.html" title="7.1.16 Resource Groups">
Section 7.1.16, “Resource Groups”
</a>
). This statement drops a
resource group. It requires the
<a class="link" href="privileges-provided.html#priv_resource-group-admin">
<code class="literal">
RESOURCE_GROUP_ADMIN
</code>
</a>
privilege.
</p>
<p>
<em class="replaceable">
<code>
group_name
</code>
</em>
identifies which resource
group to drop. If the group does not exist, an error occurs.
</p>
<p>
The
<code class="literal">
FORCE
</code>
modifier determines statement
behavior if the resource group has any threads assigned to it:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If
<code class="literal">
FORCE
</code>
is not given and any threads are
assigned to the group, an error occurs.
</p>
</li>
<li class="listitem">
<p>
If
<code class="literal">
FORCE
</code>
is given, existing threads in
the group are moved to their respective default group
(system threads to
<code class="literal">
SYS_default
</code>
, user
threads to
<code class="literal">
USR_default
</code>
).
</p>
</li>
</ul>
</div>
<p>
Examples:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Drop a group, failing if the group contains any threads:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa16796535"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">RESOURCE</span> <span class="token keyword">GROUP</span> rg1<span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Drop a group and move existing threads to the default
groups:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa8926896"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">RESOURCE</span> <span class="token keyword">GROUP</span> rg2 <span class="token keyword">FORCE</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
Resource group management is local to the server on which it
occurs.
<a class="link" href="drop-resource-group.html" title="15.7.2.3 DROP RESOURCE GROUP Statement">
<code class="literal">
DROP RESOURCE GROUP
</code>
</a>
statements are not written to the binary log and are not
replicated.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/show-create-procedure.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="show-create-procedure">
</a>
15.7.7.10 SHOW CREATE PROCEDURE Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045170908752">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa93478601"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">PROCEDURE</span> <em class="replaceable">proc_name</em></code></pre>
</div>
<p>
This statement is a MySQL extension. It returns the exact string
that can be used to re-create the named stored procedure. A
similar statement,
<a class="link" href="show-create-function.html" title="15.7.7.9 SHOW CREATE FUNCTION Statement">
<code class="literal">
SHOW CREATE
FUNCTION
</code>
</a>
, displays information about stored functions
(see
<a class="xref" href="show-create-function.html" title="15.7.7.9 SHOW CREATE FUNCTION Statement">
Section 15.7.7.9, “SHOW CREATE FUNCTION Statement”
</a>
).
</p>
<p>
To use either statement, you must be the user named as the
routine
<code class="literal">
DEFINER
</code>
, have the
<a class="link" href="privileges-provided.html#priv_show-routine">
<code class="literal">
SHOW_ROUTINE
</code>
</a>
privilege, have the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege at the global
level, or have the
<a class="link" href="privileges-provided.html#priv_create-routine">
<code class="literal">
CREATE
ROUTINE
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_alter-routine">
<code class="literal">
ALTER ROUTINE
</code>
</a>
,
or
<a class="link" href="privileges-provided.html#priv_execute">
<code class="literal">
EXECUTE
</code>
</a>
privilege granted at a
scope that includes the routine. The value displayed for the
<code class="literal">
Create Procedure
</code>
or
<code class="literal">
Create
Function
</code>
field is
<code class="literal">
NULL
</code>
if you have
only
<a class="link" href="privileges-provided.html#priv_create-routine">
<code class="literal">
CREATE ROUTINE
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_alter-routine">
<code class="literal">
ALTER ROUTINE
</code>
</a>
, or
<a class="link" href="privileges-provided.html#priv_execute">
<code class="literal">
EXECUTE
</code>
</a>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa9381883"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">PROCEDURE</span> test<span class="token punctuation">.</span>citycount\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Procedure<span class="token punctuation">:</span> citycount
sql_mode<span class="token punctuation">:</span> ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,
NO_ZERO_IN_DATE,NO_ZERO_DATE,
ERROR_FOR_DIVISION_BY_ZERO,
NO_ENGINE_SUBSTITUTION
Create Procedure<span class="token punctuation">:</span> CREATE DEFINER=`me`@`localhost`
PROCEDURE `citycount`(IN country CHAR(3), OUT cities INT)
BEGIN
SELECT COUNT(<span class="token punctuation">*</span>) INTO cities FROM world.city
WHERE CountryCode = country;
END
character_set_client<span class="token punctuation">:</span> utf8mb4
collation_connection<span class="token punctuation">:</span> utf8mb4_0900_ai_ci
Database Collation<span class="token punctuation">:</span> utf8mb4_0900_ai_ci
</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">FUNCTION</span> test<span class="token punctuation">.</span>hello\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Function<span class="token punctuation">:</span> hello
sql_mode<span class="token punctuation">:</span> ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,
NO_ZERO_IN_DATE,NO_ZERO_DATE,
ERROR_FOR_DIVISION_BY_ZERO,
NO_ENGINE_SUBSTITUTION
Create Function<span class="token punctuation">:</span> CREATE DEFINER=`me`@`localhost`
FUNCTION `hello`(s CHAR(20))
RETURNS char(50) CHARSET utf8mb4
DETERMINISTIC
RETURN CONCAT('Hello, ',s,'!')
character_set_client<span class="token punctuation">:</span> utf8mb4
collation_connection<span class="token punctuation">:</span> utf8mb4_0900_ai_ci
Database Collation<span class="token punctuation">:</span> utf8mb4_0900_ai_ci</span></code></pre>
</div>
<p>
<code class="literal">
character_set_client
</code>
is the session value of
the
<a class="link" href="server-system-variables.html#sysvar_character_set_client">
<code class="literal">
character_set_client
</code>
</a>
system
variable when the routine was created.
<code class="literal">
collation_connection
</code>
is the session value of
the
<a class="link" href="server-system-variables.html#sysvar_collation_connection">
<code class="literal">
collation_connection
</code>
</a>
system
variable when the routine was created.
<code class="literal">
Database
Collation
</code>
is the collation of the database with which
the routine is associated.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-problems.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="replication-problems">
</a>
19.5.4 Troubleshooting Replication
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045134696768">
</a>
<p>
If you have followed the instructions but your replication setup
is not working, the first thing to do is
<span class="emphasis">
<em>
check the error
log for messages
</em>
</span>
. Many users have lost time by not
doing this soon enough after encountering problems.
</p>
<p>
If you cannot tell from the error log what the problem was, try
the following techniques:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Verify that the source has binary logging enabled by issuing a
<a class="link" href="show-binary-log-status.html" title="15.7.7.1 SHOW BINARY LOG STATUS Statement">
<code class="literal">
SHOW BINARY LOG STATUS
</code>
</a>
statement. Binary logging is enabled by default. If binary
logging is enabled,
<code class="literal">
Position
</code>
is nonzero. If
binary logging is not enabled, verify that you are not running
the source with any settings that disable binary logging, such
as the
<a class="link" href="replication-options-binary-log.html#option_mysqld_log-bin">
<code class="option">
--skip-log-bin
</code>
</a>
option.
</p>
</li>
<li class="listitem">
<p>
Verify that the
<a class="link" href="replication-options.html#sysvar_server_id">
<code class="literal">
server_id
</code>
</a>
system variable was set at startup on both the source and
replica and that the ID value is unique on each server.
</p>
</li>
<li class="listitem">
<p>
Verify that the replica is running. Use
<a class="link" href="show-replica-status.html" title="15.7.7.35 SHOW REPLICA STATUS Statement">
<code class="literal">
SHOW REPLICA STATUS
</code>
</a>
to check
whether the
<code class="literal">
Replica_IO_Running
</code>
and
<code class="literal">
Replica_SQL_Running
</code>
values are both
<code class="literal">
Yes
</code>
. If not, verify the options that were
used when starting the replica server. For example,
<a class="link" href="replication-options-replica.html#sysvar_skip_replica_start">
<code class="option">
--skip-replica-start
</code>
</a>
prevents
the replication threads from starting until you issue a
<a class="link" href="start-replica.html" title="15.4.2.4 START REPLICA Statement">
<code class="literal">
START REPLICA
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
If the replica is running, check whether it established a
connection to the source. Use
<a class="link" href="show-processlist.html" title="15.7.7.31 SHOW PROCESSLIST Statement">
<code class="literal">
SHOW
PROCESSLIST
</code>
</a>
, find the I/O (receiver) and SQL
(applier) threads and check their
<code class="literal">
State
</code>
column to see what they display. See
<a class="xref" href="replication-threads.html" title="19.2.3 Replication Threads">
Section 19.2.3, “Replication Threads”
</a>
. If the receiver thread
state says
<code class="literal">
Connecting to master
</code>
, check the
following:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Verify the privileges for the replication user on the
source.
</p>
</li>
<li class="listitem">
<p>
Check that the host name of the source is correct and that
you are using the correct port to connect to the source.
The port used for replication is the same as used for
client network communication (the default is
<code class="literal">
3306
</code>
). For the host name, ensure that
the name resolves to the correct IP address.
</p>
</li>
<li class="listitem">
<p>
Check the configuration file to see whether the
<a class="link" href="server-system-variables.html#sysvar_skip_networking">
<code class="literal">
skip_networking
</code>
</a>
system
variable has been enabled on the source or replica to
disable networking. If so, comment the setting or remove
it.
</p>
</li>
<li class="listitem">
<p>
If the source has a firewall or IP filtering
configuration, ensure that the network port being used for
MySQL is not being filtered.
</p>
</li>
<li class="listitem">
<p>
Check that you can reach the source by using
<code class="literal">
ping
</code>
or
<code class="literal">
traceroute
</code>
/
<code class="literal">
tracert
</code>
to reach the host.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
If the replica was running previously but has stopped, the
reason usually is that some statement that succeeded on the
source failed on the replica. This should never happen if you
have taken a proper snapshot of the source, and never modified
the data on the replica outside of the replication threads. If
the replica stops unexpectedly, it is a bug or you have
encountered one of the known replication limitations described
in
<a class="xref" href="replication-features.html" title="19.5.1 Replication Features and Issues">
Section 19.5.1, “Replication Features and Issues”
</a>
. If it is a bug, see
<a class="xref" href="replication-bugs.html" title="19.5.5 How to Report Replication Bugs or Problems">
Section 19.5.5, “How to Report Replication Bugs or Problems”
</a>
, for instructions on how to
report it.
</p>
</li>
<li class="listitem">
<p>
If a statement that succeeded on the source refuses to run on
the replica, try the following procedure if it is not feasible
to do a full database resynchronization by deleting the
replica's databases and copying a new snapshot from the
source:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Determine whether the affected table on the replica is
different from the source table. Try to understand how
this happened. Then make the replica's table identical to
the source's and run
<a class="link" href="start-replica.html" title="15.4.2.4 START REPLICA Statement">
<code class="literal">
START
REPLICA
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
If the preceding step does not work or does not apply, try
to understand whether it would be safe to make the update
manually (if needed) and then ignore the next statement
from the source.
</p>
</li>
<li class="listitem">
<p>
If you decide that the replica can skip the next statement
from the source, issue the following statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42128955"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> sql_replica_skip_counter <span class="token operator">=</span> <em class="replaceable">N</em><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">START</span> <span class="token keyword">REPLICA</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The value of
<em class="replaceable">
<code>
N
</code>
</em>
should be 1 if
the next statement from the source does not use
<code class="literal">
AUTO_INCREMENT
</code>
or
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
.
Otherwise, the value should be 2. The reason for using a
value of 2 for statements that use
<code class="literal">
AUTO_INCREMENT
</code>
or
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
is that
they take two events in the binary log of the source.
</p>
</li>
<li class="listitem">
<p>
If you are sure that the replica started out perfectly
synchronized with the source, and that no one has updated
the tables involved outside of the replication threads,
then presumably the discrepancy is the result of a bug. If
you are running the most recent version of MySQL, please
report the problem. If you are running an older version,
try upgrading to the latest production release to
determine whether the problem persists.
</p>
</li>
</ol>
</div>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/show-replicas.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="show-replicas">
</a>
15.7.7.36 SHOW REPLICAS Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045169370768">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa67801168"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">REPLICAS</span></code></pre>
</div>
<p>
Displays a list of replicas currently registered with the
source.
<code class="literal">
SHOW REPLICAS
</code>
requires the
<a class="link" href="privileges-provided.html#priv_replication-slave">
<code class="literal">
REPLICATION SLAVE
</code>
</a>
privilege.
</p>
<p>
<code class="literal">
SHOW REPLICAS
</code>
should be executed on a server
that acts as a replication source. The statement displays
information about servers that are or have been connected as
replicas, with each row of the result corresponding to one
replica server, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa58843368"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">REPLICAS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Server_id <span class="token punctuation">|</span> Host <span class="token punctuation">|</span> Port <span class="token punctuation">|</span> Source_id <span class="token punctuation">|</span> Replica_UUID <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> iconnect2 <span class="token punctuation">|</span> 3306 <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span> 14cb6624<span class="token punctuation">-</span>7f93<span class="token punctuation">-</span>11e0<span class="token punctuation">-</span>b2c0<span class="token punctuation">-</span>c80aa9429562 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 21 <span class="token punctuation">|</span> athena <span class="token punctuation">|</span> 3306 <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span> 07af4990<span class="token punctuation">-</span>f41f<span class="token punctuation">-</span>11df<span class="token punctuation">-</span>a566<span class="token punctuation">-</span>7ac56fdaf645 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Server_id
</code>
: The unique server ID of the
replica server, as configured in the replica server's
option file, or on the command line with
<a class="link" href="replication-options.html#sysvar_server_id">
<code class="option">
--server-id=
<em class="replaceable">
<code>
value
</code>
</em>
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Host
</code>
: The host name of the replica
server, as specified on the replica with the
<a class="link" href="replication-options-replica.html#sysvar_report_host">
<code class="option">
--report-host
</code>
</a>
option. This
can differ from the machine name as configured in the
operating system.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
User
</code>
: The replica server user name, as
specified on the replica with the
<a class="link" href="replication-options-replica.html#sysvar_report_user">
<code class="option">
--report-user
</code>
</a>
option.
Statement output includes this column only if the source
server is started with the
<a class="link" href="replication-options-source.html#option_mysqld_show-replica-auth-info">
<code class="option">
--show-replica-auth-info
</code>
</a>
option.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Password
</code>
: The replica server password, as
specified on the replica with the
<a class="link" href="replication-options-replica.html#sysvar_report_password">
<code class="option">
--report-password
</code>
</a>
option.
Statement output includes this column only if the source
server is started with the
<a class="link" href="replication-options-source.html#option_mysqld_show-replica-auth-info">
<code class="option">
--show-replica-auth-info
</code>
</a>
option.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Port
</code>
: The port on the source to which the
replica server is listening, as specified on the replica
with the
<a class="link" href="replication-options-replica.html#sysvar_report_port">
<code class="option">
--report-port
</code>
</a>
option.
</p>
<p>
A zero in this column means that the replica port
(
<a class="link" href="replication-options-replica.html#sysvar_report_port">
<code class="option">
--report-port
</code>
</a>
) was not set.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Source_id
</code>
: The unique server ID of the
source server that the replica server is replicating from.
This is the server ID of the server on which
<code class="literal">
SHOW
REPLICAS
</code>
is executed, so this same value is listed
for each row in the result.
</p>
</li>
<li class="listitem">
<p>
<a class="indexterm" name="idm46045169340224">
</a>
<code class="literal">
Replica_UUID
</code>
: The globally unique ID of
this replica, as generated on the replica and found in the
replica's
<code class="filename">
auto.cnf
</code>
file.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/privileges-provided.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="privileges-provided">
</a>
8.2.2 Privileges Provided by MySQL
</h3>
</div>
</div>
</div>
<p>
The privileges granted to a MySQL account determine which
operations the account can perform. MySQL privileges differ in the
contexts in which they apply and at different levels of operation:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Administrative privileges enable users to manage operation of
the MySQL server. These privileges are global because they are
not specific to a particular database.
</p>
</li>
<li class="listitem">
<p>
Database privileges apply to a database and to all objects
within it. These privileges can be granted for specific
databases, or globally so that they apply to all databases.
</p>
</li>
<li class="listitem">
<p>
Privileges for database objects such as tables, indexes,
views, and stored routines can be granted for specific objects
within a database, for all objects of a given type within a
database (for example, all tables in a database), or globally
for all objects of a given type in all databases.
</p>
</li>
</ul>
</div>
<p>
Privileges also differ in terms of whether they are static (built
in to the server) or dynamic (defined at runtime). Whether a
privilege is static or dynamic affects its availability to be
granted to user accounts and roles. For information about the
differences between static and dynamic privileges, see
<a class="xref" href="privileges-provided.html#static-dynamic-privileges" title="Static Versus Dynamic Privileges">
Static Versus Dynamic Privileges
</a>
.)
</p>
<p>
Information about account privileges is stored in the grant tables
in the
<code class="literal">
mysql
</code>
system database. For a description
of the structure and contents of these tables, see
<a class="xref" href="grant-tables.html" title="8.2.3 Grant Tables">
Section 8.2.3, “Grant Tables”
</a>
. The MySQL server reads the
contents of the grant tables into memory when it starts, and
reloads them under the circumstances indicated in
<a class="xref" href="privilege-changes.html" title="8.2.13 When Privilege Changes Take Effect">
Section 8.2.13, “When Privilege Changes Take Effect”
</a>
. The server bases
access-control decisions on the in-memory copies of the grant
tables.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
Some MySQL releases introduce changes to the grant tables to add
new privileges or features. To make sure that you can take
advantage of any new capabilities, update your grant tables to
the current structure whenever you upgrade MySQL. See
<a class="xref" href="upgrading.html" title="Chapter 3 Upgrading MySQL">
Chapter 3,
<i>
Upgrading MySQL
</i>
</a>
.
</p>
</div>
<p>
The following sections summarize the available privileges, provide
more detailed descriptions of each privilege, and offer usage
guidelines.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#privileges-provided-summary" title="Summary of Available Privileges">
Summary of Available Privileges
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#privileges-provided-static" title="Static Privilege Descriptions">
Static Privilege Descriptions
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#privileges-provided-dynamic" title="Dynamic Privilege Descriptions">
Dynamic Privilege Descriptions
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#privileges-provided-guidelines" title="Privilege-Granting Guidelines">
Privilege-Granting Guidelines
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#static-dynamic-privileges" title="Static Versus Dynamic Privileges">
Static Versus Dynamic Privileges
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="privileges-provided.html#dynamic-privileges-migration-from-super" title="Migrating Accounts from SUPER to Dynamic Privileges">
Migrating Accounts from SUPER to Dynamic Privileges
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="privileges-provided-summary">
</a>
Summary of Available Privileges
</h4>
</div>
</div>
</div>
<p>
The following table shows the static privilege names used in
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements, along with the
column name associated with each privilege in the grant tables
and the context in which the privilege applies.
</p>
<div class="table">
<a name="idm46045252210080">
</a>
<p class="title">
<b>
Table 8.2 Permissible Static Privileges for GRANT and REVOKE
</b>
</p>
<div class="table-contents">
<table>
<colgroup>
<col style="width: 30%"/>
<col style="width: 33%"/>
<col style="width: 37%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Privilege
</th>
<th scope="col">
Grant Table Column
</th>
<th scope="col">
Context
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_all">
<code class="literal">
ALL [PRIVILEGES]
</code>
</a>
</th>
<td>
Synonym for
<span class="quote">
“
<span class="quote">
all privileges
</span>
”
</span>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_alter">
<code class="literal">
ALTER
</code>
</a>
</th>
<td>
<code class="literal">
Alter_priv
</code>
</td>
<td>
Tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_alter-routine">
<code class="literal">
ALTER ROUTINE
</code>
</a>
</th>
<td>
<code class="literal">
Alter_routine_priv
</code>
</td>
<td>
Stored routines
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create">
<code class="literal">
CREATE
</code>
</a>
</th>
<td>
<code class="literal">
Create_priv
</code>
</td>
<td>
Databases, tables, or indexes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-role">
<code class="literal">
CREATE ROLE
</code>
</a>
</th>
<td>
<code class="literal">
Create_role_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-routine">
<code class="literal">
CREATE ROUTINE
</code>
</a>
</th>
<td>
<code class="literal">
Create_routine_priv
</code>
</td>
<td>
Stored routines
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-tablespace">
<code class="literal">
CREATE TABLESPACE
</code>
</a>
</th>
<td>
<code class="literal">
Create_tablespace_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-temporary-tables">
<code class="literal">
CREATE TEMPORARY TABLES
</code>
</a>
</th>
<td>
<code class="literal">
Create_tmp_table_priv
</code>
</td>
<td>
Tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
</th>
<td>
<code class="literal">
Create_user_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_create-view">
<code class="literal">
CREATE VIEW
</code>
</a>
</th>
<td>
<code class="literal">
Create_view_priv
</code>
</td>
<td>
Views
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_delete">
<code class="literal">
DELETE
</code>
</a>
</th>
<td>
<code class="literal">
Delete_priv
</code>
</td>
<td>
Tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
</th>
<td>
<code class="literal">
Drop_priv
</code>
</td>
<td>
Databases, tables, or views
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_drop-role">
<code class="literal">
DROP ROLE
</code>
</a>
</th>
<td>
<code class="literal">
Drop_role_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_event">
<code class="literal">
EVENT
</code>
</a>
</th>
<td>
<code class="literal">
Event_priv
</code>
</td>
<td>
Databases
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_execute">
<code class="literal">
EXECUTE
</code>
</a>
</th>
<td>
<code class="literal">
Execute_priv
</code>
</td>
<td>
Stored routines
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
</th>
<td>
<code class="literal">
File_priv
</code>
</td>
<td>
File access on server host
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_grant-option">
<code class="literal">
GRANT OPTION
</code>
</a>
</th>
<td>
<code class="literal">
Grant_priv
</code>
</td>
<td>
Databases, tables, or stored routines
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_index">
<code class="literal">
INDEX
</code>
</a>
</th>
<td>
<code class="literal">
Index_priv
</code>
</td>
<td>
Tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
</th>
<td>
<code class="literal">
Insert_priv
</code>
</td>
<td>
Tables or columns
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_lock-tables">
<code class="literal">
LOCK TABLES
</code>
</a>
</th>
<td>
<code class="literal">
Lock_tables_priv
</code>
</td>
<td>
Databases
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
</th>
<td>
<code class="literal">
Process_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_proxy">
<code class="literal">
PROXY
</code>
</a>
</th>
<td>
See
<code class="literal">
proxies_priv
</code>
table
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_references">
<code class="literal">
REFERENCES
</code>
</a>
</th>
<td>
<code class="literal">
References_priv
</code>
</td>
<td>
Databases or tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_reload">
<code class="literal">
RELOAD
</code>
</a>
</th>
<td>
<code class="literal">
Reload_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_replication-client">
<code class="literal">
REPLICATION CLIENT
</code>
</a>
</th>
<td>
<code class="literal">
Repl_client_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_replication-slave">
<code class="literal">
REPLICATION SLAVE
</code>
</a>
</th>
<td>
<code class="literal">
Repl_slave_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
</th>
<td>
<code class="literal">
Select_priv
</code>
</td>
<td>
Tables or columns
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_show-databases">
<code class="literal">
SHOW DATABASES
</code>
</a>
</th>
<td>
<code class="literal">
Show_db_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_show-view">
<code class="literal">
SHOW VIEW
</code>
</a>
</th>
<td>
<code class="literal">
Show_view_priv
</code>
</td>
<td>
Views
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_shutdown">
<code class="literal">
SHUTDOWN
</code>
</a>
</th>
<td>
<code class="literal">
Shutdown_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
</th>
<td>
<code class="literal">
Super_priv
</code>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_trigger">
<code class="literal">
TRIGGER
</code>
</a>
</th>
<td>
<code class="literal">
Trigger_priv
</code>
</td>
<td>
Tables
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
</th>
<td>
<code class="literal">
Update_priv
</code>
</td>
<td>
Tables or columns
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="privileges-provided.html#priv_usage">
<code class="literal">
USAGE
</code>
</a>
</th>
<td>
Synonym for
<span class="quote">
“
<span class="quote">
no privileges
</span>
”
</span>
</td>
<td>
Server administration
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 647px;">
<thead>
<tr>
<th scope="col" style="width: 193.875px;">
Privilege
</th>
<th scope="col" style="width: 213.266px;">
Grant Table Column
</th>
<th scope="col" style="width: 239.156px;">
Context
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
<p>
The following table shows the dynamic privilege names used in
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements, along with the
context in which the privilege applies.
</p>
<div class="table">
<a name="idm46045252038592">
</a>
<p class="title">
<b>
Table 8.3 Permissible Dynamic Privileges for GRANT and REVOKE
</b>
</p>
<div class="table-contents">
<table>
<colgroup>
<col style="width: 35%"/>
<col style="width: 45%"/>
</colgroup>
<thead>
<tr>
<th>
Privilege
</th>
<th>
Context
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_allow-nonexistent-definer">
<code class="literal">
ALLOW_NONEXISTENT_DEFINER
</code>
</a>
</td>
<td>
Orphan object protection
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_application-password-admin">
<code class="literal">
APPLICATION_PASSWORD_ADMIN
</code>
</a>
</td>
<td>
Dual password administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_audit-abort-exempt">
<code class="literal">
AUDIT_ABORT_EXEMPT
</code>
</a>
</td>
<td>
Allow queries blocked by audit log filter
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_audit-admin">
<code class="literal">
AUDIT_ADMIN
</code>
</a>
</td>
<td>
Audit log administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_authentication-policy-admin">
<code class="literal">
AUTHENTICATION_POLICY_ADMIN
</code>
</a>
</td>
<td>
Authentication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_backup-admin">
<code class="literal">
BACKUP_ADMIN
</code>
</a>
</td>
<td>
Backup administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_binlog-admin">
<code class="literal">
BINLOG_ADMIN
</code>
</a>
</td>
<td>
Backup and Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_binlog-encryption-admin">
<code class="literal">
BINLOG_ENCRYPTION_ADMIN
</code>
</a>
</td>
<td>
Backup and Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_clone-admin">
<code class="literal">
CLONE_ADMIN
</code>
</a>
</td>
<td>
Clone administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_encryption-key-admin">
<code class="literal">
ENCRYPTION_KEY_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_firewall-admin">
<code class="literal">
FIREWALL_ADMIN
</code>
</a>
</td>
<td>
Firewall administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_firewall-exempt">
<code class="literal">
FIREWALL_EXEMPT
</code>
</a>
</td>
<td>
Firewall administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_firewall-user">
<code class="literal">
FIREWALL_USER
</code>
</a>
</td>
<td>
Firewall administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_flush-optimizer-costs">
<code class="literal">
FLUSH_OPTIMIZER_COSTS
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_flush-privileges">
<code class="literal">
FLUSH_PRIVILEGES
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_flush-status">
<code class="literal">
FLUSH_STATUS
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_flush-tables">
<code class="literal">
FLUSH_TABLES
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_flush-user-resources">
<code class="literal">
FLUSH_USER_RESOURCES
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_group-replication-admin">
<code class="literal">
GROUP_REPLICATION_ADMIN
</code>
</a>
</td>
<td>
Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_group-replication-stream">
<code class="literal">
GROUP_REPLICATION_STREAM
</code>
</a>
</td>
<td>
Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_innodb-redo-log-archive">
<code class="literal">
INNODB_REDO_LOG_ARCHIVE
</code>
</a>
</td>
<td>
Redo log archiving administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_innodb-redo-log-enable">
<code class="literal">
INNODB_REDO_LOG_ENABLE
</code>
</a>
</td>
<td>
Redo log administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_masking-dictionaries-admin">
<code class="literal">
MASKING_DICTIONARIES_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_ndb-stored-user">
<code class="literal">
NDB_STORED_USER
</code>
</a>
</td>
<td>
NDB Cluster
</td>
</tr>
<tr>
<td scope="row">
<a class="link" href="privileges-provided.html#priv_optimize-local-table">
<code class="literal">
OPTIMIZE_LOCAL_TABLE
</code>
</a>
</td>
<td>
<a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
<code class="literal">
OPTIMIZE LOCAL
TABLE
</code>
</a>
statements
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_passwordless-user-admin">
<code class="literal">
PASSWORDLESS_USER_ADMIN
</code>
</a>
</td>
<td>
Authentication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_persist-ro-variables-admin">
<code class="literal">
PERSIST_RO_VARIABLES_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_replication-applier">
<code class="literal">
REPLICATION_APPLIER
</code>
</a>
</td>
<td>
<code class="literal">
PRIVILEGE_CHECKS_USER
</code>
for a replication channel
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
</td>
<td>
Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_resource-group-admin">
<code class="literal">
RESOURCE_GROUP_ADMIN
</code>
</a>
</td>
<td>
Resource group administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_resource-group-user">
<code class="literal">
RESOURCE_GROUP_USER
</code>
</a>
</td>
<td>
Resource group administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_role-admin">
<code class="literal">
ROLE_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_sensitive-variables-observer">
<code class="literal">
SENSITIVE_VARIABLES_OBSERVER
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_set-any-definer">
<code class="literal">
SET_ANY_DEFINER
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_show-routine">
<code class="literal">
SHOW_ROUTINE
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_skip-query-rewrite">
<code class="literal">
SKIP_QUERY_REWRITE
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_table-encryption-admin">
<code class="literal">
TABLE_ENCRYPTION_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_telemetry-log-admin">
<code class="literal">
TELEMETRY_LOG_ADMIN
</code>
</a>
</td>
<td>
Telemetry log administration for HeatWave on AWS
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_tp-connection-admin">
<code class="literal">
TP_CONNECTION_ADMIN
</code>
</a>
</td>
<td>
Thread pool administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_transaction-gtid-tag">
<code class="literal">
TRANSACTION_GTID_TAG
</code>
</a>
</td>
<td>
Replication administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_version-token-admin">
<code class="literal">
VERSION_TOKEN_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
<tr>
<td>
<a class="link" href="privileges-provided.html#priv_xa-recover-admin">
<code class="literal">
XA_RECOVER_ADMIN
</code>
</a>
</td>
<td>
Server administration
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th style="width: 322.875px;">
Privilege
</th>
<th style="width: 415.125px;">
Context
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="privileges-provided-static">
</a>
Static Privilege Descriptions
</h4>
</div>
</div>
</div>
<p>
Static privileges are built in to the server, in contrast to
dynamic privileges, which are defined at runtime. The following
list describes each static privilege available in MySQL.
</p>
<p>
Particular SQL statements might have more specific privilege
requirements than indicated here. If so, the description for the
statement in question provides the details.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="priv_all">
</a>
<a class="link" href="privileges-provided.html#priv_all">
<code class="literal">
ALL
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_all">
<code class="literal">
ALL
PRIVILEGES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251878592">
</a>
<a class="indexterm" name="idm46045251877136">
</a>
<a class="indexterm" name="idm46045251876064">
</a>
<a class="indexterm" name="idm46045251874576">
</a>
<p>
These privilege specifiers are shorthand for
<span class="quote">
“
<span class="quote">
all
privileges available at a given privilege level
</span>
”
</span>
(except
<a class="link" href="privileges-provided.html#priv_grant-option">
<code class="literal">
GRANT OPTION
</code>
</a>
). For
example, granting
<a class="link" href="privileges-provided.html#priv_all">
<code class="literal">
ALL
</code>
</a>
at the
global or table level grants all global privileges or all
table-level privileges, respectively.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_alter">
</a>
<a class="link" href="privileges-provided.html#priv_alter">
<code class="literal">
ALTER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251867552">
</a>
<a class="indexterm" name="idm46045251866064">
</a>
<p>
Enables use of the
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER
TABLE
</code>
</a>
statement to change the structure of tables.
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
also requires the
<a class="link" href="privileges-provided.html#priv_create">
<code class="literal">
CREATE
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
privileges. Renaming a
table requires
<a class="link" href="privileges-provided.html#priv_alter">
<code class="literal">
ALTER
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
on the old table,
<a class="link" href="privileges-provided.html#priv_create">
<code class="literal">
CREATE
</code>
</a>
, and
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
on the new table.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_alter-routine">
</a>
<a class="link" href="privileges-provided.html#priv_alter-routine">
<code class="literal">
ALTER ROUTINE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251852176">
</a>
<a class="indexterm" name="idm46045251850688">
</a>
<p>
Enables use of statements that alter or drop stored routines
(stored procedures and functions). For routines that fall
within the scope at which the privilege is granted and for
which the user is not the user named as the routine
<code class="literal">
DEFINER
</code>
, also enables access to routine
properties other than the routine definition.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create">
</a>
<a class="link" href="privileges-provided.html#priv_create">
<code class="literal">
CREATE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251845792">
</a>
<a class="indexterm" name="idm46045251844304">
</a>
<p>
Enables use of statements that create new databases and
tables.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-role">
</a>
<a class="link" href="privileges-provided.html#priv_create-role">
<code class="literal">
CREATE ROLE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251840336">
</a>
<a class="indexterm" name="idm46045251838848">
</a>
<p>
Enables use of the
<a class="link" href="create-role.html" title="15.7.1.2 CREATE ROLE Statement">
<code class="literal">
CREATE
ROLE
</code>
</a>
statement. (The
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE
USER
</code>
</a>
privilege also enables use of the
<a class="link" href="create-role.html" title="15.7.1.2 CREATE ROLE Statement">
<code class="literal">
CREATE ROLE
</code>
</a>
statement.) See
<a class="xref" href="roles.html" title="8.2.10 Using Roles">
Section 8.2.10, “Using Roles”
</a>
.
</p>
<p>
The
<a class="link" href="privileges-provided.html#priv_create-role">
<code class="literal">
CREATE ROLE
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_drop-role">
<code class="literal">
DROP ROLE
</code>
</a>
privileges are not
as powerful as
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
because they can be used only to create and drop accounts.
They cannot be used as
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE
USER
</code>
</a>
can be modify account attributes or rename
accounts. See
<a class="xref" href="roles.html#role-user-interchangeability" title="User and Role Interchangeability">
User and Role Interchangeability
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-routine">
</a>
<a class="link" href="privileges-provided.html#priv_create-routine">
<code class="literal">
CREATE ROUTINE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251823984">
</a>
<a class="indexterm" name="idm46045251822496">
</a>
<p>
Enables use of statements that create stored routines
(stored procedures and functions). For routines that fall
within the scope at which the privilege is granted and for
which the user is not the user named as the routine
<code class="literal">
DEFINER
</code>
, also enables access to routine
properties other than the routine definition.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-tablespace">
</a>
<a class="link" href="privileges-provided.html#priv_create-tablespace">
<code class="literal">
CREATE TABLESPACE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251817584">
</a>
<a class="indexterm" name="idm46045251816096">
</a>
<p>
Enables use of statements that create, alter, or drop
tablespaces and log file groups.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-temporary-tables">
</a>
<a class="link" href="privileges-provided.html#priv_create-temporary-tables">
<code class="literal">
CREATE TEMPORARY TABLES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251811968">
</a>
<a class="indexterm" name="idm46045251810480">
</a>
<p>
Enables the creation of temporary tables using the
<a class="link" href="create-temporary-table.html" title="15.1.20.2 CREATE TEMPORARY TABLE Statement">
<code class="literal">
CREATE TEMPORARY TABLE
</code>
</a>
statement.
</p>
<a class="indexterm" name="idm46045251807648">
</a>
<a class="indexterm" name="idm46045251806160">
</a>
<p>
After a session has created a temporary table, the server
performs no further privilege checks on the table. The
creating session can perform any operation on the table,
such as
<a class="link" href="drop-table.html" title="15.1.32 DROP TABLE Statement">
<code class="literal">
DROP TABLE
</code>
</a>
,
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, or
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
. For more information,
see
<a class="xref" href="create-temporary-table.html" title="15.1.20.2 CREATE TEMPORARY TABLE Statement">
Section 15.1.20.2, “CREATE TEMPORARY TABLE Statement”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-user">
</a>
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251796416">
</a>
<a class="indexterm" name="idm46045251794928">
</a>
<p>
Enables use of the
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER
USER
</code>
</a>
,
<a class="link" href="create-role.html" title="15.7.1.2 CREATE ROLE Statement">
<code class="literal">
CREATE ROLE
</code>
</a>
,
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
,
<a class="link" href="drop-role.html" title="15.7.1.4 DROP ROLE Statement">
<code class="literal">
DROP ROLE
</code>
</a>
,
<a class="link" href="drop-user.html" title="15.7.1.5 DROP USER Statement">
<code class="literal">
DROP USER
</code>
</a>
,
<a class="link" href="rename-user.html" title="15.7.1.7 RENAME USER Statement">
<code class="literal">
RENAME USER
</code>
</a>
, and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE ALL
PRIVILEGES
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_create-view">
</a>
<a class="link" href="privileges-provided.html#priv_create-view">
<code class="literal">
CREATE VIEW
</code>
</a>
</p>
<a class="indexterm" name="idm46045251782480">
</a>
<a class="indexterm" name="idm46045251780992">
</a>
<p>
Enables use of the
<a class="link" href="create-view.html" title="15.1.23 CREATE VIEW Statement">
<code class="literal">
CREATE
VIEW
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_delete">
</a>
<a class="link" href="privileges-provided.html#priv_delete">
<code class="literal">
DELETE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251775856">
</a>
<a class="indexterm" name="idm46045251774368">
</a>
<p>
Enables rows to be deleted from tables in a database.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_drop">
</a>
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
</p>
<a class="indexterm" name="idm46045251770480">
</a>
<a class="indexterm" name="idm46045251768992">
</a>
<p>
Enables use of statements that drop (remove) existing
databases, tables, and views. The
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
privilege is required to
use the
<code class="literal">
ALTER TABLE ... DROP PARTITION
</code>
statement on a partitioned table. The
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
privilege is also
required for
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_drop-role">
</a>
<a class="link" href="privileges-provided.html#priv_drop-role">
<code class="literal">
DROP ROLE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251760448">
</a>
<a class="indexterm" name="idm46045251758960">
</a>
<p>
Enables use of the
<a class="link" href="drop-role.html" title="15.7.1.4 DROP ROLE Statement">
<code class="literal">
DROP ROLE
</code>
</a>
statement. (The
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
privilege also enables use of the
<a class="link" href="drop-role.html" title="15.7.1.4 DROP ROLE Statement">
<code class="literal">
DROP
ROLE
</code>
</a>
statement.) See
<a class="xref" href="roles.html" title="8.2.10 Using Roles">
Section 8.2.10, “Using Roles”
</a>
.
</p>
<p>
The
<a class="link" href="privileges-provided.html#priv_create-role">
<code class="literal">
CREATE ROLE
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_drop-role">
<code class="literal">
DROP ROLE
</code>
</a>
privileges are not
as powerful as
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
because they can be used only to create and drop accounts.
They cannot be used as
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE
USER
</code>
</a>
can be modify account attributes or rename
accounts. See
<a class="xref" href="roles.html#role-user-interchangeability" title="User and Role Interchangeability">
User and Role Interchangeability
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_event">
</a>
<a class="link" href="privileges-provided.html#priv_event">
<code class="literal">
EVENT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251744400">
</a>
<a class="indexterm" name="idm46045251742912">
</a>
<p>
Enables use of statements that create, alter, drop, or
display events for the Event Scheduler.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_execute">
</a>
<a class="link" href="privileges-provided.html#priv_execute">
<code class="literal">
EXECUTE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251738912">
</a>
<a class="indexterm" name="idm46045251737424">
</a>
<p>
Enables use of statements that execute stored routines
(stored procedures and functions). For routines that fall
within the scope at which the privilege is granted and for
which the user is not the user named as the routine
<code class="literal">
DEFINER
</code>
, also enables access to routine
properties other than the routine definition.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_file">
</a>
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251732464">
</a>
<a class="indexterm" name="idm46045251730976">
</a>
<p>
Affects the following operations and server behaviors:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Enables reading and writing files on the server host
using the
<a class="link" href="load-data.html" title="15.2.9 LOAD DATA Statement">
<code class="literal">
LOAD DATA
</code>
</a>
and
<a class="link" href="select-into.html" title="15.2.13.1 SELECT ... INTO Statement">
<code class="literal">
SELECT ...
INTO OUTFILE
</code>
</a>
statements and the
<a class="link" href="string-functions.html#function_load-file">
<code class="literal">
LOAD_FILE()
</code>
</a>
function. A
user who has the
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
privilege can read any file on the server host that is
either world-readable or readable by the MySQL server.
(This implies the user can read any file in any database
directory, because the server can access any of those
files.)
</p>
</li>
<li class="listitem">
<p>
Enables creating new files in any directory where the
MySQL server has write access. This includes the
server's data directory containing the files that
implement the privilege tables.
</p>
</li>
<li class="listitem">
<p>
Enables use of the
<code class="literal">
DATA DIRECTORY
</code>
or
<code class="literal">
INDEX DIRECTORY
</code>
table option for the
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statement.
</p>
</li>
</ul>
</div>
<p>
As a security measure, the server does not overwrite
existing files.
</p>
<p>
To limit the location in which files can be read and
written, set the
<a class="link" href="server-system-variables.html#sysvar_secure_file_priv">
<code class="literal">
secure_file_priv
</code>
</a>
system
variable to a specific directory. See
<a class="xref" href="server-system-variables.html" title="7.1.8 Server System Variables">
Section 7.1.8, “Server System Variables”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_grant-option">
</a>
<a class="link" href="privileges-provided.html#priv_grant-option">
<code class="literal">
GRANT OPTION
</code>
</a>
</p>
<a class="indexterm" name="idm46045251712912">
</a>
<a class="indexterm" name="idm46045251711424">
</a>
<p>
Enables you to grant to or revoke from other users those
privileges that you yourself possess.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_index">
</a>
<a class="link" href="privileges-provided.html#priv_index">
<code class="literal">
INDEX
</code>
</a>
</p>
<a class="indexterm" name="idm46045251707424">
</a>
<a class="indexterm" name="idm46045251705936">
</a>
<p>
Enables use of statements that create or drop (remove)
indexes.
<a class="link" href="privileges-provided.html#priv_index">
<code class="literal">
INDEX
</code>
</a>
applies to
existing tables. If you have the
<a class="link" href="privileges-provided.html#priv_create">
<code class="literal">
CREATE
</code>
</a>
privilege for a table,
you can include index definitions in the
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_insert">
</a>
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251698144">
</a>
<a class="indexterm" name="idm46045251696656">
</a>
<p>
Enables rows to be inserted into tables in a database.
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
is also required for
the
<a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
<code class="literal">
ANALYZE TABLE
</code>
</a>
,
<a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
<code class="literal">
OPTIMIZE TABLE
</code>
</a>
, and
<a class="link" href="repair-table.html" title="15.7.3.5 REPAIR TABLE Statement">
<code class="literal">
REPAIR TABLE
</code>
</a>
table-maintenance statements.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_lock-tables">
</a>
<a class="link" href="privileges-provided.html#priv_lock-tables">
<code class="literal">
LOCK TABLES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251687728">
</a>
<a class="indexterm" name="idm46045251686240">
</a>
<p>
Enables use of explicit
<a class="link" href="lock-tables.html" title="15.3.6 LOCK TABLES and UNLOCK TABLES Statements">
<code class="literal">
LOCK
TABLES
</code>
</a>
statements to lock tables for which you
have the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege.
This includes use of write locks, which prevents other
sessions from reading the locked table.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_process">
</a>
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
</p>
<a class="indexterm" name="idm46045251679696">
</a>
<a class="indexterm" name="idm46045251678208">
</a>
<p>
The
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege
controls access to information about threads executing
within the server (that is, information about statements
being executed by sessions). Thread information available
using the
<a class="link" href="show-processlist.html" title="15.7.7.31 SHOW PROCESSLIST Statement">
<code class="literal">
SHOW PROCESSLIST
</code>
</a>
statement, the
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin processlist
</strong>
</span>
</a>
command, the Information Schema
<a class="link" href="information-schema-processlist-table.html" title="28.3.23 The INFORMATION_SCHEMA PROCESSLIST Table">
<code class="literal">
PROCESSLIST
</code>
</a>
table, and the
Performance Schema
<a class="link" href="performance-schema-processlist-table.html" title="29.12.22.7 The processlist Table">
<code class="literal">
processlist
</code>
</a>
table is accessible as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
With the
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege, a user has access to information about all
threads, even those belonging to other users.
</p>
</li>
<li class="listitem">
<p>
Without the
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege, nonanonymous users have access to information
about their own threads but not threads for other users,
and anonymous users have no access to thread
information.
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The Performance Schema
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table also provides
thread information, but table access uses a different
privilege model. See
<a class="xref" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
Section 29.12.22.8, “The threads Table”
</a>
.
</p>
</div>
<p>
The
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege also
enables use of the
<a class="link" href="show-engine.html" title="15.7.7.16 SHOW ENGINE Statement">
<code class="literal">
SHOW
ENGINE
</code>
</a>
statement, access to the
<code class="literal">
INFORMATION_SCHEMA
</code>
<code class="literal">
InnoDB
</code>
tables (tables with names that
begin with
<code class="literal">
INNODB_
</code>
), and access to the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-files-table.html" title="28.3.15 The INFORMATION_SCHEMA FILES Table">
<code class="literal">
FILES
</code>
</a>
table.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_proxy">
</a>
<a class="link" href="privileges-provided.html#priv_proxy">
<code class="literal">
PROXY
</code>
</a>
</p>
<a class="indexterm" name="idm46045251652624">
</a>
<a class="indexterm" name="idm46045251651136">
</a>
<p>
Enables one user to impersonate or become known as another
user. See
<a class="xref" href="proxy-users.html" title="8.2.19 Proxy Users">
Section 8.2.19, “Proxy Users”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_references">
</a>
<a class="link" href="privileges-provided.html#priv_references">
<code class="literal">
REFERENCES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251646496">
</a>
<a class="indexterm" name="idm46045251645008">
</a>
<p>
Creation of a foreign key constraint requires the
<a class="link" href="privileges-provided.html#priv_references">
<code class="literal">
REFERENCES
</code>
</a>
privilege for the
parent table.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_reload">
</a>
<a class="link" href="privileges-provided.html#priv_reload">
<code class="literal">
RELOAD
</code>
</a>
</p>
<a class="indexterm" name="idm46045251639856">
</a>
<a class="indexterm" name="idm46045251638368">
</a>
<p>
The
<a class="link" href="privileges-provided.html#priv_reload">
<code class="literal">
RELOAD
</code>
</a>
enables the
following operations:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Use of the
<a class="link" href="flush.html" title="15.7.8.3 FLUSH Statement">
<code class="literal">
FLUSH
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
Use of
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin
</strong>
</span>
</a>
commands that are
equivalent to
<a class="link" href="flush.html" title="15.7.8.3 FLUSH Statement">
<code class="literal">
FLUSH
</code>
</a>
operations:
<code class="literal">
flush-hosts
</code>
,
<code class="literal">
flush-logs
</code>
,
<code class="literal">
flush-privileges
</code>
,
<code class="literal">
flush-status
</code>
,
<code class="literal">
flush-tables
</code>
,
<code class="literal">
refresh
</code>
, and
<code class="literal">
reload
</code>
.
</p>
<p>
The
<code class="literal">
reload
</code>
command tells the server
to reload the grant tables into memory.
<code class="literal">
flush-privileges
</code>
is a synonym for
<code class="literal">
reload
</code>
. The
<code class="literal">
refresh
</code>
command closes and reopens
the log files and flushes all tables. The other
<code class="literal">
flush-
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
commands perform functions similar to
<code class="literal">
refresh
</code>
, but are more specific and
may be preferable in some instances. For example, if you
want to flush just the log files,
<code class="literal">
flush-logs
</code>
is a better choice than
<code class="literal">
refresh
</code>
.
</p>
</li>
<li class="listitem">
<p>
Use of
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
options that perform
various
<a class="link" href="flush.html" title="15.7.8.3 FLUSH Statement">
<code class="literal">
FLUSH
</code>
</a>
operations:
<a class="link" href="mysqldump.html#option_mysqldump_flush-logs">
<code class="option">
--flush-logs
</code>
</a>
and
<a class="link" href="mysqldump.html#option_mysqldump_source-data">
<code class="option">
--source-data
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Use of the
<a class="link" href="reset-binary-logs-and-gtids.html" title="15.4.1.2 RESET BINARY LOGS AND GTIDS Statement">
<code class="literal">
RESET BINARY LOGS AND
GTIDS
</code>
</a>
and
<a class="link" href="reset-replica.html" title="15.4.2.3 RESET REPLICA Statement">
<code class="literal">
RESET
REPLICA
</code>
</a>
statements.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<a name="priv_replication-client">
</a>
<a class="link" href="privileges-provided.html#priv_replication-client">
<code class="literal">
REPLICATION CLIENT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251606832">
</a>
<a class="indexterm" name="idm46045251605344">
</a>
<p>
Enables use of the
<a class="link" href="show-binary-log-status.html" title="15.7.7.1 SHOW BINARY LOG STATUS Statement">
<code class="literal">
SHOW BINARY LOG
STATUS
</code>
</a>
,
<a class="link" href="show-replica-status.html" title="15.7.7.35 SHOW REPLICA STATUS Statement">
<code class="literal">
SHOW REPLICA
STATUS
</code>
</a>
, and
<a class="link" href="show-binary-logs.html" title="15.7.7.2 SHOW BINARY LOGS Statement">
<code class="literal">
SHOW BINARY
LOGS
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_replication-slave">
</a>
<a class="link" href="privileges-provided.html#priv_replication-slave">
<code class="literal">
REPLICATION SLAVE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251597712">
</a>
<a class="indexterm" name="idm46045251596224">
</a>
<p>
Enables the account to request updates that have been made
to databases on the replication source server, using the
<a class="link" href="show-replicas.html" title="15.7.7.36 SHOW REPLICAS Statement">
<code class="literal">
SHOW
REPLICAS
</code>
</a>
,
<a class="link" href="show-relaylog-events.html" title="15.7.7.34 SHOW RELAYLOG EVENTS Statement">
<code class="literal">
SHOW RELAYLOG
EVENTS
</code>
</a>
, and
<a class="link" href="show-binlog-events.html" title="15.7.7.3 SHOW BINLOG EVENTS Statement">
<code class="literal">
SHOW BINLOG
EVENTS
</code>
</a>
statements. This privilege is also required
to use the
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
options
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_read-from-remote-server">
<code class="option">
--read-from-remote-server
</code>
</a>
(
<code class="option">
-R
</code>
) and
<a class="link" href="mysqlbinlog.html#option_mysqlbinlog_read-from-remote-source">
<code class="option">
--read-from-remote-source
</code>
</a>
.
Grant this privilege to accounts that are used by replicas
to connect to the current server as their replication source
server.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_select">
</a>
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251584528">
</a>
<a class="indexterm" name="idm46045251583040">
</a>
<p>
Enables rows to be selected from tables in a database.
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statements require the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege only if they
actually access tables. Some
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statements do not
access tables and can be executed without permission for any
database. For example, you can use
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
as a simple calculator
to evaluate expressions that make no reference to tables:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa4210818"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token number">1</span><span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token function">PI</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">2</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege is also
needed for other statements that read column values. For
example,
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
is needed for
columns referenced on the right hand side of
<em class="replaceable">
<code>
col_name
</code>
</em>
=
<em class="replaceable">
<code>
expr
</code>
</em>
assignment in
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
statements or for columns named in the
<code class="literal">
WHERE
</code>
clause of
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
or
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
statements.
</p>
<p>
The
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege is
needed for tables or views used with
<a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
<code class="literal">
EXPLAIN
</code>
</a>
, including any
underlying tables in view definitions.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_show-databases">
</a>
<a class="link" href="privileges-provided.html#priv_show-databases">
<code class="literal">
SHOW DATABASES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251561584">
</a>
<a class="indexterm" name="idm46045251560096">
</a>
<p>
Enables the account to see database names by issuing the
<code class="literal">
SHOW DATABASE
</code>
statement. Accounts that do
not have this privilege see only databases for which they
have some privileges, and cannot use the statement at all if
the server was started with the
<a class="link" href="server-options.html#option_mysqld_skip-show-database">
<code class="option">
--skip-show-database
</code>
</a>
option.
</p>
<div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Caution
</div>
<p>
Because any static global privilege is considered a
privilege for all databases, any static global privilege
enables a user to see all database names with
<a class="link" href="show-databases.html" title="15.7.7.15 SHOW DATABASES Statement">
<code class="literal">
SHOW DATABASES
</code>
</a>
or by
examining the
<a class="link" href="information-schema-schemata-table.html" title="28.3.31 The INFORMATION_SCHEMA SCHEMATA Table">
<code class="literal">
SCHEMATA
</code>
</a>
table
of
<code class="literal">
INFORMATION_SCHEMA
</code>
, except databases
that have been restricted at the database level by partial
revokes.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="priv_show-view">
</a>
<a class="link" href="privileges-provided.html#priv_show-view">
<code class="literal">
SHOW VIEW
</code>
</a>
</p>
<a class="indexterm" name="idm46045251549920">
</a>
<a class="indexterm" name="idm46045251548432">
</a>
<p>
Enables use of the
<a class="link" href="show-create-view.html" title="15.7.7.14 SHOW CREATE VIEW Statement">
<code class="literal">
SHOW CREATE
VIEW
</code>
</a>
statement. This privilege is also needed for
views used with
<a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
<code class="literal">
EXPLAIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_shutdown">
</a>
<a class="link" href="privileges-provided.html#priv_shutdown">
<code class="literal">
SHUTDOWN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251541984">
</a>
<a class="indexterm" name="idm46045251540496">
</a>
<p>
Enables use of the
<a class="link" href="shutdown.html" title="15.7.8.9 SHUTDOWN Statement">
<code class="literal">
SHUTDOWN
</code>
</a>
and
<a class="link" href="restart.html" title="15.7.8.8 RESTART Statement">
<code class="literal">
RESTART
</code>
</a>
statements, the
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin shutdown
</strong>
</span>
</a>
command, and the
<a class="ulink" href="/doc/c-api/8.4/en/mysql-shutdown.html" target="_top">
<code class="literal">
mysql_shutdown()
</code>
</a>
C API
function.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_super">
</a>
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251531680">
</a>
<a class="indexterm" name="idm46045251530192">
</a>
<p>
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
is a powerful and
far-reaching privilege and should not be granted lightly. If
an account needs to perform only a subset of
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
operations, it may be
possible to achieve the desired privilege set by instead
granting one or more dynamic privileges, each of which
confers more limited capabilities. See
<a class="xref" href="privileges-provided.html#privileges-provided-dynamic" title="Dynamic Privilege Descriptions">
Dynamic Privilege Descriptions
</a>
.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
is deprecated, and
you should expect it to be removed in a future version of
MySQL. See
<a class="xref" href="privileges-provided.html#dynamic-privileges-migration-from-super" title="Migrating Accounts from SUPER to Dynamic Privileges">
Migrating Accounts from SUPER to Dynamic Privileges
</a>
.
</p>
</div>
<p>
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
affects the following
operations and server behaviors:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Enables system variable changes at runtime:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: square; ">
<li class="listitem">
<p>
Enables server configuration changes to global
system variables with
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
GLOBAL
</code>
</a>
and
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables setting restricted session system variables
that require a special privilege.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
See also
<a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
Section 7.1.9.1, “System Variable Privileges”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables changes to global transaction characteristics
(see
<a class="xref" href="set-transaction.html" title="15.3.7 SET TRANSACTION Statement">
Section 15.3.7, “SET TRANSACTION Statement”
</a>
).
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables the account to start and stop replication,
including Group Replication.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
for regular replication,
<a class="link" href="privileges-provided.html#priv_group-replication-admin">
<code class="literal">
GROUP_REPLICATION_ADMIN
</code>
</a>
for Group Replication.
</p>
</li>
<li class="listitem">
<p>
Enables use of
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION
SOURCE TO
</code>
</a>
and
<a class="link" href="change-replication-filter.html" title="15.4.2.1 CHANGE REPLICATION FILTER Statement">
<code class="literal">
CHANGE
REPLICATION FILTER
</code>
</a>
statements.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables binary log control by means of the
<a class="link" href="purge-binary-logs.html" title="15.4.1.1 PURGE BINARY LOGS Statement">
<code class="literal">
PURGE BINARY LOGS
</code>
</a>
and
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_binlog-admin">
<code class="literal">
BINLOG_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables setting the effective authorization ID when
executing a view or stored program. A user with this
privilege can specify any account in the
<code class="literal">
DEFINER
</code>
attribute of a view or stored
program.
</p>
<p>
The corresponding dynamic privileges are
<a class="link" href="privileges-provided.html#priv_set-any-definer">
<code class="literal">
SET_ANY_DEFINER
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_allow-nonexistent-definer">
<code class="literal">
ALLOW_NONEXISTENT_DEFINER
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables use of the
<a class="link" href="create-server.html" title="15.1.18 CREATE SERVER Statement">
<code class="literal">
CREATE
SERVER
</code>
</a>
,
<a class="link" href="alter-server.html" title="15.1.8 ALTER SERVER Statement">
<code class="literal">
ALTER
SERVER
</code>
</a>
, and
<a class="link" href="drop-server.html" title="15.1.30 DROP SERVER Statement">
<code class="literal">
DROP
SERVER
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
Enables use of the
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin debug
</strong>
</span>
</a>
command.
</p>
</li>
<li class="listitem">
<p>
Enables
<code class="literal">
InnoDB
</code>
encryption key
rotation.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_encryption-key-admin">
<code class="literal">
ENCRYPTION_KEY_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables execution of Version Tokens functions.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_version-token-admin">
<code class="literal">
VERSION_TOKEN_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables granting and revoking roles, use of the
<code class="literal">
WITH ADMIN OPTION
</code>
clause of the
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement, and
nonempty
<code class="literal">
<graphml>
</code>
element
content in the result from the
<a class="link" href="information-functions.html#function_roles-graphml">
<code class="literal">
ROLES_GRAPHML()
</code>
</a>
function.
</p>
<p>
The corresponding dynamic privilege is
<a class="link" href="privileges-provided.html#priv_role-admin">
<code class="literal">
ROLE_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables control over client connections not permitted to
non-
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
accounts:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: square; ">
<li class="listitem">
<p>
Enables use of the
<a class="link" href="kill.html" title="15.7.8.4 KILL Statement">
<code class="literal">
KILL
</code>
</a>
statement or
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin kill
</strong>
</span>
</a>
command to kill
threads belonging to other accounts. (An account can
always kill its own threads.)
</p>
</li>
<li class="listitem">
<p>
The server does not execute
<a class="link" href="server-system-variables.html#sysvar_init_connect">
<code class="literal">
init_connect
</code>
</a>
system
variable content when
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
clients
connect.
</p>
</li>
<li class="listitem">
<p>
The server accepts one connection from a
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
client even if
the connection limit configured by the
<a class="link" href="server-system-variables.html#sysvar_max_connections">
<code class="literal">
max_connections
</code>
</a>
system variable is reached.
</p>
</li>
<li class="listitem">
<p>
A server in offline mode
(
<a class="link" href="server-system-variables.html#sysvar_offline_mode">
<code class="literal">
offline_mode
</code>
</a>
enabled) does not terminate
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
client
connections at the next client request, and accepts
new connections from
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
clients.
</p>
</li>
<li class="listitem">
<p>
Updates can be performed even when the
<a class="link" href="server-system-variables.html#sysvar_read_only">
<code class="literal">
read_only
</code>
</a>
system
variable is enabled. This applies to explicit table
updates, and to use of account-management statements
such as
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
that update
tables implicitly.
</p>
</li>
</ul>
</div>
<p>
The corresponding dynamic privilege for the preceding
connection-control operations is
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
You may also need the
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege to create or alter stored functions if binary
logging is enabled, as described in
<a class="xref" href="stored-programs-logging.html" title="27.7 Stored Program Binary Logging">
Section 27.7, “Stored Program Binary Logging”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_trigger">
</a>
<a class="link" href="privileges-provided.html#priv_trigger">
<code class="literal">
TRIGGER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251437248">
</a>
<a class="indexterm" name="idm46045251435760">
</a>
<p>
Enables trigger operations. You must have this privilege for
a table to create, drop, execute, or display triggers for
that table.
</p>
<p>
When a trigger is activated (by a user who has privileges to
execute
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, or
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
statements for the
table associated with the trigger), trigger execution
requires that the user who defined the trigger still have
the
<a class="link" href="privileges-provided.html#priv_trigger">
<code class="literal">
TRIGGER
</code>
</a>
privilege for the
table.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_update">
</a>
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251426096">
</a>
<a class="indexterm" name="idm46045251424608">
</a>
<p>
Enables rows to be updated in tables in a database.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_usage">
</a>
<a class="link" href="privileges-provided.html#priv_usage">
<code class="literal">
USAGE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251420656">
</a>
<a class="indexterm" name="idm46045251419168">
</a>
<p>
This privilege specifier stands for
<span class="quote">
“
<span class="quote">
no
privileges.
</span>
”
</span>
It is used at the global level with
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
to specify clauses such
as
<code class="literal">
WITH GRANT OPTION
</code>
without naming
specific account privileges in the privilege list.
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
displays
<a class="link" href="privileges-provided.html#priv_usage">
<code class="literal">
USAGE
</code>
</a>
to indicate that an
account has no privileges at a privilege level.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="privileges-provided-dynamic">
</a>
Dynamic Privilege Descriptions
</h4>
</div>
</div>
</div>
<p>
Dynamic privileges are defined at runtime, in contrast to static
privileges, which are built in to the server. The following list
describes each dynamic privilege available in MySQL.
</p>
<p>
Most dynamic privileges are defined at server startup. Others
are defined by a particular component or plugin, as indicated in
the privilege descriptions. In such cases, the privilege is
unavailable unless the component or plugin that defines it is
enabled.
</p>
<p>
Particular SQL statements might have more specific privilege
requirements than indicated here. If so, the description for the
statement in question provides the details.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="priv_allow-nonexistent-definer">
</a>
<a class="link" href="privileges-provided.html#priv_allow-nonexistent-definer">
<code class="literal">
ALLOW_NONEXISTENT_DEFINER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251406544">
</a>
<a class="indexterm" name="idm46045251405040">
</a>
<p>
Enables overriding security checks designed to prevent
operations that (perhaps inadvertently) cause stored objects
to become orphaned or that cause adoption of stored objects
that are currently orphaned. Without this privilege, any
attempt to produce an orphaned SQL procedure, function, or
view results in an error. An attempt to produce orphaned
objects using
<a class="link" href="create-procedure.html" title="15.1.17 CREATE PROCEDURE and CREATE FUNCTION Statements">
<code class="literal">
CREATE
PROCEDURE
</code>
</a>
,
<a class="link" href="create-function.html" title="15.1.14 CREATE FUNCTION Statement">
<code class="literal">
CREATE
FUNCTION
</code>
</a>
,
<a class="link" href="create-trigger.html" title="15.1.22 CREATE TRIGGER Statement">
<code class="literal">
CREATE
TRIGGER
</code>
</a>
,
<a class="link" href="create-event.html" title="15.1.13 CREATE EVENT Statement">
<code class="literal">
CREATE
EVENT
</code>
</a>
, or
<a class="link" href="create-view.html" title="15.1.23 CREATE VIEW Statement">
<code class="literal">
CREATE
VIEW
</code>
</a>
also requires
<a class="link" href="privileges-provided.html#priv_set-any-definer">
<code class="literal">
SET_ANY_DEFINER
</code>
</a>
in addition
to
<a class="link" href="privileges-provided.html#priv_allow-nonexistent-definer">
<code class="literal">
ALLOW_NONEXISTENT_DEFINER
</code>
</a>
,
so that a definer different from the current user is
permissible.
</p>
<p>
For details, see
<a class="xref" href="stored-objects-security.html#stored-objects-security-orphan-objects" title="Orphan Stored Objects">
Orphan Stored Objects
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_application-password-admin">
</a>
<a class="link" href="privileges-provided.html#priv_application-password-admin">
<code class="literal">
APPLICATION_PASSWORD_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251390544">
</a>
<a class="indexterm" name="idm46045251389040">
</a>
<p>
For dual-password capability, this privilege enables use of
the
<code class="literal">
RETAIN CURRENT PASSWORD
</code>
and
<code class="literal">
DISCARD OLD PASSWORD
</code>
clauses for
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
</code>
</a>
and
<a class="link" href="set-password.html" title="15.7.1.10 SET PASSWORD Statement">
<code class="literal">
SET PASSWORD
</code>
</a>
statements that
apply to your own account. This privilege is required to
manipulate your own secondary password because most users
require only one password.
</p>
<p>
If an account is to be permitted to manipulate secondary
passwords for all accounts, it should be granted the
<a class="link" href="privileges-provided.html#priv_create-user">
<code class="literal">
CREATE USER
</code>
</a>
privilege rather
than
<a class="link" href="privileges-provided.html#priv_application-password-admin">
<code class="literal">
APPLICATION_PASSWORD_ADMIN
</code>
</a>
.
</p>
<p>
For more information about use of dual passwords, see
<a class="xref" href="password-management.html" title="8.2.15 Password Management">
Section 8.2.15, “Password Management”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_audit-abort-exempt">
</a>
<a class="link" href="privileges-provided.html#priv_audit-abort-exempt">
<code class="literal">
AUDIT_ABORT_EXEMPT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251376704">
</a>
<a class="indexterm" name="idm46045251375216">
</a>
<p>
Allows queries blocked by an
<span class="quote">
“
<span class="quote">
abort
</span>
”
</span>
item in
the audit log filter. This privilege is defined by the
<code class="literal">
audit_log
</code>
plugin; see
<a class="xref" href="audit-log.html" title="8.4.5 MySQL Enterprise Audit">
Section 8.4.5, “MySQL Enterprise Audit”
</a>
.
</p>
<p>
Accounts created with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege have
the
<a class="link" href="privileges-provided.html#priv_audit-abort-exempt">
<code class="literal">
AUDIT_ABORT_EXEMPT
</code>
</a>
privilege assigned automatically when they are created. The
<a class="link" href="privileges-provided.html#priv_audit-abort-exempt">
<code class="literal">
AUDIT_ABORT_EXEMPT
</code>
</a>
privilege
is also assigned to existing accounts with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege when you carry out an upgrade procedure, if no
existing accounts have that privilege assigned. Accounts
with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege can therefore be used to regain access to a system
following an audit misconfiguration.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_audit-admin">
</a>
<a class="link" href="privileges-provided.html#priv_audit-admin">
<code class="literal">
AUDIT_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251362400">
</a>
<a class="indexterm" name="idm46045251360912">
</a>
<p>
Enables audit log configuration. This privilege is defined
by the
<code class="literal">
audit_log
</code>
plugin; see
<a class="xref" href="audit-log.html" title="8.4.5 MySQL Enterprise Audit">
Section 8.4.5, “MySQL Enterprise Audit”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_backup-admin">
</a>
<a class="link" href="privileges-provided.html#priv_backup-admin">
<code class="literal">
BACKUP_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251355600">
</a>
<a class="indexterm" name="idm46045251354112">
</a>
<p>
Enables execution of the
<a class="link" href="lock-instance-for-backup.html" title="15.3.5 LOCK INSTANCE FOR BACKUP and UNLOCK INSTANCE Statements">
<code class="literal">
LOCK INSTANCE
FOR BACKUP
</code>
</a>
statement and access to the Performance
Schema
<a class="link" href="performance-schema-log-status-table.html" title="29.12.22.5 The log_status Table">
<code class="literal">
log_status
</code>
</a>
table.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Besides
<a class="link" href="privileges-provided.html#priv_backup-admin">
<code class="literal">
BACKUP_ADMIN
</code>
</a>
, the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege on the
<a class="link" href="performance-schema-log-status-table.html" title="29.12.22.5 The log_status Table">
<code class="literal">
log_status
</code>
</a>
table is also
needed for its access.
</p>
</div>
<p>
The
<a class="link" href="privileges-provided.html#priv_backup-admin">
<code class="literal">
BACKUP_ADMIN
</code>
</a>
privilege is
automatically granted to users with the
<a class="link" href="privileges-provided.html#priv_reload">
<code class="literal">
RELOAD
</code>
</a>
privilege when
performing an in-place upgrade to MySQL 8.4
from an earlier version.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_authentication-policy-admin">
</a>
<a class="link" href="privileges-provided.html#priv_authentication-policy-admin">
<code class="literal">
AUTHENTICATION_POLICY_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251339728">
</a>
<a class="indexterm" name="idm46045251338224">
</a>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
system variable places certain constraints on how the
authentication-related clauses of
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
and
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
</code>
</a>
statements may be
used. A user who has the
<a class="link" href="privileges-provided.html#priv_authentication-policy-admin">
<code class="literal">
AUTHENTICATION_POLICY_ADMIN
</code>
</a>
privilege is not subject to these constraints. (A warning
does occur for statements that otherwise would not be
permitted.)
</p>
<p>
For details about the constraints imposed by
<a class="link" href="server-system-variables.html#sysvar_authentication_policy">
<code class="literal">
authentication_policy
</code>
</a>
, see
the description of that variable.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_binlog-admin">
</a>
<a class="link" href="privileges-provided.html#priv_binlog-admin">
<code class="literal">
BINLOG_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251327216">
</a>
<a class="indexterm" name="idm46045251325728">
</a>
<p>
Enables binary log control by means of the
<a class="link" href="purge-binary-logs.html" title="15.4.1.1 PURGE BINARY LOGS Statement">
<code class="literal">
PURGE BINARY LOGS
</code>
</a>
and
<a class="link" href="binlog.html" title="15.7.8.1 BINLOG Statement">
<code class="literal">
BINLOG
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_binlog-encryption-admin">
</a>
<a class="link" href="privileges-provided.html#priv_binlog-encryption-admin">
<code class="literal">
BINLOG_ENCRYPTION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251319216">
</a>
<a class="indexterm" name="idm46045251317728">
</a>
<p>
Enables setting the system variable
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_encryption">
<code class="literal">
binlog_encryption
</code>
</a>
, which
activates or deactivates encryption for binary log files and
relay log files. This ability is not provided by the
<a class="link" href="privileges-provided.html#priv_binlog-admin">
<code class="literal">
BINLOG_ADMIN
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
, or
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
privileges. The related system variable
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_rotate_encryption_master_key_at_startup">
<code class="literal">
binlog_rotate_encryption_master_key_at_startup
</code>
</a>
,
which rotates the binary log master key automatically when
the server is restarted, does not require this privilege.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_clone-admin">
</a>
<a class="link" href="privileges-provided.html#priv_clone-admin">
<code class="literal">
CLONE_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251307200">
</a>
<a class="indexterm" name="idm46045251305712">
</a>
<p>
Enables execution of the
<code class="literal">
CLONE
</code>
statements. Includes
<a class="link" href="privileges-provided.html#priv_backup-admin">
<code class="literal">
BACKUP_ADMIN
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_shutdown">
<code class="literal">
SHUTDOWN
</code>
</a>
privileges.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_connection-admin">
</a>
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251298592">
</a>
<a class="indexterm" name="idm46045251297104">
</a>
<p>
Enables use of the
<a class="link" href="kill.html" title="15.7.8.4 KILL Statement">
<code class="literal">
KILL
</code>
</a>
statement or
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin kill
</strong>
</span>
</a>
command to
kill threads belonging to other accounts. (An account can
always kill its own threads.)
</p>
<p>
Enables setting system variables related to client
connections, or circumventing restrictions related to client
connections.
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
is required to activate MySQL Server’s offline mode, which
is done by changing the value of the
<a class="link" href="server-system-variables.html#sysvar_offline_mode">
<code class="literal">
offline_mode
</code>
</a>
system
variable to
<code class="literal">
ON
</code>
.
</p>
<p>
The
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
privilege enables administrators with it to bypass effects
of these system variables:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_init_connect">
<code class="literal">
init_connect
</code>
</a>
: The
server does not execute
<a class="link" href="server-system-variables.html#sysvar_init_connect">
<code class="literal">
init_connect
</code>
</a>
system
variable content when
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
clients
connect.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_max_connections">
<code class="literal">
max_connections
</code>
</a>
: The
server accepts one connection from a
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
client
even if the connection limit configured by the
<a class="link" href="server-system-variables.html#sysvar_max_connections">
<code class="literal">
max_connections
</code>
</a>
system
variable is reached.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_offline_mode">
<code class="literal">
offline_mode
</code>
</a>
: A server
in offline mode
(
<a class="link" href="server-system-variables.html#sysvar_offline_mode">
<code class="literal">
offline_mode
</code>
</a>
enabled)
does not terminate
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
client
connections at the next client request, and accepts new
connections from
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
clients.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_read_only">
<code class="literal">
read_only
</code>
</a>
: Updates from
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
clients
can be performed even when the
<a class="link" href="server-system-variables.html#sysvar_read_only">
<code class="literal">
read_only
</code>
</a>
system
variable is enabled. This applies to explicit table
updates, and to account management statements such as
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
that update tables
implicitly.
</p>
</li>
</ul>
</div>
<p>
Group Replication group members need the
<a class="link" href="privileges-provided.html#priv_connection-admin">
<code class="literal">
CONNECTION_ADMIN
</code>
</a>
privilege so
that Group Replication connections are not terminated if one
of the servers involved is placed in offline mode. If the
MySQL communication stack is in use
(
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_communication_stack">
<code class="literal">
group_replication_communication_stack
= MYSQL
</code>
</a>
), without this privilege, a member that is
placed in offline mode is expelled from the group.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_encryption-key-admin">
</a>
<a class="link" href="privileges-provided.html#priv_encryption-key-admin">
<code class="literal">
ENCRYPTION_KEY_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251255968">
</a>
<a class="indexterm" name="idm46045251254480">
</a>
<p>
Enables
<code class="literal">
InnoDB
</code>
encryption key rotation.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_firewall-admin">
</a>
<a class="link" href="privileges-provided.html#priv_firewall-admin">
<code class="literal">
FIREWALL_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251249888">
</a>
<a class="indexterm" name="idm46045251248400">
</a>
<p>
Enables a user to administer firewall rules for any user.
This privilege is defined by the
<code class="literal">
MYSQL_FIREWALL
</code>
plugin; see
<a class="xref" href="firewall.html" title="8.4.7 MySQL Enterprise Firewall">
Section 8.4.7, “MySQL Enterprise Firewall”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_firewall-exempt">
</a>
<a class="link" href="privileges-provided.html#priv_firewall-exempt">
<code class="literal">
FIREWALL_EXEMPT
</code>
</a>
</p>
<a class="indexterm" name="idm46045251242976">
</a>
<a class="indexterm" name="idm46045251241488">
</a>
<p>
A user with this privilege is exempt from firewall
restrictions. This privilege is defined by the
<code class="literal">
MYSQL_FIREWALL
</code>
plugin; see
<a class="xref" href="firewall.html" title="8.4.7 MySQL Enterprise Firewall">
Section 8.4.7, “MySQL Enterprise Firewall”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_firewall-user">
</a>
<a class="link" href="privileges-provided.html#priv_firewall-user">
<code class="literal">
FIREWALL_USER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251236128">
</a>
<a class="indexterm" name="idm46045251234640">
</a>
<p>
Enables users to update their own firewall rules. This
privilege is defined by the
<code class="literal">
MYSQL_FIREWALL
</code>
plugin; see
<a class="xref" href="firewall.html" title="8.4.7 MySQL Enterprise Firewall">
Section 8.4.7, “MySQL Enterprise Firewall”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_flush-optimizer-costs">
</a>
<a class="link" href="privileges-provided.html#priv_flush-optimizer-costs">
<code class="literal">
FLUSH_OPTIMIZER_COSTS
</code>
</a>
</p>
<a class="indexterm" name="idm46045251229184">
</a>
<a class="indexterm" name="idm46045251227696">
</a>
<p>
Enables use of the
<a class="link" href="flush.html#flush-optimizer-costs">
<code class="literal">
FLUSH
OPTIMIZER_COSTS
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_flush-privileges">
</a>
<a class="link" href="privileges-provided.html#priv_flush-privileges">
<code class="literal">
FLUSH_PRIVILEGES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251222464">
</a>
<a class="indexterm" name="idm46045251220976">
</a>
<p>
Enables use of the
<a class="link" href="flush.html#flush-privileges">
<code class="literal">
FLUSH
PRIVILEGES
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_flush-status">
</a>
<a class="link" href="privileges-provided.html#priv_flush-status">
<code class="literal">
FLUSH_STATUS
</code>
</a>
</p>
<a class="indexterm" name="idm46045251215808">
</a>
<a class="indexterm" name="idm46045251214320">
</a>
<p>
Enables use of the
<a class="link" href="flush.html#flush-status">
<code class="literal">
FLUSH
STATUS
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_flush-tables">
</a>
<a class="link" href="privileges-provided.html#priv_flush-tables">
<code class="literal">
FLUSH_TABLES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251209168">
</a>
<a class="indexterm" name="idm46045251207680">
</a>
<p>
Enables use of the
<a class="link" href="flush.html#flush-tables">
<code class="literal">
FLUSH
TABLES
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_flush-user-resources">
</a>
<a class="link" href="privileges-provided.html#priv_flush-user-resources">
<code class="literal">
FLUSH_USER_RESOURCES
</code>
</a>
</p>
<a class="indexterm" name="idm46045251202416">
</a>
<a class="indexterm" name="idm46045251200928">
</a>
<p>
Enables use of the
<a class="link" href="flush.html#flush-user-resources">
<code class="literal">
FLUSH
USER_RESOURCES
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_group-replication-admin">
</a>
<a class="link" href="privileges-provided.html#priv_group-replication-admin">
<code class="literal">
GROUP_REPLICATION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251195568">
</a>
<a class="indexterm" name="idm46045251194080">
</a>
<p>
Enables the account to start and stop Group Replication
using the
<a class="link" href="start-group-replication.html" title="15.4.3.1 START GROUP_REPLICATION Statement">
<code class="literal">
START GROUP
REPLICATION
</code>
</a>
and
<a class="link" href="stop-group-replication.html" title="15.4.3.2 STOP GROUP_REPLICATION Statement">
<code class="literal">
STOP GROUP
REPLICATION
</code>
</a>
statements, to change the global
setting for the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_consistency">
<code class="literal">
group_replication_consistency
</code>
</a>
system variable, and to use the
<a class="link" href="group-replication-functions-for-maximum-consensus.html#function_group-replication-set-write-concurrency">
<code class="literal">
group_replication_set_write_concurrency()
</code>
</a>
and
<a class="link" href="group-replication-functions-for-communication-protocol.html#function_group-replication-set-communication-protocol">
<code class="literal">
group_replication_set_communication_protocol()
</code>
</a>
functions. Grant this privilege to accounts that are used to
administer servers that are members of a replication group.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_group-replication-stream">
</a>
<a class="link" href="privileges-provided.html#priv_group-replication-stream">
<code class="literal">
GROUP_REPLICATION_STREAM
</code>
</a>
</p>
<a class="indexterm" name="idm46045251182960">
</a>
<a class="indexterm" name="idm46045251181456">
</a>
<p>
Allows a user account to be used for establishing Group
Replication's group communication connections. It must be
granted to a recovery user when the MySQL communication
stack is used for Group Replication
(
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_communication_stack">
<code class="literal">
group_replication_communication_stack=MYSQL
</code>
</a>
).
</p>
</li>
<li class="listitem">
<p>
<a name="priv_innodb-redo-log-archive">
</a>
<a class="link" href="privileges-provided.html#priv_innodb-redo-log-archive">
<code class="literal">
INNODB_REDO_LOG_ARCHIVE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251175856">
</a>
<a class="indexterm" name="idm46045251174368">
</a>
<p>
Enables the account to activate and deactivate redo log
archiving.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_innodb-redo-log-enable">
</a>
<a class="link" href="privileges-provided.html#priv_innodb-redo-log-enable">
<code class="literal">
INNODB_REDO_LOG_ENABLE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251170384">
</a>
<a class="indexterm" name="idm46045251168896">
</a>
<p>
Enables use of the
<a class="link" href="alter-instance.html" title="15.1.5 ALTER INSTANCE Statement">
<code class="literal">
ALTER
INSTANCE {ENABLE|DISABLE} INNODB REDO_LOG
</code>
</a>
statement to enable or disable redo logging.
</p>
<p>
See
<a class="xref" href="innodb-redo-log.html#innodb-disable-redo-logging" title="Disabling Redo Logging">
Disabling Redo Logging
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_masking-dictionaries-admin">
</a>
<a class="link" href="privileges-provided.html#priv_masking-dictionaries-admin">
<code class="literal">
MASKING_DICTIONARIES_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251162480">
</a>
<a class="indexterm" name="idm46045251160976">
</a>
<p>
Enables the account to add and remove dictionary terms using
the
<a class="link" href="data-masking-component-functions.html#function_masking-dictionary-term-add">
<code class="literal">
masking_dictionary_term_add()
</code>
</a>
and
<a class="link" href="data-masking-component-functions.html#function_masking-dictionary-term-remove">
<code class="literal">
masking_dictionary_term_remove()
</code>
</a>
component functions. Accounts also require this dynamic
privilege to remove a full dictionary using the
<a class="link" href="data-masking-component-functions.html#function_masking-dictionary-remove">
<code class="literal">
masking_dictionary_remove()
</code>
</a>
function, which removes all of the terms associated with the
named dictionary currently in the
<code class="literal">
mysql.masking_dictionaries
</code>
table.
</p>
<p>
See
<a class="xref" href="data-masking.html" title="8.5 MySQL Enterprise Data Masking and De-Identification">
Section 8.5, “MySQL Enterprise Data Masking and De-Identification”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_ndb-stored-user">
</a>
<a class="link" href="privileges-provided.html#priv_ndb-stored-user">
<code class="literal">
NDB_STORED_USER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251150592">
</a>
<a class="indexterm" name="idm46045251149104">
</a>
<p>
Enables the user or role and its privileges to be shared and
synchronized between all
<code class="literal">
NDB
</code>
-enabled
MySQL servers as soon as they join a given NDB Cluster. This
privilege is available only if the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
storage engine is enabled.
</p>
<p>
Any changes to or revocations of privileges made for the
given user or role are synchronized immediately with all
connected MySQL servers (SQL nodes). You should be aware
that there is no guarantee that multiple statements
affecting privileges originating from different SQL nodes
are executed on all SQL nodes in the same order. For this
reason, it is highly recommended that all user
administration be done from a single designated SQL node.
</p>
<p>
<code class="literal">
NDB_STORED_USER
</code>
is a global privilege and
must be granted or revoked using
<code class="literal">
ON *.*
</code>
.
Trying to set any other scope for this privilege results in
an error. This privilege can be given to most application
and administrative users, but it cannot be granted to system
reserved accounts such as
<code class="literal">
mysql.session@localhost
</code>
or
<code class="literal">
mysql.infoschema@localhost
</code>
.
</p>
<p>
A user that has been granted the
<code class="literal">
NDB_STORED_USER
</code>
privilege is stored in
<code class="literal">
NDB
</code>
(and thus shared by all SQL nodes),
as is a role with this privilege. A user that is merely
granted a role that has
<code class="literal">
NDB_STORED_USER
</code>
is
<span class="emphasis">
<em>
not
</em>
</span>
stored in
<code class="literal">
NDB
</code>
; each
<code class="literal">
NDB
</code>
stored
user must be granted the privilege explicitly.
</p>
<p>
For more detailed information about how this works in
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
, see
<a class="xref" href="mysql-cluster-privilege-synchronization.html" title="25.6.13 Privilege Synchronization and NDB_STORED_USER">
Section 25.6.13, “Privilege Synchronization and NDB_STORED_USER”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_optimize-local-table">
</a>
<a class="link" href="privileges-provided.html#priv_optimize-local-table">
<code class="literal">
OPTIMIZE_LOCAL_TABLE
</code>
</a>
</p>
<a class="indexterm" name="idm46045251131280">
</a>
<a class="indexterm" name="idm46045251129792">
</a>
<p>
Enables use of
<a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
<code class="literal">
OPTIMIZE
LOCAL TABLE
</code>
</a>
and
<a class="link" href="optimize-table.html" title="15.7.3.4 OPTIMIZE TABLE Statement">
<code class="literal">
OPTIMIZE
NO_WRITE_TO_BINLOG TABLE
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_passwordless-user-admin">
</a>
<a class="link" href="privileges-provided.html#priv_passwordless-user-admin">
<code class="literal">
PASSWORDLESS_USER_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251123280">
</a>
<a class="indexterm" name="idm46045251121792">
</a>
<p>
This privilege applies to passwordless user accounts:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
For account creation, a user who executes
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
to create a
passwordless account must possess the
<a class="link" href="privileges-provided.html#priv_passwordless-user-admin">
<code class="literal">
PASSWORDLESS_USER_ADMIN
</code>
</a>
privilege.
</p>
</li>
<li class="listitem">
<p>
In replication context, the
<a class="link" href="privileges-provided.html#priv_passwordless-user-admin">
<code class="literal">
PASSWORDLESS_USER_ADMIN
</code>
</a>
privilege applies to replication users and enables
replication of
<a class="link" href="alter-user.html" title="15.7.1.1 ALTER USER Statement">
<code class="literal">
ALTER USER
... MODIFY
</code>
</a>
statements for user accounts that
are configured for passwordless authentication.
</p>
</li>
</ul>
</div>
<p>
For information about passwordless authentication, see
<a class="xref" href="webauthn-pluggable-authentication.html#webauthn-pluggable-authentication-passwordless" title="WebAuthn Passwordless Authentication">
WebAuthn Passwordless Authentication
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_persist-ro-variables-admin">
</a>
<a class="link" href="privileges-provided.html#priv_persist-ro-variables-admin">
<code class="literal">
PERSIST_RO_VARIABLES_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251109072">
</a>
<a class="indexterm" name="idm46045251107568">
</a>
<p>
For users who also have
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_persist-ro-variables-admin">
<code class="literal">
PERSIST_RO_VARIABLES_ADMIN
</code>
</a>
enables use of
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
to persist global system variables to
the
<code class="filename">
mysqld-auto.cnf
</code>
option file in the
data directory. This statement is similar to
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
but does not modify the runtime global
system variable value. This makes
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
suitable for configuring read-only
system variables that can be set only at server startup.
</p>
<p>
See also
<a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
Section 7.1.9.1, “System Variable Privileges”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_replication-applier">
</a>
<a class="link" href="privileges-provided.html#priv_replication-applier">
<code class="literal">
REPLICATION_APPLIER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251095088">
</a>
<a class="indexterm" name="idm46045251093600">
</a>
<p>
Enables the account to act as the
<code class="literal">
PRIVILEGE_CHECKS_USER
</code>
for a replication
channel, and to execute
<code class="literal">
BINLOG
</code>
statements
in
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
output. Grant this
privilege to accounts that are assigned using
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE TO
</code>
</a>
to provide a security context for replication channels, and
to handle replication errors on those channels. As well as
the
<code class="literal">
REPLICATION_APPLIER
</code>
privilege, you
must also give the account the required privileges to
execute the transactions received by the replication channel
or contained in the
<a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
<span class="command">
<strong>
mysqlbinlog
</strong>
</span>
</a>
output,
for example to update the affected tables. For more
information, see
<a class="xref" href="replication-privilege-checks.html" title="19.3.3 Replication Privilege Checks">
Section 19.3.3, “Replication Privilege Checks”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_replication-slave-admin">
</a>
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251082496">
</a>
<a class="indexterm" name="idm46045251081008">
</a>
<p>
Enables the account to connect to the replication source
server, start and stop replication using the
<a class="link" href="start-replica.html" title="15.4.2.4 START REPLICA Statement">
<code class="literal">
START REPLICA
</code>
</a>
and
<a class="link" href="stop-replica.html" title="15.4.2.5 STOP REPLICA Statement">
<code class="literal">
STOP REPLICA
</code>
</a>
statements, and
use the
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE
TO
</code>
</a>
and
<a class="link" href="change-replication-filter.html" title="15.4.2.1 CHANGE REPLICATION FILTER Statement">
<code class="literal">
CHANGE REPLICATION
FILTER
</code>
</a>
statements. Grant this privilege to
accounts that are used by replicas to connect to the current
server as their replication source server. This privilege
does not apply to Group Replication; use
<code class="literal">
GROUP_REPLICATION_ADMIN
</code>
for that.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_resource-group-admin">
</a>
<a class="link" href="privileges-provided.html#priv_resource-group-admin">
<code class="literal">
RESOURCE_GROUP_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251070976">
</a>
<a class="indexterm" name="idm46045251069488">
</a>
<p>
Enables resource group management, consisting of creating,
altering, and dropping resource groups, and assignment of
threads and statements to resource groups. A user with this
privilege can perform any operation relating to resource
groups.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_resource-group-user">
</a>
<a class="link" href="privileges-provided.html#priv_resource-group-user">
<code class="literal">
RESOURCE_GROUP_USER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251065216">
</a>
<a class="indexterm" name="idm46045251063728">
</a>
<p>
Enables assigning threads and statements to resource groups.
A user with this privilege can use the
<a class="link" href="set-resource-group.html" title="15.7.2.4 SET RESOURCE GROUP Statement">
<code class="literal">
SET RESOURCE GROUP
</code>
</a>
statement
and the
<a class="link" href="optimizer-hints.html#optimizer-hints-resource-group" title="Resource Group Hint Syntax">
<code class="literal">
RESOURCE_GROUP
</code>
</a>
optimizer hint.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_role-admin">
</a>
<a class="link" href="privileges-provided.html#priv_role-admin">
<code class="literal">
ROLE_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251057280">
</a>
<a class="indexterm" name="idm46045251055792">
</a>
<p>
Enables granting and revoking roles, use of the
<code class="literal">
WITH ADMIN OPTION
</code>
clause of the
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement, and nonempty
<code class="literal">
<graphml>
</code>
element content in the
result from the
<a class="link" href="information-functions.html#function_roles-graphml">
<code class="literal">
ROLES_GRAPHML()
</code>
</a>
function.
Required to set the value of the
<a class="link" href="server-system-variables.html#sysvar_mandatory_roles">
<code class="literal">
mandatory_roles
</code>
</a>
system
variable.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_sensitive-variables-observer">
</a>
<a class="link" href="privileges-provided.html#priv_sensitive-variables-observer">
<code class="literal">
SENSITIVE_VARIABLES_OBSERVER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251046528">
</a>
<a class="indexterm" name="idm46045251045024">
</a>
<p>
Enables a holder to view the values of sensitive system
variables in the Performance Schema tables
<a class="link" href="performance-schema-system-variable-tables.html" title="29.12.14 Performance Schema System Variable Tables">
<code class="literal">
global_variables
</code>
</a>
,
<a class="link" href="performance-schema-system-variable-tables.html" title="29.12.14 Performance Schema System Variable Tables">
<code class="literal">
session_variables
</code>
</a>
,
<a class="link" href="performance-schema-system-variable-tables.html" title="29.12.14 Performance Schema System Variable Tables">
<code class="literal">
variables_by_thread
</code>
</a>
, and
<a class="link" href="performance-schema-persisted-variables-table.html" title="29.12.14.1 Performance Schema persisted_variables Table">
<code class="literal">
persisted_variables
</code>
</a>
, to issue
<code class="literal">
SELECT
</code>
statements to return their values,
and to track changes to them in session trackers for
connections. Users without this privilege cannot view or
track those system variable values. See
<a class="xref" href="persisted-system-variables.html#persisted-system-variables-sensitive" title="Persisting Sensitive System Variables">
Persisting Sensitive System Variables
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_service-connection-admin">
</a>
<a class="link" href="privileges-provided.html#priv_service-connection-admin">
<code class="literal">
SERVICE_CONNECTION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251034080">
</a>
<a class="indexterm" name="idm46045251032576">
</a>
<p>
Enables connections to the network interface that permits
only administrative connections (see
<a class="xref" href="connection-interfaces.html" title="7.1.12.1 Connection Interfaces">
Section 7.1.12.1, “Connection Interfaces”
</a>
).
</p>
</li>
<li class="listitem">
<p>
<a name="priv_session-variables-admin">
</a>
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045251027776">
</a>
<a class="indexterm" name="idm46045251026288">
</a>
<p>
For most system variables, setting the session value
requires no special privileges and can be done by any user
to affect the current session. For some system variables,
setting the session value can have effects outside the
current session and thus is a restricted operation. For
these, the
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
privilege enables the user to set the session value.
</p>
<p>
If a system variable is restricted and requires a special
privilege to set the session value, the variable description
indicates that restriction. Examples include
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
,
<a class="link" href="replication-options-binary-log.html#sysvar_sql_log_bin">
<code class="literal">
sql_log_bin
</code>
</a>
, and
<a class="link" href="server-system-variables.html#sysvar_sql_log_off">
<code class="literal">
sql_log_off
</code>
</a>
.
</p>
<p>
The
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
privilege is a subset of the
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privileges. A user who
has either of those privileges is also permitted to set
restricted session variables and effectively has
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
by
implication and need not be granted
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
explicitly.
</p>
<p>
See also
<a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
Section 7.1.9.1, “System Variable Privileges”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_set-any-definer">
</a>
<a class="link" href="privileges-provided.html#priv_set-any-definer">
<code class="literal">
SET_ANY_DEFINER
</code>
</a>
</p>
<a class="indexterm" name="idm46045251008368">
</a>
<a class="indexterm" name="idm46045251006880">
</a>
<p>
Enables setting the effective authorization ID when
executing a view or stored program. A user with this
privilege can specify any account as the
<code class="literal">
DEFINER
</code>
attribute for
<a class="link" href="create-procedure.html" title="15.1.17 CREATE PROCEDURE and CREATE FUNCTION Statements">
<code class="literal">
CREATE PROCEDURE
</code>
</a>
,
<a class="link" href="create-function.html" title="15.1.14 CREATE FUNCTION Statement">
<code class="literal">
CREATE FUNCTION
</code>
</a>
,
<a class="link" href="create-trigger.html" title="15.1.22 CREATE TRIGGER Statement">
<code class="literal">
CREATE TRIGGER
</code>
</a>
,
<a class="link" href="create-event.html" title="15.1.13 CREATE EVENT Statement">
<code class="literal">
CREATE EVENT
</code>
</a>
,
<a class="link" href="alter-event.html" title="15.1.3 ALTER EVENT Statement">
<code class="literal">
ALTER EVENT
</code>
</a>
,
<a class="link" href="create-view.html" title="15.1.23 CREATE VIEW Statement">
<code class="literal">
CREATE VIEW
</code>
</a>
, and
<a class="link" href="alter-view.html" title="15.1.11 ALTER VIEW Statement">
<code class="literal">
ALTER VIEW
</code>
</a>
. Without this
privilege, only the effective authentication ID can be
specified.
</p>
<p>
Stored programs execute with the privileges of the specified
account, so ensure that you follow the risk minimization
guidelines listed in
<a class="xref" href="stored-objects-security.html" title="27.6 Stored Object Access Control">
Section 27.6, “Stored Object Access Control”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_show-routine">
</a>
<a class="link" href="privileges-provided.html#priv_show-routine">
<code class="literal">
SHOW_ROUTINE
</code>
</a>
</p>
<a class="indexterm" name="idm46045250992080">
</a>
<a class="indexterm" name="idm46045250990592">
</a>
<p>
Enables a user to access definitions and properties of all
stored routines (stored procedures and functions), even
those for which the user is not named as the routine
<code class="literal">
DEFINER
</code>
. This access includes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
The contents of the Information Schema
<a class="link" href="information-schema-routines-table.html" title="28.3.30 The INFORMATION_SCHEMA ROUTINES Table">
<code class="literal">
ROUTINES
</code>
</a>
table.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="show-create-function.html" title="15.7.7.9 SHOW CREATE FUNCTION Statement">
<code class="literal">
SHOW CREATE FUNCTION
</code>
</a>
and
<a class="link" href="show-create-procedure.html" title="15.7.7.10 SHOW CREATE PROCEDURE Statement">
<code class="literal">
SHOW CREATE PROCEDURE
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="show-function-code.html" title="15.7.7.20 SHOW FUNCTION CODE Statement">
<code class="literal">
SHOW FUNCTION CODE
</code>
</a>
and
<a class="link" href="show-procedure-code.html" title="15.7.7.29 SHOW PROCEDURE CODE Statement">
<code class="literal">
SHOW PROCEDURE CODE
</code>
</a>
statements.
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="show-function-status.html" title="15.7.7.21 SHOW FUNCTION STATUS Statement">
<code class="literal">
SHOW FUNCTION STATUS
</code>
</a>
and
<a class="link" href="show-procedure-status.html" title="15.7.7.30 SHOW PROCEDURE STATUS Statement">
<code class="literal">
SHOW PROCEDURE STATUS
</code>
</a>
statements.
</p>
</li>
</ul>
</div>
<p>
<a class="link" href="privileges-provided.html#priv_show-routine">
<code class="literal">
SHOW_ROUTINE
</code>
</a>
may be granted
instead as a privilege with a more restricted scope that
permits access to routine definitions. (That is, an
administrator can rescind global
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
from users that do not
otherwise require it and grant
<a class="link" href="privileges-provided.html#priv_show-routine">
<code class="literal">
SHOW_ROUTINE
</code>
</a>
instead.) This
enables an account to back up stored routines without
requiring a broad privilege.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_skip-query-rewrite">
</a>
<a class="link" href="privileges-provided.html#priv_skip-query-rewrite">
<code class="literal">
SKIP_QUERY_REWRITE
</code>
</a>
</p>
<a class="indexterm" name="idm46045250968032">
</a>
<a class="indexterm" name="idm46045250966544">
</a>
<p>
Queries issued by a user with this privilege are not subject
to being rewritten by the
<code class="literal">
Rewriter
</code>
plugin
(see
<a class="xref" href="rewriter-query-rewrite-plugin.html" title="7.6.4 The Rewriter Query Rewrite Plugin">
Section 7.6.4, “The Rewriter Query Rewrite Plugin”
</a>
).
</p>
<p>
This privilege should be granted to users issuing
administrative or control statements that should not be
rewritten, as well as to
<code class="literal">
PRIVILEGE_CHECKS_USER
</code>
accounts (see
<a class="xref" href="replication-privilege-checks.html" title="19.3.3 Replication Privilege Checks">
Section 19.3.3, “Replication Privilege Checks”
</a>
) used to
apply statements from a replication source.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_system-user">
</a>
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
</p>
<a class="indexterm" name="idm46045250959024">
</a>
<a class="indexterm" name="idm46045250957536">
</a>
<p>
The
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege
distinguishes system users from regular users:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
A user with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege is
a system user.
</p>
</li>
<li class="listitem">
<p>
A user without the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege is
a regular user.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege has
an effect on the accounts to which a given user can apply
its other privileges, as well as whether the user is
protected from other accounts:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
A system user can modify both system and regular
accounts. That is, a user who has the appropriate
privileges to perform a given operation on regular
accounts is enabled by possession of
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
to also
perform the operation on system accounts. A system
account can be modified only by system users with
appropriate privileges, not by regular users.
</p>
</li>
<li class="listitem">
<p>
A regular user with appropriate privileges can modify
regular accounts, but not system accounts. A regular
account can be modified by both system and regular users
with appropriate privileges.
</p>
</li>
</ul>
</div>
<p>
This also means that database objects created by users with
the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege
cannot be modified or dropped by users without the
privilege. This also applies to routines for which the
definer has this privilege.
</p>
<p>
For more information, see
<a class="xref" href="account-categories.html" title="8.2.11 Account Categories">
Section 8.2.11, “Account Categories”
</a>
.
</p>
<p>
The protection against modification by regular accounts that
is afforded to system accounts by the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege does
not apply to regular accounts that have privileges on the
<code class="literal">
mysql
</code>
system schema and thus can directly
modify the grant tables in that schema. For full protection,
do not grant
<code class="literal">
mysql
</code>
schema privileges to
regular accounts. See
<a class="xref" href="account-categories.html#protecting-system-accounts" title="Protecting System Accounts Against Manipulation by Regular Accounts">
Protecting System Accounts Against Manipulation by Regular Accounts
</a>
.
</p>
<p>
If the
<code class="literal">
audit_log
</code>
plugin is in use (see
<a class="xref" href="audit-log.html" title="8.4.5 MySQL Enterprise Audit">
Section 8.4.5, “MySQL Enterprise Audit”
</a>
), accounts with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege are
automatically assigned the
<a class="link" href="privileges-provided.html#priv_audit-abort-exempt">
<code class="literal">
AUDIT_ABORT_EXEMPT
</code>
</a>
privilege,
which permits their queries to be executed even if an
<span class="quote">
“
<span class="quote">
abort
</span>
”
</span>
item configured in the filter would
block them. Accounts with the
<a class="link" href="privileges-provided.html#priv_system-user">
<code class="literal">
SYSTEM_USER
</code>
</a>
privilege can
therefore be used to regain access to a system following an
audit misconfiguration.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_system-variables-admin">
</a>
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250928016">
</a>
<a class="indexterm" name="idm46045250926528">
</a>
<p>
Affects the following operations and server behaviors:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Enables system variable changes at runtime:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: square; ">
<li class="listitem">
<p>
Enables server configuration changes to global
system variables with
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
GLOBAL
</code>
</a>
and
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables server configuration changes to global
system variables with
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
, if the user also has
<a class="link" href="privileges-provided.html#priv_persist-ro-variables-admin">
<code class="literal">
PERSIST_RO_VARIABLES_ADMIN
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables setting restricted session system variables
that require a special privilege. In effect,
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
implies
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
without explicitly granting
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
.
</p>
</li>
</ul>
</div>
<p>
See also
<a class="xref" href="system-variable-privileges.html" title="7.1.9.1 System Variable Privileges">
Section 7.1.9.1, “System Variable Privileges”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Enables changes to global transaction characteristics
(see
<a class="xref" href="set-transaction.html" title="15.3.7 SET TRANSACTION Statement">
Section 15.3.7, “SET TRANSACTION Statement”
</a>
).
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<a name="priv_table-encryption-admin">
</a>
<a class="link" href="privileges-provided.html#priv_table-encryption-admin">
<code class="literal">
TABLE_ENCRYPTION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250906528">
</a>
<a class="indexterm" name="idm46045250905040">
</a>
<p>
Enables a user to override default encryption settings when
<a class="link" href="server-system-variables.html#sysvar_table_encryption_privilege_check">
<code class="literal">
table_encryption_privilege_check
</code>
</a>
is enabled; see
<a class="xref" href="innodb-data-encryption.html#innodb-schema-tablespace-encryption-default" title="Defining an Encryption Default for Schemas and General Tablespaces">
Defining an Encryption Default for Schemas and General Tablespaces
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_telemetry-log-admin">
</a>
<a class="link" href="privileges-provided.html#priv_telemetry-log-admin">
<code class="literal">
TELEMETRY_LOG_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250898960">
</a>
<a class="indexterm" name="idm46045250897472">
</a>
<p>
Enables telemetry log configuration. This privilege is
defined by the
<code class="literal">
telemetry_log
</code>
plugin,
which is deployed through HeatWave on AWS.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_tp-connection-admin">
</a>
<a class="link" href="privileges-provided.html#priv_tp-connection-admin">
<code class="literal">
TP_CONNECTION_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250892640">
</a>
<a class="indexterm" name="idm46045250891152">
</a>
<p>
Enables connecting to the server with a privileged
connection. When the limit defined by
<a class="link" href="server-system-variables.html#sysvar_thread_pool_max_transactions_limit">
<code class="literal">
thread_pool_max_transactions_limit
</code>
</a>
has been reached, new connections are not permitted, unless
overridden by
<a class="link" href="server-system-variables.html#sysvar_thread_pool_longrun_trx_limit">
<code class="literal">
thread_pool_longrun_trx_limit
</code>
</a>
.
A privileged connection ignores the transaction limit and
permits connecting to the server to increase the transaction
limit, remove the limit, or kill running transactions. This
privilege is not granted to any user by default. To
establish a privileged connection, the user initiating a
connection must have the
<a class="link" href="privileges-provided.html#priv_tp-connection-admin">
<code class="literal">
TP_CONNECTION_ADMIN
</code>
</a>
privilege.
</p>
<p>
A privileged connection can execute statements and start
transactions when the limit defined by
<code class="literal">
thread_pool_max_transactions_limit
</code>
has
been reached. A privileged connection is placed in the
<code class="literal">
Admin
</code>
thread group. See
<a class="xref" href="thread-pool-operation.html#privileged-connections" title="Privileged Connections">
Privileged Connections
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_transaction-gtid-tag">
</a>
<a class="link" href="privileges-provided.html#priv_transaction-gtid-tag">
<code class="literal">
TRANSACTION_GTID_TAG
</code>
</a>
</p>
<a class="indexterm" name="idm46045250880048">
</a>
<a class="indexterm" name="idm46045250878560">
</a>
<p>
Required for setting the
<a class="link" href="replication-options-gtids.html#sysvar_gtid_next">
<code class="literal">
gtid_next
</code>
</a>
system variable
to
<code class="literal">
AUTOMATIC:
<em class="replaceable">
<code>
TAG
</code>
</em>
</code>
or
<code class="literal">
UUID:
<em class="replaceable">
<code>
TAG
</code>
</em>
:NUMBER
</code>
on a replication source server. In addition, at least one of
<a class="link" href="privileges-provided.html#priv_system-variables-admin">
<code class="literal">
SYSTEM_VARIABLES_ADMIN
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_session-variables-admin">
<code class="literal">
SESSION_VARIABLES_ADMIN
</code>
</a>
, or
<a class="link" href="privileges-provided.html#priv_replication-applier">
<code class="literal">
REPLICATION_APPLIER
</code>
</a>
is also
required to set
<code class="literal">
gtid_next
</code>
to one of these
values on the source.
</p>
<p>
The
<code class="literal">
REPLICATION_CHECKS_APPLIER
</code>
must also
have this privilege as well as the
<code class="literal">
REPLICATION_APPLIER
</code>
privilege to set
<code class="literal">
gtid_next
</code>
to
<code class="literal">
AUTOMATIC:
<em class="replaceable">
<code>
TAG
</code>
</em>
</code>
.
This is checked when starting the replication applier
thread.
</p>
<p>
This privilege is also required to set the
<a class="link" href="replication-options-gtids.html#sysvar_gtid_purged">
<code class="literal">
gtid_purged
</code>
</a>
server system
variable.
</p>
<p>
For more information about using tagged GTIDs, see the
description of
<a class="link" href="replication-options-gtids.html#sysvar_gtid_next">
<code class="literal">
gtid_next
</code>
</a>
,
as well as
<a class="xref" href="replication-mode-change-online.html" title="19.1.4 Changing GTID Mode on Online Servers">
Section 19.1.4, “Changing GTID Mode on Online Servers”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_version-token-admin">
</a>
<a class="link" href="privileges-provided.html#priv_version-token-admin">
<code class="literal">
VERSION_TOKEN_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250858704">
</a>
<a class="indexterm" name="idm46045250857216">
</a>
<p>
Enables execution of Version Tokens functions. This
privilege is defined by the
<code class="literal">
version_tokens
</code>
plugin; see
<a class="xref" href="version-tokens.html" title="7.6.6 Version Tokens">
Section 7.6.6, “Version Tokens”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="priv_xa-recover-admin">
</a>
<a class="link" href="privileges-provided.html#priv_xa-recover-admin">
<code class="literal">
XA_RECOVER_ADMIN
</code>
</a>
</p>
<a class="indexterm" name="idm46045250851856">
</a>
<a class="indexterm" name="idm46045250850368">
</a>
<p>
Enables execution of the
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
RECOVER
</code>
</a>
statement; see
<a class="xref" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
Section 15.3.8.1, “XA Transaction SQL Statements”
</a>
.
</p>
<p>
Prior to MySQL 8.4, any user could execute the
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
RECOVER
</code>
</a>
statement to discover the XID values for
outstanding prepared XA transactions, possibly leading to
commit or rollback of an XA transaction by a user other than
the one who started it. In MySQL 8.4,
<a class="link" href="xa-statements.html" title="15.3.8.1 XA Transaction SQL Statements">
<code class="literal">
XA
RECOVER
</code>
</a>
is permitted only to users who have the
<a class="link" href="privileges-provided.html#priv_xa-recover-admin">
<code class="literal">
XA_RECOVER_ADMIN
</code>
</a>
privilege,
which is expected to be granted only to administrative users
who have need for it. This might be the case, for example,
for administrators of an XA application if it has crashed
and it is necessary to find outstanding transactions started
by the application so they can be rolled back. This
privilege requirement prevents users from discovering the
XID values for outstanding prepared XA transactions other
than their own. It does not affect normal commit or rollback
of an XA transaction because the user who started it knows
its XID.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="privileges-provided-guidelines">
</a>
Privilege-Granting Guidelines
</h4>
</div>
</div>
</div>
<p>
It is a good idea to grant to an account only those privileges
that it needs. You should exercise particular caution in
granting the
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
and
administrative privileges:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
can be abused to read
into a database table any files that the MySQL server can
read on the server host. This includes all world-readable
files and files in the server's data directory. The table
can then be accessed using
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
to transfer its
contents to the client host.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_grant-option">
<code class="literal">
GRANT OPTION
</code>
</a>
enables users to
give their privileges to other users. Two users that have
different privileges and with the
<a class="link" href="privileges-provided.html#priv_grant-option">
<code class="literal">
GRANT
OPTION
</code>
</a>
privilege are able to combine privileges.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_alter">
<code class="literal">
ALTER
</code>
</a>
may be used to subvert
the privilege system by renaming tables.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_shutdown">
<code class="literal">
SHUTDOWN
</code>
</a>
can be abused to
deny service to other users entirely by terminating the
server.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
can be used to view
the plain text of currently executing statements, including
statements that set or change passwords.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
can be used to
terminate other sessions or change how the server operates.
</p>
</li>
<li class="listitem">
<p>
Privileges granted for the
<code class="literal">
mysql
</code>
system
database itself can be used to change passwords and other
access privilege information:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Passwords are stored encrypted, so a malicious user
cannot simply read them to know the plain text password.
However, a user with write access to the
<code class="literal">
mysql.user
</code>
system table
<code class="literal">
authentication_string
</code>
column can
change an account's password, and then connect to the
MySQL server using that account.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
or
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
granted for the
<code class="literal">
mysql
</code>
system database enable a user
to add privileges or modify existing privileges,
respectively.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="privileges-provided.html#priv_drop">
<code class="literal">
DROP
</code>
</a>
for the
<code class="literal">
mysql
</code>
system database enables a user
to remote privilege tables, or even the database itself.
</p>
</li>
</ul>
</div>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="static-dynamic-privileges">
</a>
Static Versus Dynamic Privileges
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045250809920">
</a>
<a class="indexterm" name="idm46045250808432">
</a>
<a class="indexterm" name="idm46045250807360">
</a>
<p>
MySQL supports static and dynamic privileges:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Static privileges are built in to the server. They are
always available to be granted to user accounts and cannot
be unregistered.
</p>
</li>
<li class="listitem">
<p>
Dynamic privileges can be registered and unregistered at
runtime. This affects their availability: A dynamic
privilege that has not been registered cannot be granted.
</p>
</li>
</ul>
</div>
<p>
For example, the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
privileges are static and
always available, whereas a dynamic privilege becomes available
only if the component that implements it has been enabled.
</p>
<p>
The remainder of this section describes how dynamic privileges
work in MySQL. The discussion uses the term
<span class="quote">
“
<span class="quote">
components
</span>
”
</span>
but applies equally to plugins.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Server administrators should be aware of which server
components define dynamic privileges. For MySQL distributions,
documentation of components that define dynamic privileges
describes those privileges.
</p>
<p>
Third-party components may also define dynamic privileges; an
administrator should understand those privileges and not
install components that might conflict or compromise server
operation. For example, one component conflicts with another
if both define a privilege with the same name. Component
developers can reduce the likelihood of this occurrence by
choosing privilege names having a prefix based on the
component name.
</p>
</div>
<p>
The server maintains the set of registered dynamic privileges
internally in memory. Unregistration occurs at server shutdown.
</p>
<p>
Normally, a component that defines dynamic privileges registers
them when it is installed, during its initialization sequence.
When uninstalled, a component does not unregister its registered
dynamic privileges. (This is current practice, not a
requirement. That is, components could, but do not, unregister
at any time privileges they register.)
</p>
<p>
No warning or error occurs for attempts to register an already
registered dynamic privilege. Consider the following sequence of
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa38998144"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSTALL</span> <span class="token keyword">COMPONENT</span> <span class="token string">'my_component'</span><span class="token punctuation">;</span>
<span class="token keyword">UNINSTALL</span> <span class="token keyword">COMPONENT</span> <span class="token string">'my_component'</span><span class="token punctuation">;</span>
<span class="token keyword">INSTALL</span> <span class="token keyword">COMPONENT</span> <span class="token string">'my_component'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The first
<a class="link" href="install-component.html" title="15.7.4.3 INSTALL COMPONENT Statement">
<code class="literal">
INSTALL COMPONENT
</code>
</a>
statement registers any privileges defined by component
<code class="literal">
my_component
</code>
, but
<a class="link" href="uninstall-component.html" title="15.7.4.5 UNINSTALL COMPONENT Statement">
<code class="literal">
UNINSTALL COMPONENT
</code>
</a>
does not
unregister them. For the second
<a class="link" href="install-component.html" title="15.7.4.3 INSTALL COMPONENT Statement">
<code class="literal">
INSTALL
COMPONENT
</code>
</a>
statement, the component privileges it
registers are found to be already registered, but no warnings or
errors occur.
</p>
<a class="indexterm" name="idm46045250789472">
</a>
<a class="indexterm" name="idm46045250787984">
</a>
<a class="indexterm" name="idm46045250786496">
</a>
<p>
Dynamic privileges apply only at the global level. The server
stores information about current assignments of dynamic
privileges to user accounts in the
<code class="literal">
mysql.global_grants
</code>
system table:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The server automatically registers privileges named in
<code class="literal">
global_grants
</code>
during server startup
(unless the
<a class="link" href="server-options.html#option_mysqld_skip-grant-tables">
<code class="option">
--skip-grant-tables
</code>
</a>
option is
given).
</p>
</li>
<li class="listitem">
<p>
The
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements modify the
contents of
<code class="literal">
global_grants
</code>
.
</p>
</li>
<li class="listitem">
<p>
Dynamic privilege assignments listed in
<code class="literal">
global_grants
</code>
are persistent. They are
not removed at server shutdown.
</p>
</li>
</ul>
</div>
<p>
Example: The following statement grants to user
<code class="literal">
u1
</code>
the privileges required to control
replication (including Group Replication) on a replica, and to
modify system variables:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42845977"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">GRANT</span> REPLICATION_SLAVE_ADMIN<span class="token punctuation">,</span> GROUP_REPLICATION_ADMIN<span class="token punctuation">,</span> BINLOG_ADMIN
<span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> <span class="token string">'u1'</span>@<span class="token string">'localhost'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Granted dynamic privileges appear in the output from the
<code class="literal">
SHOW GRANTS
</code>
statement and the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-user-privileges-table.html" title="28.3.46 The INFORMATION_SCHEMA USER_PRIVILEGES Table">
<code class="literal">
USER_PRIVILEGES
</code>
</a>
table.
</p>
<p>
For
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
at the global level, any
named privileges not recognized as static are checked against
the current set of registered dynamic privileges and granted if
found. Otherwise, an error occurs to indicate an unknown
privilege identifier.
</p>
<p>
For
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
and
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
the meaning of
<code class="literal">
ALL [PRIVILEGES]
</code>
at the global level includes
all static global privileges, as well as all currently
registered dynamic privileges:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
GRANT ALL
</code>
at the global level grants all
static global privileges and all currently registered
dynamic privileges. A dynamic privilege registered
subsequent to execution of the
<code class="literal">
GRANT
</code>
statement is not granted retroactively to any account.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
REVOKE ALL
</code>
at the global level revokes
all granted static global privileges and all granted dynamic
privileges.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="flush.html#flush-privileges">
<code class="literal">
FLUSH PRIVILEGES
</code>
</a>
statement
reads the
<code class="literal">
global_grants
</code>
table for dynamic
privilege assignments and registers any unregistered privileges
found there.
</p>
<p>
For descriptions of the dynamic privileges provided by MySQL
Server and components included in MySQL distributions, see
<a class="xref" href="privileges-provided.html" title="8.2.2 Privileges Provided by MySQL">
Section 8.2.2, “Privileges Provided by MySQL”
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="dynamic-privileges-migration-from-super">
</a>
Migrating Accounts from SUPER to Dynamic Privileges
</h4>
</div>
</div>
</div>
<p>
In MySQL 8.4, many operations that previously
required the
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege are
also associated with a dynamic privilege of more limited scope.
(For descriptions of these privileges, see
<a class="xref" href="privileges-provided.html" title="8.2.2 Privileges Provided by MySQL">
Section 8.2.2, “Privileges Provided by MySQL”
</a>
.) Each such operation can
be permitted to an account by granting the associated dynamic
privilege rather than
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
. This
change improves security by enabling DBAs to avoid granting
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
and tailor user privileges
more closely to the operations permitted.
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
is now deprecated; expect
it to be removed in a future version of MySQL.
</p>
<p>
When removal of
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
occurs,
operations that formerly required
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
fail unless accounts
granted
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
are migrated to the
appropriate dynamic privileges. Use the following instructions
to accomplish that goal so that accounts are ready prior to
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
removal:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Execute this query to identify accounts that are granted
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa93849218"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> GRANTEE <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span>USER_PRIVILEGES
<span class="token keyword">WHERE</span> PRIVILEGE_TYPE <span class="token operator">=</span> <span class="token string">'SUPER'</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
For each account identified by the preceding query,
determine the operations for which it needs
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
. Then grant the dynamic
privileges corresponding to those operations, and revoke
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
.
</p>
<p>
For example, if
<code class="literal">
'u1'@'localhost'
</code>
requires
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
for binary log purging
and system variable modification, these statements make the
required changes to the account:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa71126189"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">GRANT</span> BINLOG_ADMIN<span class="token punctuation">,</span> SYSTEM_VARIABLES_ADMIN <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> <span class="token string">'u1'</span>@<span class="token string">'localhost'</span><span class="token punctuation">;</span>
<span class="token keyword">REVOKE</span> <span class="token keyword">SUPER</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> <span class="token string">'u1'</span>@<span class="token string">'localhost'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
After you have modified all applicable accounts, the
<code class="literal">
INFORMATION_SCHEMA
</code>
query in the first
step should produce an empty result set.
</p>
</li>
</ol>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-mgmd.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-programs-ndb-mgmd">
</a>
25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045107203056">
</a>
<a class="indexterm" name="idm46045107202144">
</a>
<a class="indexterm" name="idm46045107200784">
</a>
<a class="indexterm" name="idm46045107199424">
</a>
<a class="indexterm" name="idm46045107198048">
</a>
<p>
The management server is the process that reads the cluster
configuration file and distributes this information to all nodes
in the cluster that request it. It also maintains a log of
cluster activities. Management clients can connect to the
management server and check the cluster's status.
</p>
<a class="indexterm" name="idm46045107195824">
</a>
<a class="indexterm" name="idm46045107194336">
</a>
<a class="indexterm" name="idm46045107192848">
</a>
<a class="indexterm" name="idm46045107191344">
</a>
<p>
All options that can be used with
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
are shown in the following table. Additional descriptions follow
the table.
</p>
<p>
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="option_ndb_mgmd_bind-address">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_bind-address">
<code class="option">
--bind-address=
<em class="replaceable">
<code>
host
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045107184688">
</a>
<a class="indexterm" name="idm46045107183200">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for bind-address">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--bind-address=host
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Causes the management server to bind to a specific network
interface (host name or IP address). This option has no
default value.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_character-sets-dir">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_character-sets-dir">
<code class="option">
--character-sets-dir
</code>
</a>
</p>
<a class="indexterm" name="idm46045107168880">
</a>
<a class="indexterm" name="idm46045107167424">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for character-sets-dir">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--character-sets-dir=path
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Directory containing character sets.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_cluster-config-suffix">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_cluster-config-suffix">
<code class="option">
cluster-config-suffix
</code>
</a>
</p>
<a class="indexterm" name="idm46045107157680">
</a>
<a class="indexterm" name="idm46045107156224">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for cluster-config-suffix">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--cluster-config-suffix=name
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Override defaults group suffix when reading cluster
configuration sections in
<code class="filename">
my.cnf
</code>
; used
in testing.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_config-cache">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-cache">
<code class="option">
--config-cache
</code>
</a>
</p>
<a class="indexterm" name="idm46045107141264">
</a>
<a class="indexterm" name="idm46045107139776">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for config-cache">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--config-cache[=TRUE|FALSE]
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Boolean
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
TRUE
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
This option, whose default value is
<code class="literal">
1
</code>
(or
<code class="literal">
TRUE
</code>
, or
<code class="literal">
ON
</code>
), can be
used to disable the management server's configuration
cache, so that it reads its configuration from
<code class="filename">
config.ini
</code>
every time it starts (see
<a class="xref" href="mysql-cluster-config-file.html" title="25.4.3 NDB Cluster Configuration Files">
Section 25.4.3, “NDB Cluster Configuration Files”
</a>
). You can do
this by starting the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
process
with any one of the following options:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
<code class="option">
--config-cache=0
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="option">
--config-cache=FALSE
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="option">
--config-cache=OFF
</code>
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_skip-config-cache">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_skip-config-cache">
<code class="option">
--skip-config-cache
</code>
</a>
</p>
</li>
</ul>
</div>
<p>
Using one of the options just listed is effective only if
the management server has no stored configuration at the
time it is started. If the management server finds any
configuration cache files, then the
<code class="option">
--config-cache
</code>
option or the
<code class="option">
--skip-config-cache
</code>
option is ignored.
Therefore, to disable configuration caching, the option
should be used the
<span class="emphasis">
<em>
first
</em>
</span>
time that the
management server is started. Otherwise—that is, if
you wish to disable configuration caching for a management
server that has
<span class="emphasis">
<em>
already
</em>
</span>
created a
configuration cache—you must stop the management
server, delete any existing configuration cache files
manually, then restart the management server with
<code class="option">
--skip-config-cache
</code>
(or with
<code class="option">
--config-cache
</code>
set equal to 0,
<code class="literal">
OFF
</code>
, or
<code class="literal">
FALSE
</code>
).
</p>
<p>
Configuration cache files are normally created in a
directory named
<code class="filename">
mysql-cluster
</code>
under the
installation directory (unless this location has been
overridden using the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_configdir">
<code class="option">
--configdir
</code>
</a>
option). Each
time the management server updates its configuration data,
it writes a new cache file. The files are named sequentially
in order of creation using the following format:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa42258721"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple">ndb_<em class="replaceable">node<span class="token operator">-</span>id</em>_config<span class="token punctuation">.</span>bin<span class="token punctuation">.</span><em class="replaceable">seq<span class="token operator">-</span>number</em></code></pre>
</div>
<p>
<em class="replaceable">
<code>
node-id
</code>
</em>
is the management
server's node ID;
<em class="replaceable">
<code>
seq-number
</code>
</em>
is a sequence number, beginning with 1. For example, if the
management server's node ID is 5, then the first three
configuration cache files would, when they are created, be
named
<code class="filename">
ndb_5_config.bin.1
</code>
,
<code class="filename">
ndb_5_config.bin.2
</code>
, and
<code class="filename">
ndb_5_config.bin.3
</code>
.
</p>
<p>
If your intent is to purge or reload the configuration cache
without actually disabling caching, you should start
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
with one of the options
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
or
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
instead of
<code class="option">
--skip-config-cache
</code>
.
</p>
<p>
To re-enable the configuration cache, simply restart the
management server, but without the
<code class="option">
--config-cache
</code>
or
<code class="option">
--skip-config-cache
</code>
option that was used
previously to disable the configuration cache.
</p>
<p>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
does not check for the
configuration directory
(
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_configdir">
<code class="option">
--configdir
</code>
</a>
) or attempts
to create one when
<code class="option">
--skip-config-cache
</code>
is
used. (Bug #13428853)
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_config-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file=
<em class="replaceable">
<code>
filename
</code>
</em>
</code>
</a>
,
<code class="option">
-f
<em class="replaceable">
<code>
filename
</code>
</em>
</code>
</p>
<a class="indexterm" name="idm46045107090752">
</a>
<a class="indexterm" name="idm46045107089264">
</a>
<a class="indexterm" name="idm46045107087776">
</a>
<a class="indexterm" name="idm46045107086288">
</a>
<a class="indexterm" name="idm46045107084800">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for config-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--config-file=file
</code>
</td>
</tr>
<tr>
<th>
Disabled by
</th>
<td>
<code class="literal">
skip-config-file
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
File name
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Instructs the management server as to which file it should
use for its configuration file. By default, the management
server looks for a file named
<code class="filename">
config.ini
</code>
in the same directory as the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
executable; otherwise the file
name and location must be specified explicitly.
</p>
<p>
This option has no default value, and is ignored unless the
management server is forced to read the configuration file,
either because
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
was started with
the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
or
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
option, or
because the management server could not find any
configuration cache. If
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file
</code>
</a>
is specified
without either of
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
or
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
,
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
refuses to start.
</p>
<p>
The
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file
</code>
</a>
option is
also read if
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
was started with
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-cache">
<code class="option">
--config-cache=OFF
</code>
</a>
. See
<a class="xref" href="mysql-cluster-config-file.html" title="25.4.3 NDB Cluster Configuration Files">
Section 25.4.3, “NDB Cluster Configuration Files”
</a>
, for more
information.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_configdir">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_configdir">
<code class="option">
--configdir=
<em class="replaceable">
<code>
dir_name
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045107052800">
</a>
<a class="indexterm" name="idm46045107051312">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for configdir">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<p class="valid-value">
<code class="literal">
--configdir=directory
</code>
</p>
<p class="valid-value">
<code class="literal">
--config-dir=directory
</code>
</p>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
File name
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
$INSTALLDIR/mysql-cluster
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Specifies the cluster management server's configuration
cache directory. This must be an absolute path. Otherwise,
the management server refuses to start.
</p>
<p>
<code class="option">
--config-dir
</code>
is an alias for this option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_connect-retries">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_connect-retries">
<code class="option">
--connect-retries
</code>
</a>
</p>
<a class="indexterm" name="idm46045107034768">
</a>
<a class="indexterm" name="idm46045107033280">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-retries">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-retries=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Number of times to retry connection before giving up.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_connect-retry-delay">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_connect-retry-delay">
<code class="option">
--connect-retry-delay
</code>
</a>
</p>
<a class="indexterm" name="idm46045107014192">
</a>
<a class="indexterm" name="idm46045107012736">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-retry-delay">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-retry-delay=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
5
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
5
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Number of seconds to wait between attempts to contact
management server.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_connect-string">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_connect-string">
<code class="option">
--connect-string
</code>
</a>
</p>
<a class="indexterm" name="idm46045106993488">
</a>
<a class="indexterm" name="idm46045106992000">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-string">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-string=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Same as --ndb-connectstring.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_core-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_core-file">
<code class="option">
--core-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045106977728">
</a>
<a class="indexterm" name="idm46045106976240">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for core-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--core-file
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Write core file on error; used in debugging.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_daemon">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_daemon">
<code class="option">
--daemon
</code>
</a>
,
<code class="option">
-d
</code>
</p>
<a class="indexterm" name="idm46045106966224">
</a>
<a class="indexterm" name="idm46045106964736">
</a>
<a class="indexterm" name="idm46045106963248">
</a>
<a class="indexterm" name="idm46045106961760">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for daemon">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--daemon
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Instructs
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
to start as a daemon
process. This is the default behavior.
</p>
<p>
This option has no effect when running
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
on Windows platforms.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_defaults-extra-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_defaults-extra-file">
<code class="option">
--defaults-extra-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045106948928">
</a>
<a class="indexterm" name="idm46045106947472">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-extra-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-extra-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given file after global files are read.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_defaults-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_defaults-file">
<code class="option">
--defaults-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045106933184">
</a>
<a class="indexterm" name="idm46045106931696">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read default options from given file only.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_defaults-group-suffix">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_defaults-group-suffix">
<code class="option">
--defaults-group-suffix
</code>
</a>
</p>
<a class="indexterm" name="idm46045106917424">
</a>
<a class="indexterm" name="idm46045106915968">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-group-suffix">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-group-suffix=string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Also read groups with concat(group, suffix).
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_help">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_help">
<code class="option">
--help
</code>
</a>
</p>
<a class="indexterm" name="idm46045106901904">
</a>
<a class="indexterm" name="idm46045106900416">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for help">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--help
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display help text and exit.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_initial">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
</p>
<a class="indexterm" name="idm46045106890848">
</a>
<a class="indexterm" name="idm46045106889360">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for initial">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--initial
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Configuration data is cached internally, rather than being
read from the cluster global configuration file each time
the management server is started (see
<a class="xref" href="mysql-cluster-config-file.html" title="25.4.3 NDB Cluster Configuration Files">
Section 25.4.3, “NDB Cluster Configuration Files”
</a>
). Using the
<code class="option">
--initial
</code>
option overrides this behavior,
by forcing the management server to delete any existing
cache files, and then to re-read the configuration data from
the cluster configuration file and to build a new cache.
</p>
<p>
This differs in two ways from the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
option. First,
<code class="option">
--reload
</code>
forces the server to check the
configuration file against the cache and reload its data
only if the contents of the file are different from the
cache. Second,
<code class="option">
--reload
</code>
does not delete any
existing cache files.
</p>
<p>
If
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
is invoked with
<code class="option">
--initial
</code>
but cannot find a global
configuration file, the management server cannot start.
</p>
<p>
When a management server starts, it checks for another
management server in the same NDB Cluster and tries to use
the other management server's configuration data. This
behavior has implications when performing a rolling restart
of an NDB Cluster with multiple management nodes. See
<a class="xref" href="mysql-cluster-rolling-restart.html" title="25.6.5 Performing a Rolling Restart of an NDB Cluster">
Section 25.6.5, “Performing a Rolling Restart of an NDB Cluster”
</a>
, for more
information.
</p>
<p>
When used together with the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file
</code>
</a>
option, the
cache is cleared only if the configuration file is actually
found.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_install">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_install">
<code class="option">
--install[=
<em class="replaceable">
<code>
name
</code>
</em>
]
</code>
</a>
</p>
<a class="indexterm" name="idm46045106870048">
</a>
<a class="indexterm" name="idm46045106868560">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for install">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--install[=name]
</code>
</td>
</tr>
<tr>
<th>
Platform Specific
</th>
<td>
Windows
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
ndb_mgmd
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Causes
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
to be installed as a
Windows service. Optionally, you can specify a name for the
service; if not set, the service name defaults to
<code class="literal">
ndb_mgmd
</code>
. Although it is preferable to
specify other
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
program options in
a
<code class="filename">
my.ini
</code>
or
<code class="filename">
my.cnf
</code>
configuration file, it is possible to use them together with
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_install">
<code class="option">
--install
</code>
</a>
. However, in such
cases, the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_install">
<code class="option">
--install
</code>
</a>
option
must be specified first, before any other options are given,
for the Windows service installation to succeed.
</p>
<p>
It is generally not advisable to use this option together
with the
<a class="link" href="mysql-cluster-programs-ndbd.html#option_ndbd_initial">
<code class="option">
--initial
</code>
</a>
option,
since this causes the configuration cache to be wiped and
rebuilt every time the service is stopped and started. Care
should also be taken if you intend to use any other
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
options that affect the starting
of the management server, and you should make absolutely
certain you fully understand and allow for any possible
consequences of doing so.
</p>
<p>
The
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_install">
<code class="option">
--install
</code>
</a>
option has no
effect on non-Windows platforms.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_interactive">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_interactive">
<code class="option">
--interactive
</code>
</a>
</p>
<a class="indexterm" name="idm46045106840560">
</a>
<a class="indexterm" name="idm46045106839072">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for interactive">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--interactive
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Starts
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
in interactive mode; that
is, an
<a class="link" href="mysql-cluster-programs-ndb-mgm.html" title="25.5.5 ndb_mgm — The NDB Cluster Management Client">
<span class="command">
<strong>
ndb_mgm
</strong>
</span>
</a>
client session is started
as soon as the management server is running. This option
does not start any other NDB Cluster nodes.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_log-name">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_log-name">
<code class="option">
--log-name=
<em class="replaceable">
<code>
name
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045106826288">
</a>
<a class="indexterm" name="idm46045106824800">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for log-name">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--log-name=name
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
MgmtSrvr
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Provides a name to be used for this node in the cluster log.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_login-path">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_login-path">
<code class="option">
--login-path
</code>
</a>
</p>
<a class="indexterm" name="idm46045106810592">
</a>
<a class="indexterm" name="idm46045106809104">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for login-path">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--login-path=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given path from login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_no-login-paths">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_no-login-paths">
<code class="option">
--no-login-paths
</code>
</a>
</p>
<a class="indexterm" name="idm46045106794832">
</a>
<a class="indexterm" name="idm46045106793344">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-login-paths">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-login-paths
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Skips reading options from the login path file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_mycnf">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_mycnf">
<code class="option">
--mycnf
</code>
</a>
</p>
<a class="indexterm" name="idm46045106783680">
</a>
<a class="indexterm" name="idm46045106782192">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for mycnf">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--mycnf
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read configuration data from the
<code class="filename">
my.cnf
</code>
file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-connectstring">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-connectstring">
<code class="option">
--ndb-connectstring
</code>
</a>
</p>
<a class="indexterm" name="idm46045106771664">
</a>
<a class="indexterm" name="idm46045106770208">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-connectstring">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-connectstring=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Set connection string. Syntax:
<code class="literal">
[nodeid=
<em class="replaceable">
<code>
id
</code>
</em>
;][host=]
<em class="replaceable">
<code>
hostname
</code>
</em>
[:
<em class="replaceable">
<code>
port
</code>
</em>
]
</code>
.
Overrides entries in
<code class="literal">
NDB_CONNECTSTRING
</code>
and
<code class="filename">
my.cnf
</code>
. Ignored if
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file
</code>
</a>
is specified;
a warning is issued if both options are used concurrently.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-mgm-tls">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-mgm-tls">
<code class="option">
--ndb-mgm-tls
</code>
</a>
</p>
<a class="indexterm" name="idm46045106751280">
</a>
<a class="indexterm" name="idm46045106749792">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-mgm-tls">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-mgm-tls=level
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Enumeration
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
relaxed
</code>
</td>
</tr>
<tr>
<th>
Valid Values
</th>
<td>
<p class="valid-value">
<code class="literal">
relaxed
</code>
</p>
<p class="valid-value">
<code class="literal">
strict
</code>
</p>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Sets the level of TLS support required to connect to the
management server; one of
<code class="literal">
relaxed
</code>
or
<code class="literal">
strict
</code>
.
<code class="literal">
relaxed
</code>
(the
default) means that a TLS connection is attempted, but
success is not required;
<code class="literal">
strict
</code>
means
that TLS is required to connect.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-mgmd-host">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-mgmd-host">
<code class="option">
--ndb-mgmd-host
</code>
</a>
</p>
<a class="indexterm" name="idm46045106728672">
</a>
<a class="indexterm" name="idm46045106727184">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-mgmd-host">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-mgmd-host=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Same as --ndb-connectstring.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-nodeid">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-nodeid">
<code class="option">
--ndb-nodeid
</code>
</a>
</p>
<a class="indexterm" name="idm46045106712960">
</a>
<a class="indexterm" name="idm46045106711472">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-nodeid">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-nodeid=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Set node ID for this node, overriding any ID set by
--ndb-connectstring.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-optimized-node-selection">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-optimized-node-selection">
<code class="option">
--ndb-optimized-node-selection
</code>
</a>
</p>
<a class="indexterm" name="idm46045106697056">
</a>
<a class="indexterm" name="idm46045106695552">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-optimized-node-selection">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-optimized-node-selection
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Enable optimizations for selection of nodes for
transactions. Enabled by default; use
<code class="option">
--skip-ndb-optimized-node-selection
</code>
to
disable.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_ndb-tls-search-path">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-tls-search-path">
<code class="option">
--ndb-tls-search-path
</code>
</a>
</p>
<a class="indexterm" name="idm46045106685200">
</a>
<a class="indexterm" name="idm46045106683744">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-tls-search-path">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-tls-search-path=list
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Path name
</td>
</tr>
<tr>
<th>
Default Value (Unix)
</th>
<td>
<code class="literal">
$HOME/ndb-tls
</code>
</td>
</tr>
<tr>
<th>
Default Value (Windows)
</th>
<td>
<code class="literal">
$HOMEDIR/ndb-tls
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Specify a list of directories to search for a CA file. On
Unix platforms, the directory names are separated by colons
(
<code class="literal">
:
</code>
); on Windows systems, the semicolon
character (
<code class="literal">
;
</code>
) is used as the separator. A
directory reference may be relative or absolute; it may
contain one or more environment variables, each denoted by a
prefixed dollar sign (
<code class="literal">
$
</code>
), and expanded
prior to use.
</p>
<p>
Searching begins with the leftmost named directory and
proceeds from left to right until a file is found. An empty
string denotes an empty search path, which causes all
searches to fail. A string consisting of a single dot
(
<code class="literal">
.
</code>
) indicates that the search path
limited to the current working directory.
</p>
<p>
If no search path is supplied, the compiled-in default value
is used. This value depends on the platform used: On
Windows, this is
<code class="literal">
\ndb-tls
</code>
; on other
platforms (including Linux), it is
<code class="literal">
$HOME/ndb-tls
</code>
. This can be overridden by
compiling NDB Cluster using
<a class="link" href="source-configuration-options.html#option_cmake_with_ndb_tls_search_path">
<code class="option">
-DWITH_NDB_TLS_SEARCH_PATH
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_no-nodeid-checks">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_no-nodeid-checks">
<code class="option">
--no-nodeid-checks
</code>
</a>
</p>
<a class="indexterm" name="idm46045106659920">
</a>
<a class="indexterm" name="idm46045106658432">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-nodeid-checks">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-nodeid-checks
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not perform any checks of node IDs.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_nodaemon">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_nodaemon">
<code class="option">
--nodaemon
</code>
</a>
</p>
<a class="indexterm" name="idm46045106648720">
</a>
<a class="indexterm" name="idm46045106647232">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for nodaemon">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--nodaemon
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Instructs
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
not to start as a
daemon process.
</p>
<p>
The default behavior for
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
on
Windows is to run in the foreground, making this option
unnecessary on Windows platforms.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_no-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_no-defaults">
<code class="option">
--no-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045106634464">
</a>
<a class="indexterm" name="idm46045106632976">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not read default options from any option file other than
login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_nowait-nodes">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_nowait-nodes">
<code class="option">
--nowait-nodes
</code>
</a>
</p>
<a class="indexterm" name="idm46045106623264">
</a>
<a class="indexterm" name="idm46045106621776">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for nowait-nodes">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--nowait-nodes=list
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Numeric
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
1
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
255
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
When starting an NDB Cluster is configured with two
management nodes, each management server normally checks to
see whether the other
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
is also
operational and whether the other management server's
configuration is identical to its own. However, it is
sometimes desirable to start the cluster with only one
management node (and perhaps to allow the other
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
to be started later). This
option causes the management node to bypass any checks for
any other management nodes whose node IDs are passed to this
option, permitting the cluster to start as though configured
to use only the management node that was started.
</p>
<p>
For purposes of illustration, consider the following portion
of a
<code class="filename">
config.ini
</code>
file (where we have
omitted most of the configuration parameters that are not
relevant to this example):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa77114977"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[ndbd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 1</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.101</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 2</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.102</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 3</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.103</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 4</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.104</span>
<span class="token selector">[ndb_mgmd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 10</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.150</span>
<span class="token selector">[ndb_mgmd]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 11</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.151</span>
<span class="token selector">[api]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 20</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.200</span>
<span class="token selector">[api]</span>
<span class="token constant">NodeId</span> <span class="token attr-value"><span class="token punctuation">=</span> 21</span>
<span class="token constant">HostName</span> <span class="token attr-value"><span class="token punctuation">=</span> 198.51.100.201</span></code></pre>
</div>
<p>
Assume that you wish to start this cluster using only the
management server having node ID
<code class="literal">
10
</code>
and
running on the host having the IP address 198.51.100.150.
(Suppose, for example, that the host computer on which you
intend to the other management server is temporarily
unavailable due to a hardware failure, and you are waiting
for it to be repaired.) To start the cluster in this way,
use a command line on the machine at 198.51.100.150 to enter
the following command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa79451447"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">ndb_mgmd</span> <span class="token constant">--ndb-nodeid</span><span class="token attr-value"><span class="token punctuation">=</span>10</span> <span class="token constant">--nowait-nodes</span><span class="token attr-value"><span class="token punctuation">=</span>11</span></code></pre>
</div>
<p>
As shown in the preceding example, when using
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_nowait-nodes">
<code class="option">
--nowait-nodes
</code>
</a>
, you must
also use the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_ndb-nodeid">
<code class="option">
--ndb-nodeid
</code>
</a>
option to specify the node ID of this
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
process.
</p>
<p>
You can then start each of the cluster's data nodes in
the usual way. If you wish to start and use the second
management server in addition to the first management server
at a later time without restarting the data nodes, you must
start each data node with a connection string that
references both management servers, like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa38978225"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">ndbd</span> <span class="token property">-c</span> 198<span class="token punctuation">.</span>51<span class="token punctuation">.</span>100<span class="token punctuation">.</span>150<span class="token punctuation">,</span>198<span class="token punctuation">.</span>51<span class="token punctuation">.</span>100<span class="token punctuation">.</span>151</code></pre>
</div>
<p>
The same is true with regard to the connection string used
with any
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
processes that you wish
to start as NDB Cluster SQL nodes connected to this cluster.
See
<a class="xref" href="mysql-cluster-connection-strings.html" title="25.4.3.3 NDB Cluster Connection Strings">
Section 25.4.3.3, “NDB Cluster Connection Strings”
</a>
, for
more information.
</p>
<p>
When used with
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
, this option
affects the behavior of the management node with regard to
other management nodes only. Do not confuse it with the
<a class="link" href="mysql-cluster-programs-ndbd.html#option_ndbd_nowait-nodes">
<code class="option">
--nowait-nodes
</code>
</a>
option used with
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
or
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
to
permit a cluster to start with fewer than its full
complement of data nodes; when used with data nodes, this
option affects their behavior only with regard to other data
nodes.
</p>
<p>
Multiple management node IDs may be passed to this option as
a comma-separated list. Each node ID must be no less than 1
and no greater than 255. In practice, it is quite rare to
use more than two management servers for the same NDB
Cluster (or to have any need for doing so); in most cases
you need to pass to this option only the single node ID for
the one management server that you do not wish to use when
starting the cluster.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
When you later start the
<span class="quote">
“
<span class="quote">
missing
</span>
”
</span>
management
server, its configuration must match that of the
management server that is already in use by the cluster.
Otherwise, it fails the configuration check performed by
the existing management server, and does not start.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_print-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_print-defaults">
<code class="option">
--print-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045106576112">
</a>
<a class="indexterm" name="idm46045106574624">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for print-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--print-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Print program argument list and exit.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_print-full-config">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_print-full-config">
<code class="option">
--print-full-config
</code>
</a>
,
<code class="option">
-P
</code>
</p>
<a class="indexterm" name="idm46045106564432">
</a>
<a class="indexterm" name="idm46045106562976">
</a>
<a class="indexterm" name="idm46045106561472">
</a>
<a class="indexterm" name="idm46045106559984">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for print-full-config">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--print-full-config
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Shows extended information regarding the configuration of
the cluster. With this option on the command line the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
process prints information about
the cluster setup including an extensive list of the cluster
configuration sections as well as parameters and their
values. Normally used together with the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file
</code>
</a>
(
<code class="option">
-f
</code>
) option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_reload">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
</p>
<a class="indexterm" name="idm46045106547472">
</a>
<a class="indexterm" name="idm46045106545984">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for reload">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--reload
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
NDB Cluster configuration data is stored internally rather
than being read from the cluster global configuration file
each time the management server is started (see
<a class="xref" href="mysql-cluster-config-file.html" title="25.4.3 NDB Cluster Configuration Files">
Section 25.4.3, “NDB Cluster Configuration Files”
</a>
). Using this
option forces the management server to check its internal
data store against the cluster configuration file and to
reload the configuration if it finds that the configuration
file does not match the cache. Existing configuration cache
files are preserved, but not used.
</p>
<p>
This differs in two ways from the
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
option. First,
<code class="option">
--initial
</code>
causes all cache files to be
deleted. Second,
<code class="option">
--initial
</code>
forces the
management server to re-read the global configuration file
and construct a new cache.
</p>
<p>
If the management server cannot find a global configuration
file, then the
<code class="option">
--reload
</code>
option is ignored.
</p>
<p>
When
<code class="option">
--reload
</code>
is used, the management
server must be able to communicate with data nodes and any
other management servers in the cluster before it attempts
to read the global configuration file; otherwise, the
management server fails to start. This can happen due to
changes in the networking environment, such as new IP
addresses for nodes or an altered firewall configuration. In
such cases, you must use
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
instead to force
the existing cached configuration to be discarded and
reloaded from the file. See
<a class="xref" href="mysql-cluster-rolling-restart.html" title="25.6.5 Performing a Rolling Restart of an NDB Cluster">
Section 25.6.5, “Performing a Rolling Restart of an NDB Cluster”
</a>
, for
additional information.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_remove">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_remove">
<code class="option">
--remove[=name]
</code>
</a>
</p>
<a class="indexterm" name="idm46045106528656">
</a>
<a class="indexterm" name="idm46045106527168">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for remove">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--remove[=name]
</code>
</td>
</tr>
<tr>
<th>
Platform Specific
</th>
<td>
Windows
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
ndb_mgmd
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Remove a management server process that has been installed
as a Windows service, optionally specifying the name of the
service to be removed. Applies only to Windows platforms.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_skip-config-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_skip-config-file">
<code class="option">
--skip-config-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045106510656">
</a>
<a class="indexterm" name="idm46045106509168">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for skip-config-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--skip-config-file
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not read cluster configuration file; ignore
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_initial">
<code class="option">
--initial
</code>
</a>
and
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_reload">
<code class="option">
--reload
</code>
</a>
options if
specified.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_usage">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_usage">
<code class="option">
--usage
</code>
</a>
</p>
<a class="indexterm" name="idm46045106497600">
</a>
<a class="indexterm" name="idm46045106496112">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for usage">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--usage
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display help text and exit; same as --help.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_verbose">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_verbose">
<code class="option">
--verbose
</code>
</a>
,
<code class="option">
-v
</code>
</p>
<a class="indexterm" name="idm46045106486000">
</a>
<a class="indexterm" name="idm46045106484512">
</a>
<a class="indexterm" name="idm46045106483024">
</a>
<a class="indexterm" name="idm46045106481536">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for verbose">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--verbose
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Remove a management server process that has been installed
as a Windows service, optionally specifying the name of the
service to be removed. Applies only to Windows platforms.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_mgmd_version">
</a>
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_version">
<code class="option">
--version
</code>
</a>
</p>
<a class="indexterm" name="idm46045106471744">
</a>
<a class="indexterm" name="idm46045106470256">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for version">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--version
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display version information and exit.
</p>
</li>
</ul>
</div>
<p>
It is not strictly necessary to specify a connection string when
starting the management server. However, if you are using more
than one management server, a connection string should be
provided and each node in the cluster should specify its node ID
explicitly.
</p>
<p>
See
<a class="xref" href="mysql-cluster-connection-strings.html" title="25.4.3.3 NDB Cluster Connection Strings">
Section 25.4.3.3, “NDB Cluster Connection Strings”
</a>
, for
information about using connection strings.
<a class="xref" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
Section 25.5.4, “ndb_mgmd — The NDB Cluster Management Server Daemon”
</a>
, describes
other options for
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
.
</p>
<p>
The following files are created or used by
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
in its starting directory, and are
placed in the
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-datadir">
<code class="literal">
DataDir
</code>
</a>
as
specified in the
<code class="filename">
config.ini
</code>
configuration
file. In the list that follows,
<em class="replaceable">
<code>
node_id
</code>
</em>
is the unique node
identifier.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="indexterm" name="idm46045106453648">
</a>
<a class="indexterm" name="idm46045106452160">
</a>
<a class="indexterm" name="idm46045106451088">
</a>
<code class="filename">
config.ini
</code>
is the configuration file
for the cluster as a whole. This file is created by the user
and read by the management server.
<a class="xref" href="mysql-cluster-configuration.html" title="25.4 Configuration of NDB Cluster">
Section 25.4, “Configuration of NDB Cluster”
</a>
, discusses how
to set up this file.
</p>
</li>
<li class="listitem">
<p>
<code class="filename">
ndb_
<em class="replaceable">
<code>
node_id
</code>
</em>
_cluster.log
</code>
is the cluster events log file. Examples of such events
include checkpoint startup and completion, node startup
events, node failures, and levels of memory usage. A
complete listing of cluster events with descriptions may be
found in
<a class="xref" href="mysql-cluster-management.html" title="25.6 Management of NDB Cluster">
Section 25.6, “Management of NDB Cluster”
</a>
.
</p>
<p>
By default, when the size of the cluster log reaches one
million bytes, the file is renamed to
<code class="filename">
ndb_
<em class="replaceable">
<code>
node_id
</code>
</em>
_cluster.log.
<em class="replaceable">
<code>
seq_id
</code>
</em>
</code>
,
where
<em class="replaceable">
<code>
seq_id
</code>
</em>
is the sequence
number of the cluster log file. (For example: If files with
the sequence numbers 1, 2, and 3 already exist, the next log
file is named using the number
<code class="literal">
4
</code>
.) You
can change the size and number of files, and other
characteristics of the cluster log, using the
<a class="link" href="mysql-cluster-mgm-definition.html#ndbparam-mgmd-logdestination">
<code class="literal">
LogDestination
</code>
</a>
configuration parameter.
</p>
</li>
<li class="listitem">
<p>
<code class="filename">
ndb_
<em class="replaceable">
<code>
node_id
</code>
</em>
_out.log
</code>
is the file used for
<code class="literal">
stdout
</code>
and
<code class="literal">
stderr
</code>
when running the management server
as a daemon.
</p>
</li>
<li class="listitem">
<p>
<code class="filename">
ndb_
<em class="replaceable">
<code>
node_id
</code>
</em>
.pid
</code>
is the process ID file used when running the management
server as a daemon.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/information-schema-connection-control-table-reference.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="information-schema-connection-control-table-reference">
</a>
28.6.1 INFORMATION_SCHEMA Connection-Control Table Reference
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045076017312">
</a>
<a class="indexterm" name="idm46045076015808">
</a>
<p>
The following table summarizes
<code class="literal">
INFORMATION_SCHEMA
</code>
connection-control tables.
For greater detail, see the individual table descriptions.
</p>
<div class="table">
<a name="idm46045076013056">
</a>
<p class="title">
<b>
Table 28.8 INFORMATION_SCHEMA Connection-Control
Tables
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="A reference that lists INFORMATION_SCHEMA connection-control tables.">
<colgroup>
<col style="width: 28%"/>
<col style="width: 71%"/>
</colgroup>
<thead>
<tr>
<th>
Table Name
</th>
<th>
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<a class="link" href="information-schema-connection-control-failed-login-attempts-table.html" title="28.6.2 The INFORMATION_SCHEMA CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS Table">
<code class="literal">
CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS
</code>
</a>
</td>
<td>
Current number of consecutive failed connection attempts per account
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/create-table-files.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="create-table-files">
</a>
15.1.20.1 Files Created by CREATE TABLE
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045185422000">
</a>
<a class="indexterm" name="idm46045185420544">
</a>
<a class="indexterm" name="idm46045185419472">
</a>
<a class="indexterm" name="idm46045185418400">
</a>
<a class="indexterm" name="idm46045185417328">
</a>
<p>
For an
<code class="literal">
InnoDB
</code>
table created in a
file-per-table tablespace or general tablespace, table data and
associated indexes are stored in a
<a class="link" href="glossary.html#glos_ibd_file" title=".ibd file">
.ibd file
</a>
in the database
directory. When an
<code class="literal">
InnoDB
</code>
table is created in
the system tablespace, table data and indexes are stored in the
<a class="link" href="glossary.html#glos_ibdata_file" title="ibdata file">
ibdata* files
</a>
that
represent the system tablespace. The
<a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
<code class="literal">
innodb_file_per_table
</code>
</a>
option
controls whether tables are created in file-per-table
tablespaces or the system tablespace, by default. The
<code class="literal">
TABLESPACE
</code>
option can be used to place a
table in a file-per-table tablespace, general tablespace, or the
system tablespace, regardless of the
<a class="link" href="innodb-parameters.html#sysvar_innodb_file_per_table">
<code class="literal">
innodb_file_per_table
</code>
</a>
setting.
</p>
<p>
For
<code class="literal">
MyISAM
</code>
tables, the storage engine creates
data and index files. Thus, for each
<code class="literal">
MyISAM
</code>
table
<em class="replaceable">
<code>
tbl_name
</code>
</em>
, there are two disk
files.
</p>
<div class="informaltable">
<table summary="The purpose of MyISAM table tbl_name disk files.">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<thead>
<tr>
<th>
File
</th>
<th>
Purpose
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
tbl_name
</code>
</em>
.MYD
</code>
</td>
<td>
Data file
</td>
</tr>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
tbl_name
</code>
</em>
.MYI
</code>
</td>
<td>
Index file
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="xref" href="storage-engines.html" title="Chapter 18 Alternative Storage Engines">
Chapter 18,
<i>
Alternative Storage Engines
</i>
</a>
, describes what files each
storage engine creates to represent tables. If a table name
contains special characters, the names for the table files
contain encoded versions of those characters as described in
<a class="xref" href="identifier-mapping.html" title="11.2.4 Mapping of Identifiers to File Names">
Section 11.2.4, “Mapping of Identifiers to File Names”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/show-open-tables.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="show-open-tables">
</a>
15.7.7.25 SHOW OPEN TABLES Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045170100480">
</a>
<a class="indexterm" name="idm46045170098608">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa34400816"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">OPEN</span> <span class="token keyword">TABLES</span>
<span class="token punctuation">[</span>{<span class="token keyword">FROM</span> <span class="token operator">|</span> <span class="token keyword">IN</span>} <em class="replaceable">db_name</em><span class="token punctuation">]</span>
<span class="token punctuation">[</span><span class="token operator">LIKE</span> <span class="token string">'<em class="replaceable">pattern</em>'</span> <span class="token operator">|</span> <span class="token keyword">WHERE</span> <em class="replaceable">expr</em><span class="token punctuation">]</span></code></pre>
</div>
<p>
<a class="link" href="show-open-tables.html" title="15.7.7.25 SHOW OPEN TABLES Statement">
<code class="literal">
SHOW OPEN TABLES
</code>
</a>
lists the
non-
<code class="literal">
TEMPORARY
</code>
tables that are currently open
in the table cache. See
<a class="xref" href="table-cache.html" title="10.4.3.1 How MySQL Opens and Closes Tables">
Section 10.4.3.1, “How MySQL Opens and Closes Tables”
</a>
. The
<code class="literal">
FROM
</code>
clause, if present, restricts the tables
shown to those present in the
<em class="replaceable">
<code>
db_name
</code>
</em>
database. The
<a class="link" href="string-comparison-functions.html#operator_like">
<code class="literal">
LIKE
</code>
</a>
clause, if
present, indicates which table names to match. The
<code class="literal">
WHERE
</code>
clause can be given to select rows
using more general conditions, as discussed in
<a class="xref" href="extended-show.html" title="28.8 Extensions to SHOW Statements">
Section 28.8, “Extensions to SHOW Statements”
</a>
.
</p>
<p>
<a class="link" href="show-open-tables.html" title="15.7.7.25 SHOW OPEN TABLES Statement">
<code class="literal">
SHOW OPEN TABLES
</code>
</a>
output has these
columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Database
</code>
</p>
<p>
The database containing the table.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Table
</code>
</p>
<p>
The table name.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
In_use
</code>
</p>
<p>
The number of table locks or lock requests there are for the
table. For example, if one client acquires a lock for a
table using
<code class="literal">
LOCK TABLE t1 WRITE
</code>
,
<code class="literal">
In_use
</code>
is 1. If another client issues
<code class="literal">
LOCK TABLE t1 WRITE
</code>
while the table
remains locked, the client blocks, waiting for the lock, but
the lock request causes
<code class="literal">
In_use
</code>
to be 2.
If the count is zero, the table is open but not currently
being used.
<code class="literal">
In_use
</code>
is also increased by
the
<a class="link" href="handler.html" title="15.2.5 HANDLER Statement">
<code class="literal">
HANDLER ...
OPEN
</code>
</a>
statement and decreased by
<a class="link" href="handler.html" title="15.2.5 HANDLER Statement">
<code class="literal">
HANDLER ...
CLOSE
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Name_locked
</code>
</p>
<p>
Whether the table name is locked. Name locking is used for
operations such as dropping or renaming tables.
</p>
</li>
</ul>
</div>
<p>
If you have no privileges for a table, it does not show up in
the output from
<a class="link" href="show-open-tables.html" title="15.7.7.25 SHOW OPEN TABLES Statement">
<code class="literal">
SHOW OPEN TABLES
</code>
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/charset-unicode.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="charset-unicode">
</a>
12.9 Unicode Support
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="charset-unicode-utf8mb4.html">
12.9.1 The utf8mb4 Character Set (4-Byte UTF-8 Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-utf8mb3.html">
12.9.2 The utf8mb3 Character Set (3-Byte UTF-8 Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-utf8.html">
12.9.3 The utf8 Character Set (Deprecated alias for utf8mb3)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-ucs2.html">
12.9.4 The ucs2 Character Set (UCS-2 Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-utf16.html">
12.9.5 The utf16 Character Set (UTF-16 Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-utf16le.html">
12.9.6 The utf16le Character Set (UTF-16LE Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-utf32.html">
12.9.7 The utf32 Character Set (UTF-32 Unicode Encoding)
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="charset-unicode-conversion.html">
12.9.8 Converting Between 3-Byte and 4-Byte Unicode Character Sets
</a>
</span>
</dt>
</dl>
</div>
<p>
The Unicode Standard includes characters from the Basic
Multilingual Plane (BMP) and supplementary characters that lie
outside the BMP. This section describes support for Unicode in
MySQL. For information about the Unicode Standard itself, visit
the
<a class="ulink" href="http://www.unicode.org/" target="_blank">
Unicode Consortium
website
</a>
.
</p>
<p>
BMP characters have these characteristics:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Their code point values are between 0 and 65535 (or
<code class="literal">
U+0000
</code>
and
<code class="literal">
U+FFFF
</code>
).
</p>
</li>
<li class="listitem">
<p>
They can be encoded in a variable-length encoding using 8, 16,
or 24 bits (1 to 3 bytes).
</p>
</li>
<li class="listitem">
<p>
They can be encoded in a fixed-length encoding using 16 bits
(2 bytes).
</p>
</li>
<li class="listitem">
<p>
They are sufficient for almost all characters in major
languages.
</p>
</li>
</ul>
</div>
<p>
Supplementary characters lie outside the BMP:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Their code point values are between
<code class="literal">
U+10000
</code>
and
<code class="literal">
U+10FFFF
</code>
).
</p>
</li>
<li class="listitem">
<p>
Unicode support for supplementary characters requires
character sets that have a range outside BMP characters and
therefore take more space than BMP characters (up to 4 bytes
per character).
</p>
</li>
</ul>
</div>
<p>
The UTF-8 (Unicode Transformation Format with 8-bit units) method
for encoding Unicode data is implemented according to RFC 3629,
which describes encoding sequences that take from one to four
bytes. The idea of UTF-8 is that various Unicode characters are
encoded using byte sequences of different lengths:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Basic Latin letters, digits, and punctuation signs use one
byte.
</p>
</li>
<li class="listitem">
<p>
Most European and Middle East script letters fit into a 2-byte
sequence: extended Latin letters (with tilde, macron, acute,
grave and other accents), Cyrillic, Greek, Armenian, Hebrew,
Arabic, Syriac, and others.
</p>
</li>
<li class="listitem">
<p>
Korean, Chinese, and Japanese ideographs use 3-byte or 4-byte
sequences.
</p>
</li>
</ul>
</div>
<p>
MySQL supports these Unicode character sets:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
utf8mb4
</code>
: A UTF-8 encoding of the Unicode
character set using one to four bytes per character.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf8mb3
</code>
: A UTF-8 encoding of the Unicode
character set using one to three bytes per character. This
character set is deprecated andsubject to removal in a future
release; use
<code class="literal">
utf8mb4
</code>
instead.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf8
</code>
: A deprecated alias for
<code class="literal">
utf8mb3
</code>
; use
<code class="literal">
utf8mb4
</code>
instead.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<code class="literal">
utf8
</code>
is expected in a future version of
MySQL to become an alias for
<code class="literal">
utf8mb4
</code>
.
</p>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
ucs2
</code>
: The UCS-2 encoding of the Unicode
character set using two bytes per character. Deprecated;
expect support for this character set to be removed in a
future release.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf16
</code>
: The UTF-16 encoding for the Unicode
character set using two or four bytes per character. Like
<code class="literal">
ucs2
</code>
but with an extension for
supplementary characters.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf16le
</code>
: The UTF-16LE encoding for the
Unicode character set. Like
<code class="literal">
utf16
</code>
but
little-endian rather than big-endian.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf32
</code>
: The UTF-32 encoding for the Unicode
character set using four bytes per character.
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The
<code class="literal">
utf8mb3
</code>
character set is deprecated and
you should expect it to be removed in a future MySQL release.
Please use
<code class="literal">
utf8mb4
</code>
instead.
<code class="literal">
utf8
</code>
is currently an alias for
<code class="literal">
utf8mb3
</code>
, but it is now deprecated as such,
and
<code class="literal">
utf8
</code>
is expected subsequently to become a
reference to
<code class="literal">
utf8mb4
</code>
. MySQL 8.4
also displays
<code class="literal">
utf8mb3
</code>
in place of
<code class="literal">
utf8
</code>
in the columns of Information Schema
tables, and in the output of SQL
<code class="literal">
SHOW
</code>
statements.
</p>
<p>
In addition, you should be aware that collations using the
<code class="literal">
utf8_
</code>
prefix in older releases of MySQL have
since been renamed using the prefix
<code class="literal">
utf8mb3_
</code>
,
instead.
</p>
<p>
To avoid ambiguity about the meaning of
<code class="literal">
utf8
</code>
,
consider specifying
<code class="literal">
utf8mb4
</code>
explicitly for
character set references.
</p>
</div>
<p>
<a class="xref" href="charset-unicode.html#charset-unicode-charset-characteristics" title="Table 12.2 Unicode Character Set General Characteristics">
Table 12.2, “Unicode Character Set General Characteristics”
</a>
,
summarizes the general characteristics of Unicode character sets
supported by MySQL.
</p>
<div class="table">
<a name="charset-unicode-charset-characteristics">
</a>
<p class="title">
<b>
Table 12.2 Unicode Character Set General Characteristics
</b>
</p>
<div class="table-contents">
<table summary="General characteristics of Unicode character sets.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 40%"/>
<col style="width: 40%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Character Set
</th>
<th scope="col">
Supported Characters
</th>
<th scope="col">
Required Storage Per Character
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<code class="literal">
utf8mb3
</code>
,
<code class="literal">
utf8
</code>
(deprecated)
</th>
<td>
BMP only
</td>
<td>
1, 2, or 3 bytes
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
ucs2
</code>
</th>
<td>
BMP only
</td>
<td>
2 bytes
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
utf8mb4
</code>
</th>
<td>
BMP and supplementary
</td>
<td>
1, 2, 3, or 4 bytes
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
utf16
</code>
</th>
<td>
BMP and supplementary
</td>
<td>
2 or 4 bytes
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
utf16le
</code>
</th>
<td>
BMP and supplementary
</td>
<td>
2 or 4 bytes
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
utf32
</code>
</th>
<td>
BMP and supplementary
</td>
<td>
4 bytes
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
Characters outside the BMP compare as
<code class="literal">
REPLACEMENT
CHARACTER
</code>
and convert to
<code class="literal">
'?'
</code>
when
converted to a Unicode character set that supports only BMP
characters (
<code class="literal">
utf8mb3
</code>
or
<code class="literal">
ucs2
</code>
).
</p>
<p>
If you use character sets that support supplementary characters
and thus are
<span class="quote">
“
<span class="quote">
wider
</span>
”
</span>
than the BMP-only
<code class="literal">
utf8mb3
</code>
and
<code class="literal">
ucs2
</code>
character
sets, there are potential incompatibility issues for your
applications; see
<a class="xref" href="charset-unicode-conversion.html" title="12.9.8 Converting Between 3-Byte and 4-Byte Unicode Character Sets">
Section 12.9.8, “Converting Between 3-Byte and 4-Byte Unicode Character Sets”
</a>
.
That section also describes how to convert tables from the
(3-byte)
<code class="literal">
utf8mb3
</code>
to the (4-byte)
<code class="literal">
utf8mb4
</code>
, and what constraints may apply in
doing so.
</p>
<p>
A similar set of collations is available for most Unicode
character sets. For example, each has a Danish collation, the
names of which are
<code class="literal">
utf8mb4_danish_ci
</code>
,
<code class="literal">
utf8mb3_danish_ci
</code>
(deprecated),
<code class="literal">
utf8_danish_ci
</code>
(deprecated),
<code class="literal">
ucs2_danish_ci
</code>
,
<code class="literal">
utf16_danish_ci
</code>
, and
<code class="literal">
utf32_danish_ci
</code>
. The exception is
<code class="literal">
utf16le
</code>
, which has only two collations. For
information about Unicode collations and their differentiating
properties, including collation properties for supplementary
characters, see
<a class="xref" href="charset-unicode-sets.html" title="12.10.1 Unicode Character Sets">
Section 12.10.1, “Unicode Character Sets”
</a>
.
</p>
<p>
The MySQL implementation of UCS-2, UTF-16, and UTF-32 stores
characters in big-endian byte order and does not use a byte order
mark (BOM) at the beginning of values. Other database systems
might use little-endian byte order or a BOM. In such cases,
conversion of values needs to be performed when transferring data
between those systems and MySQL. The implementation of UTF-16LE is
little-endian.
</p>
<p>
MySQL uses no BOM for UTF-8 values.
</p>
<p>
Client applications that communicate with the server using Unicode
should set the client character set accordingly (for example, by
issuing a
<code class="literal">
SET NAMES 'utf8mb4'
</code>
statement). Some
character sets cannot be used as the client character set.
Attempting to use them with
<a class="link" href="set-names.html" title="15.7.6.3 SET NAMES Statement">
<code class="literal">
SET
NAMES
</code>
</a>
or
<a class="link" href="set-character-set.html" title="15.7.6.2 SET CHARACTER SET Statement">
<code class="literal">
SET CHARACTER
SET
</code>
</a>
produces an error. See
<a class="xref" href="charset-connection.html#charset-connection-impermissible-client-charset" title="Impermissible Client Character Sets">
Impermissible Client Character Sets
</a>
.
</p>
<p>
The following sections provide additional detail on the Unicode
character sets in MySQL.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/ansi-diff-select-into-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="ansi-diff-select-into-table">
</a>
1.7.2.1 SELECT INTO TABLE Differences
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045333276016">
</a>
<p>
MySQL Server doesn't support the
<code class="literal">
SELECT ... INTO
TABLE
</code>
Sybase SQL extension. Instead, MySQL Server
supports the
<a class="link" href="insert-select.html" title="15.2.7.1 INSERT ... SELECT Statement">
<code class="literal">
INSERT INTO ...
SELECT
</code>
</a>
standard SQL syntax, which is basically the
same thing. See
<a class="xref" href="insert-select.html" title="15.2.7.1 INSERT ... SELECT Statement">
Section 15.2.7.1, “INSERT ... SELECT Statement”
</a>
. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa99774103"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> tbl_temp2 <span class="token punctuation">(</span>fld_id<span class="token punctuation">)</span>
<span class="token keyword">SELECT</span> tbl_temp1<span class="token punctuation">.</span>fld_order_id
<span class="token keyword">FROM</span> tbl_temp1 <span class="token keyword">WHERE</span> tbl_temp1<span class="token punctuation">.</span>fld_order_id <span class="token operator">></span> <span class="token number">100</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Alternatively, you can use
<a class="link" href="select-into.html" title="15.2.13.1 SELECT ... INTO Statement">
<code class="literal">
SELECT ... INTO
OUTFILE
</code>
</a>
or
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE ...
SELECT
</code>
</a>
.
</p>
<p>
You can use
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT ...
INTO
</code>
</a>
with user-defined variables. The same syntax
can also be used inside stored routines using cursors and
local variables. See
<a class="xref" href="select-into.html" title="15.2.13.1 SELECT ... INTO Statement">
Section 15.2.13.1, “SELECT ... INTO Statement”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/programs-development.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="programs-development">
</a>
6.7 Program Development Utilities
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="mysql-config.html">
6.7.1 mysql_config — Display Options for Compiling Clients
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="my-print-defaults.html">
6.7.2 my_print_defaults — Display Options from Option Files
</a>
</span>
</dt>
</dl>
</div>
<p>
This section describes some utilities that you may find useful when
developing MySQL programs.
</p>
<p>
In shell scripts, you can use the
<a class="link" href="my-print-defaults.html" title="6.7.2 my_print_defaults — Display Options from Option Files">
<span class="command">
<strong>
my_print_defaults
</strong>
</span>
</a>
program to parse option files
and see what options would be used by a given program. The following
example shows the output that
<a class="link" href="my-print-defaults.html" title="6.7.2 my_print_defaults — Display Options from Option Files">
<span class="command">
<strong>
my_print_defaults
</strong>
</span>
</a>
might produce when asked to show the options found in the
<code class="literal">
[client]
</code>
and
<code class="literal">
[mysql]
</code>
groups:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa34582114"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">my_print_defaults</span> client mysql
<span class="token constant">--port</span><span class="token attr-value"><span class="token punctuation">=</span>3306</span>
<span class="token constant">--socket</span><span class="token attr-value"><span class="token punctuation">=</span>/tmp/mysql.sock</span>
<span class="token property">--no-auto-rehash</span></code></pre>
</div>
<p>
Note for developers: Option file handling is implemented in the C
client library simply by processing all options in the appropriate
group or groups before any command-line arguments. This works well
for programs that use the last instance of an option that is
specified multiple times. If you have a C or C++ program that
handles multiply specified options this way but that doesn't read
option files, you need add only two lines to give it that
capability. Check the source code of any of the standard MySQL
clients to see how to do this.
</p>
<p>
Several other language interfaces to MySQL are based on the C client
library, and some of them provide a way to access option file
contents. These include Perl and Python. For details, see the
documentation for your preferred interface.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-features-directory.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-features-directory">
</a>
19.5.1.10 Replication and DIRECTORY Table Options
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045135657568">
</a>
<a class="indexterm" name="idm46045135656080">
</a>
<a class="indexterm" name="idm46045135654592">
</a>
<a class="indexterm" name="idm46045135653104">
</a>
<a class="indexterm" name="idm46045135651616">
</a>
<p>
If a
<code class="literal">
DATA DIRECTORY
</code>
or
<code class="literal">
INDEX
DIRECTORY
</code>
table option is used in a
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statement on the
source server, the table option is also used on the replica.
This can cause problems if no corresponding directory exists in
the replica host file system or if it exists but is not
accessible to the replica MySQL server. This can be overridden
by using the
<a class="link" href="sql-mode.html#sqlmode_no_dir_in_create">
<code class="literal">
NO_DIR_IN_CREATE
</code>
</a>
server SQL mode on the replica, which causes the replica to
ignore the
<code class="literal">
DATA DIRECTORY
</code>
and
<code class="literal">
INDEX
DIRECTORY
</code>
table options when replicating
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
statements. The
result is that
<code class="literal">
MyISAM
</code>
data and index files
are created in the table's database directory.
</p>
<p>
For more information, see
<a class="xref" href="sql-mode.html" title="7.1.11 Server SQL Modes">
Section 7.1.11, “Server SQL Modes”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/stop-replica.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="stop-replica">
</a>
15.4.2.5 STOP REPLICA Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045176922928">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa88269947"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">STOP</span> <span class="token keyword">REPLICA</span> <span class="token punctuation">[</span><em class="replaceable">thread_types</em><span class="token punctuation">]</span> <span class="token punctuation">[</span><em class="replaceable">channel_option</em><span class="token punctuation">]</span>
<em class="replaceable">thread_types</em>:
<span class="token punctuation">[</span><em class="replaceable">thread_type</em> <span class="token punctuation">[</span><span class="token punctuation">,</span> <em class="replaceable">thread_type</em><span class="token punctuation">]</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> <span class="token punctuation">]</span>
<em class="replaceable">thread_type</em>: <span class="token keyword">IO_THREAD</span> <span class="token operator">|</span> <span class="token keyword">SQL_THREAD</span>
<em class="replaceable">channel_option</em>:
<span class="token keyword">FOR</span> <span class="token keyword">CHANNEL</span> <span class="token keyword"><em class="replaceable">channel</em></span></code></pre>
</div>
<p>
Stops the replication threads.
</p>
<p>
<code class="literal">
STOP REPLICA
</code>
requires the
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
privilege
(or the deprecated
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege). Recommended best practice is to execute
<code class="literal">
STOP REPLICA
</code>
on the replica before stopping
the replica server (see
<a class="xref" href="server-shutdown.html" title="7.1.19 The Server Shutdown Process">
Section 7.1.19, “The Server Shutdown Process”
</a>
, for
more information).
</p>
<p>
Like
<a class="link" href="start-replica.html" title="15.4.2.4 START REPLICA Statement">
<code class="literal">
START REPLICA
</code>
</a>
, this
statement may be used with the
<code class="literal">
IO_THREAD
</code>
and
<code class="literal">
SQL_THREAD
</code>
options to name the replication
thread or threads to be stopped. Note that the Group Replication
applier channel (
<code class="literal">
group_replication_applier
</code>
)
has no replication I/O (receiver) thread, only a replication SQL
(applier) thread. Using the
<code class="literal">
SQL_THREAD
</code>
option
therefore stops this channel completely.
</p>
<p>
<code class="literal">
STOP REPLICA
</code>
causes an implicit commit of an
ongoing transaction. See
<a class="xref" href="implicit-commit.html" title="15.3.3 Statements That Cause an Implicit Commit">
Section 15.3.3, “Statements That Cause an Implicit Commit”
</a>
.
</p>
<p>
<a class="link" href="replication-options-gtids.html#sysvar_gtid_next">
<code class="literal">
gtid_next
</code>
</a>
must be set to
<code class="literal">
AUTOMATIC
</code>
before issuing this statement.
</p>
<p>
You can control how long
<code class="literal">
STOP REPLICA
</code>
waits
before timing out by setting the system variable
<a class="link" href="replication-options-replica.html#sysvar_rpl_stop_replica_timeout">
<code class="literal">
rpl_stop_replica_timeout
</code>
</a>
. This
can be used to avoid deadlocks between
<code class="literal">
STOP
REPLICA
</code>
and other SQL statements using different
client connections to the replica. When the timeout value is
reached, the issuing client returns an error message and stops
waiting, but the
<code class="literal">
STOP REPLICA
</code>
instruction
remains in effect. Once the replication threads are no longer
busy, the
<code class="literal">
STOP REPLICA
</code>
statement is executed
and the replica stops.
</p>
<p>
Some
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE TO
</code>
</a>
statements are allowed while the replica is running, depending
on the states of the replication threads. However, using
<code class="literal">
STOP REPLICA
</code>
prior to executing a
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE TO
</code>
</a>
statement in such cases is still supported. See
<a class="xref" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
Section 15.4.2.2, “CHANGE REPLICATION SOURCE TO Statement”
</a>
, and
<a class="xref" href="replication-solutions-switch.html" title="19.4.8 Switching Sources During Failover">
Section 19.4.8, “Switching Sources During Failover”
</a>
, for more
information.
</p>
<p>
The optional
<code class="literal">
FOR CHANNEL
<em class="replaceable">
<code>
channel
</code>
</em>
</code>
clause enables you
to name which replication channel the statement applies to.
Providing a
<code class="literal">
FOR CHANNEL
<em class="replaceable">
<code>
channel
</code>
</em>
</code>
clause applies the
<code class="literal">
STOP REPLICA
</code>
statement to a specific
replication channel. If no channel is named and no extra
channels exist, the statement applies to the default channel. If
a
<code class="literal">
STOP REPLICA
</code>
statement does not name a
channel when using multiple channels, this statement stops the
specified threads for all channels. See
<a class="xref" href="replication-channels.html" title="19.2.2 Replication Channels">
Section 19.2.2, “Replication Channels”
</a>
for more
information.
</p>
<p>
The replication channels for Group Replication
(
<code class="literal">
group_replication_applier
</code>
and
<code class="literal">
group_replication_recovery
</code>
) are managed
automatically by the server instance.
<code class="literal">
STOP
REPLICA
</code>
cannot be used at all with the
<code class="literal">
group_replication_recovery
</code>
channel, and
should only be used with the
<code class="literal">
group_replication_applier
</code>
channel when Group
Replication is not running. The
<code class="literal">
group_replication_applier
</code>
channel only has an
applier thread and has no receiver thread, so it can be stopped
if required by using the
<code class="literal">
SQL_THREAD
</code>
option
without the
<code class="literal">
IO_THREAD
</code>
option.
</p>
<p>
When the replica is multithreaded
(
<a class="link" href="replication-options-replica.html#sysvar_replica_parallel_workers">
<code class="literal">
replica_parallel_workers
</code>
</a>
is a
nonzero value), any gaps in the sequence of transactions
executed from the relay log are closed as part of stopping the
worker threads. If the replica is stopped unexpectedly (for
example due to an error in a worker thread, or another thread
issuing
<a class="link" href="kill.html" title="15.7.8.4 KILL Statement">
<code class="literal">
KILL
</code>
</a>
) while a
<code class="literal">
STOP REPLICA
</code>
statement is executing, the
sequence of executed transactions from the relay log may become
inconsistent. See
<a class="xref" href="replication-features-transaction-inconsistencies.html" title="19.5.1.34 Replication and Transaction Inconsistencies">
Section 19.5.1.34, “Replication and Transaction Inconsistencies”
</a>
,
for more information.
</p>
<p>
When the source is using the row-based binary logging format,
you should execute
<code class="literal">
STOP REPLICA
</code>
or
<code class="literal">
STOP REPLICA SQL_THREAD
</code>
on the replica prior
to shutting down the replica server if you are replicating any
tables that use a nontransactional storage engine. If the
current replication event group has modified one or more
nontransactional tables,
<code class="literal">
STOP REPLICA
</code>
waits
for up to 60 seconds for the event group to complete, unless you
issue a
<a class="link" href="kill.html" title="15.7.8.4 KILL Statement">
<code class="literal">
KILL
QUERY
</code>
</a>
or
<a class="link" href="kill.html" title="15.7.8.4 KILL Statement">
<code class="literal">
KILL
CONNECTION
</code>
</a>
statement for the replication SQL thread.
If the event group remains incomplete after the timeout, an
error message is logged.
</p>
<p>
When the source is using the statement-based binary logging
format, changing the source while it has open temporary tables
is potentially unsafe. This is one of the reasons why
statement-based replication of temporary tables is not
recommended. You can find out whether there are any temporary
tables on the replica by checking the value of
<a class="link" href="server-status-variables.html#statvar_Replica_open_temp_tables">
<code class="literal">
Replica_open_temp_tables
</code>
</a>
. When
using statement-based replication, this value should be 0 before
executing
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE
TO
</code>
</a>
. If there are any temporary tables open on the
replica, issuing a
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION
SOURCE TO
</code>
</a>
statement after issuing a
<code class="literal">
STOP
REPLICA
</code>
causes an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_warn_open_temp_tables_must_be_zero" target="_top">
<code class="literal">
ER_WARN_OPEN_TEMP_TABLES_MUST_BE_ZERO
</code>
</a>
warning.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/group-replication-configuring-online-group.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="group-replication-configuring-online-group">
</a>
20.5.1 Configuring an Online Group
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="group-replication-change-primary.html">
20.5.1.1 Changing the Primary
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="group-replication-changing-group-mode.html">
20.5.1.2 Changing the Group Mode
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="group-replication-group-write-consensus.html">
20.5.1.3 Using Group Replication Group Write Consensus
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="group-replication-communication-protocol.html">
20.5.1.4 Setting a Group's Communication Protocol Version
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="group-replication-member-actions.html">
20.5.1.5 Configuring Member Actions
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045133622256">
</a>
<a class="indexterm" name="idm46045133620752">
</a>
<p>
You can configure an online group while Group Replication is
running by using a set of functions, which rely on a group action
coordinator. These functions are installed by the Group
Replication plugin. This section describes how changes are made to
a running group, and the available functions.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
For the coordinator to be able to configure group wide actions
on a running group, all members must have the functions
installed.
</p>
</div>
<p>
To use the functions, connect to a member of the running group and
invoke the function with the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement. The Group Replication plugin processes the action and
its parameters and the coordinator sends it to all members which
are visible to the member where you invoked the function. If the
action is accepted, all members execute the action and send a
termination message when completed. Once all members declare the
action as finished, the invoking member returns the result to the
client.
</p>
<p>
When configuring a whole group, the distributed nature of the
operations means that they interact with many processes of the
Group Replication plugin, and therefore you should observe the
following:
</p>
<p>
<b>
You can issue configuration operations everywhere.
</b>
If you want to make member A the new primary you do not need to
invoke the operation on member A. All operations are sent and
executed in a coordinated way on all group members. Also, this
distributed execution of an operation has a different
ramification: if the invoking member dies, any already running
configuration process continues to run on other members. In the
unlikely event that the invoking member dies, you can still use
the monitoring features to ensure other members complete the
operation successfully.
</p>
<p>
<b>
All members must be online.
</b>
To simplify the migration or election processes and guarantee
they are as fast as possible, the group must not contain any
member currently in the distributed recovery process, otherwise
the configuration action is rejected by the member where you
issue the statement.
</p>
<p>
<b>
No members can join a group during a configuration change.
</b>
Any member that attempts to join the group during a coordinated
configuration change leaves the group and cancels its join
process.
</p>
<p>
<b>
Only one configuration at once.
</b>
A group which is executing a configuration change cannot accept
any other group configuration change, because concurrent
configuration operations could lead to member divergence.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-index-stat.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-programs-ndb-index-stat">
</a>
25.5.14 ndb_index_stat — NDB Index Statistics Utility
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045101793264">
</a>
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
provides per-fragment
statistical information about indexes on
<code class="literal">
NDB
</code>
tables. This includes cache version and age, number of index
entries per partition, and memory consumption by indexes.
</p>
<h4>
<a name="idm46045101789600">
</a>
Usage
</h4>
<p>
To obtain basic index statistics about a given
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
table, invoke
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
as shown here, with the name
of the table as the first argument and the name of the database
containing this table specified immediately following it, using
the
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_database">
<code class="option">
--database
</code>
</a>
(
<code class="option">
-d
</code>
) option:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa14153968"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">ndb_index_stat <em class="replaceable">table</em> <span class="token property">-d</span> <em class="replaceable">database</em></code></pre>
</div>
<p>
In this example, we use
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
to
obtain such information about an
<code class="literal">
NDB
</code>
table
named
<code class="literal">
mytable
</code>
in the
<code class="literal">
test
</code>
database:
</p>
<a class="indexterm" name="idm46045101778624">
</a>
<a class="indexterm" name="idm46045101777136">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa61085393"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">ndb_index_stat</span> <span class="token property">-d</span> test mytable
table<span class="token punctuation">:</span>City index<span class="token punctuation">:</span>PRIMARY fragCount<span class="token punctuation">:</span>2
sampleVersion<span class="token punctuation">:</span>3 loadTime<span class="token punctuation">:</span>1399585986 sampleCount<span class="token punctuation">:</span>1994 keyBytes<span class="token punctuation">:</span>7976
query cache<span class="token punctuation">:</span> valid<span class="token punctuation">:</span>1 sampleCount<span class="token punctuation">:</span>1994 totalBytes<span class="token punctuation">:</span>27916
times in ms<span class="token punctuation">:</span> save<span class="token punctuation">:</span> 7<span class="token punctuation">.</span>133 sort<span class="token punctuation">:</span> 1<span class="token punctuation">.</span>974 sort per sample<span class="token punctuation">:</span> 0<span class="token punctuation">.</span>000</code></pre>
</div>
<p>
<code class="literal">
sampleVersion
</code>
is the version number of the
cache from which the statistics data is taken. Running
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
with the
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_update">
<code class="option">
--update
</code>
</a>
option causes
sampleVersion to be incremented.
</p>
<p>
<code class="literal">
loadTime
</code>
shows when the cache was last
updated. This is expressed as seconds since the Unix Epoch.
</p>
<p>
<code class="literal">
sampleCount
</code>
is the number of index entries
found per partition. You can estimate the total number of
entries by multiplying this by the number of fragments (shown as
<code class="literal">
fragCount
</code>
).
</p>
<p>
<code class="literal">
sampleCount
</code>
can be compared with the
cardinality of
<a class="link" href="show-index.html" title="15.7.7.23 SHOW INDEX Statement">
<code class="literal">
SHOW INDEX
</code>
</a>
or
<a class="link" href="information-schema-statistics-table.html" title="28.3.34 The INFORMATION_SCHEMA STATISTICS Table">
<code class="literal">
INFORMATION_SCHEMA.STATISTICS
</code>
</a>
,
although the latter two provide a view of the table as a whole,
while
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
provides a per-fragment
average.
</p>
<p>
<code class="literal">
keyBytes
</code>
is the number of bytes used by the
index. In this example, the primary key is an integer, which
requires four bytes for each index, so
<code class="literal">
keyBytes
</code>
can be calculated in this case as
shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa56654575"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple"> keyBytes <span class="token operator">=</span> sampleCount <span class="token operator">*</span> <span class="token punctuation">(</span>4 bytes per index<span class="token punctuation">)</span> <span class="token operator">=</span> 1994 <span class="token operator">*</span> 4 <span class="token operator">=</span> 7976</code></pre>
</div>
<p>
This information can also be obtained using the corresponding
column definitions from
<a class="link" href="information-schema-columns-table.html" title="28.3.8 The INFORMATION_SCHEMA COLUMNS Table">
<code class="literal">
INFORMATION_SCHEMA.COLUMNS
</code>
</a>
(this
requires a MySQL Server and a MySQL client application).
</p>
<p>
<code class="literal">
totalBytes
</code>
is the total memory consumed by
all indexes on the table, in bytes.
</p>
<p>
Timings shown in the preceding examples are specific to each
invocation of
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
.
</p>
<p>
The
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_verbose">
<code class="option">
--verbose
</code>
</a>
option
provides some additional output, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa91359579"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">ndb_index_stat</span> <span class="token property">-d</span> test mytable <span class="token property">--verbose</span>
random seed 1337010518
connected
loop 1 of 1
table<span class="token punctuation">:</span>mytable index<span class="token punctuation">:</span>PRIMARY fragCount<span class="token punctuation">:</span>4
sampleVersion<span class="token punctuation">:</span>2 loadTime<span class="token punctuation">:</span>1336751773 sampleCount<span class="token punctuation">:</span>0 keyBytes<span class="token punctuation">:</span>0
read stats
query cache created
query cache<span class="token punctuation">:</span> valid<span class="token punctuation">:</span>1 sampleCount<span class="token punctuation">:</span>0 totalBytes<span class="token punctuation">:</span>0
times in ms<span class="token punctuation">:</span> save<span class="token punctuation">:</span> 20<span class="token punctuation">.</span>766 sort<span class="token punctuation">:</span> 0<span class="token punctuation">.</span>001
disconnected
$></code></pre>
</div>
<p>
If the output from the program is empty, this may indicate that
no statistics yet exist. To force them to be created (or updated
if they already exist), invoke
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
with the
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_update">
<code class="option">
--update
</code>
</a>
option,
or execute
<a class="link" href="analyze-table.html" title="15.7.3.1 ANALYZE TABLE Statement">
<code class="literal">
ANALYZE TABLE
</code>
</a>
on the
table in the
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
client.
</p>
<h4>
<a name="idm46045101744960">
</a>
Options
</h4>
<p>
The following table includes options that are specific to the
NDB Cluster
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html" title="25.5.14 ndb_index_stat — NDB Index Statistics Utility">
<span class="command">
<strong>
ndb_index_stat
</strong>
</span>
</a>
utility.
Additional descriptions are listed following the table.
</p>
<p>
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="option_ndb_index_stat_character-sets-dir">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_character-sets-dir">
<code class="option">
--character-sets-dir
</code>
</a>
</p>
<a class="indexterm" name="idm46045101739328">
</a>
<a class="indexterm" name="idm46045101737824">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for character-sets-dir">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--character-sets-dir=path
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Directory containing character sets.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_connect-retries">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_connect-retries">
<code class="option">
--connect-retries
</code>
</a>
</p>
<a class="indexterm" name="idm46045101728032">
</a>
<a class="indexterm" name="idm46045101726544">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-retries">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-retries=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Number of times to retry connection before giving up.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_connect-retry-delay">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_connect-retry-delay">
<code class="option">
--connect-retry-delay
</code>
</a>
</p>
<a class="indexterm" name="idm46045101707440">
</a>
<a class="indexterm" name="idm46045101705936">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-retry-delay">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-retry-delay=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
5
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
5
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Number of seconds to wait between attempts to contact
management server.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_connect-string">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_connect-string">
<code class="option">
--connect-string
</code>
</a>
</p>
<a class="indexterm" name="idm46045101686816">
</a>
<a class="indexterm" name="idm46045101685328">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for connect-string">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--connect-string=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Same as
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-connectstring">
<code class="option">
--ndb-connectstring
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_core-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_core-file">
<code class="option">
--core-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045101669968">
</a>
<a class="indexterm" name="idm46045101668480">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for core-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--core-file
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Write core file on error; used in debugging.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_database">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_database">
<code class="option">
--database=
<em class="replaceable">
<code>
name
</code>
</em>
</code>
</a>
,
<code class="option">
-d
<em class="replaceable">
<code>
name
</code>
</em>
</code>
</p>
<a class="indexterm" name="idm46045101657824">
</a>
<a class="indexterm" name="idm46045101656336">
</a>
<a class="indexterm" name="idm46045101654848">
</a>
<a class="indexterm" name="idm46045101653360">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for database">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--database=name
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
The name of the database that contains the table being
queried.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_defaults-extra-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_defaults-extra-file">
<code class="option">
--defaults-extra-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045101634416">
</a>
<a class="indexterm" name="idm46045101632912">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-extra-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-extra-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given file after global files are read.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_defaults-file">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_defaults-file">
<code class="option">
--defaults-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045101618624">
</a>
<a class="indexterm" name="idm46045101617136">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read default options from given file only.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_defaults-group-suffix">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_defaults-group-suffix">
<code class="option">
--defaults-group-suffix
</code>
</a>
</p>
<a class="indexterm" name="idm46045101602848">
</a>
<a class="indexterm" name="idm46045101601344">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-group-suffix">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-group-suffix=string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Also read groups with concat(group, suffix).
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_delete">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_delete">
<code class="option">
--delete
</code>
</a>
</p>
<a class="indexterm" name="idm46045101587056">
</a>
<a class="indexterm" name="idm46045101585568">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for delete">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--delete
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Delete the index statistics for the given table, stopping
any auto-update that was previously configured.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_dump">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_dump">
<code class="option">
--dump
</code>
</a>
</p>
<a class="indexterm" name="idm46045101575792">
</a>
<a class="indexterm" name="idm46045101574304">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for dump">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--dump
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Dump the contents of the query cache.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_help">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_help">
<code class="option">
--help
</code>
</a>
</p>
<a class="indexterm" name="idm46045101564608">
</a>
<a class="indexterm" name="idm46045101563120">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for help">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--help
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display help text and exit.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_login-path">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_login-path">
<code class="option">
--login-path
</code>
</a>
</p>
<a class="indexterm" name="idm46045101553376">
</a>
<a class="indexterm" name="idm46045101551888">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for login-path">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--login-path=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given path from login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_no-login-paths">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_no-login-paths">
<code class="option">
--no-login-paths
</code>
</a>
</p>
<a class="indexterm" name="idm46045101537616">
</a>
<a class="indexterm" name="idm46045101536128">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-login-paths">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-login-paths
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Skips reading options from the login path file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_loops">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_loops">
<code class="option">
--loops=
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045101526096">
</a>
<a class="indexterm" name="idm46045101524608">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for loops">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--loops=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Numeric
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
MAX_INT
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Repeat commands this number of times (for use in testing).
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-connectstring">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-connectstring">
<code class="option">
--ndb-connectstring
</code>
</a>
</p>
<a class="indexterm" name="idm46045101505680">
</a>
<a class="indexterm" name="idm46045101504224">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-connectstring">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-connectstring=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Set connection string for connecting to
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
. Syntax:
<code class="literal">
[nodeid=
<em class="replaceable">
<code>
id
</code>
</em>
;][host=]
<em class="replaceable">
<code>
hostname
</code>
</em>
[:
<em class="replaceable">
<code>
port
</code>
</em>
]
</code>
.
Overrides entries in
<code class="literal">
NDB_CONNECTSTRING
</code>
and
<code class="filename">
my.cnf
</code>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-mgm-tls">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-mgm-tls">
<code class="option">
--ndb-mgm-tls
</code>
</a>
</p>
<a class="indexterm" name="idm46045101485184">
</a>
<a class="indexterm" name="idm46045101483696">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-mgm-tls">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-mgm-tls=level
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Enumeration
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
relaxed
</code>
</td>
</tr>
<tr>
<th>
Valid Values
</th>
<td>
<p class="valid-value">
<code class="literal">
relaxed
</code>
</p>
<p class="valid-value">
<code class="literal">
strict
</code>
</p>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Sets the level of TLS support required to connect to the
management server; one of
<code class="literal">
relaxed
</code>
or
<code class="literal">
strict
</code>
.
<code class="literal">
relaxed
</code>
(the
default) means that a TLS connection is attempted, but
success is not required;
<code class="literal">
strict
</code>
means
that TLS is required to connect.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-mgmd-host">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-mgmd-host">
<code class="option">
--ndb-mgmd-host
</code>
</a>
</p>
<a class="indexterm" name="idm46045101462576">
</a>
<a class="indexterm" name="idm46045101461088">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-mgmd-host">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-mgmd-host=connection_string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Same as
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-connectstring">
<code class="option">
--ndb-connectstring
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-nodeid">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-nodeid">
<code class="option">
--ndb-nodeid
</code>
</a>
</p>
<a class="indexterm" name="idm46045101445840">
</a>
<a class="indexterm" name="idm46045101444352">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-nodeid">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-nodeid=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Set node ID for this node, overriding any ID set by
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-connectstring">
<code class="option">
--ndb-connectstring
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-optimized-node-selection">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-optimized-node-selection">
<code class="option">
--ndb-optimized-node-selection
</code>
</a>
</p>
<a class="indexterm" name="idm46045101429040">
</a>
<a class="indexterm" name="idm46045101427536">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-optimized-node-selection">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-optimized-node-selection
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Enable optimizations for selection of nodes for
transactions. Enabled by default; use
<code class="option">
--skip-ndb-optimized-node-selection
</code>
to
disable.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_ndb-tls-search-path">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_ndb-tls-search-path">
<code class="option">
--ndb-tls-search-path
</code>
</a>
</p>
<a class="indexterm" name="idm46045101417104">
</a>
<a class="indexterm" name="idm46045101415600">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for ndb-tls-search-path">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--ndb-tls-search-path=list
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Path name
</td>
</tr>
<tr>
<th>
Default Value (Unix)
</th>
<td>
<code class="literal">
$HOME/ndb-tls
</code>
</td>
</tr>
<tr>
<th>
Default Value (Windows)
</th>
<td>
<code class="literal">
$HOMEDIR/ndb-tls
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Specify a list of directories to search for a CA file. On
Unix platforms, the directory names are separated by colons
(
<code class="literal">
:
</code>
); on Windows systems, the semicolon
character (
<code class="literal">
;
</code>
) is used as the separator. A
directory reference may be relative or absolute; it may
contain one or more environment variables, each denoted by a
prefixed dollar sign (
<code class="literal">
$
</code>
), and expanded
prior to use.
</p>
<p>
Searching begins with the leftmost named directory and
proceeds from left to right until a file is found. An empty
string denotes an empty search path, which causes all
searches to fail. A string consisting of a single dot
(
<code class="literal">
.
</code>
) indicates that the search path
limited to the current working directory.
</p>
<p>
If no search path is supplied, the compiled-in default value
is used. This value depends on the platform used: On
Windows, this is
<code class="literal">
\ndb-tls
</code>
; on other
platforms (including Linux), it is
<code class="literal">
$HOME/ndb-tls
</code>
. This can be overridden by
compiling NDB Cluster using
<a class="link" href="source-configuration-options.html#option_cmake_with_ndb_tls_search_path">
<code class="option">
-DWITH_NDB_TLS_SEARCH_PATH
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_no-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_no-defaults">
<code class="option">
--no-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045101391840">
</a>
<a class="indexterm" name="idm46045101390352">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not read default options from any option file other than
login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_print-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_print-defaults">
<code class="option">
--print-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045101380528">
</a>
<a class="indexterm" name="idm46045101379040">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for print-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--print-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Print program argument list and exit.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_query">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_query">
<code class="option">
--query=
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045101369008">
</a>
<a class="indexterm" name="idm46045101367520">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for query">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--query=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Numeric
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
MAX_INT
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Perform random range queries on first key attribute (must be
int unsigned).
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-drop">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-drop">
<code class="option">
--sys-drop
</code>
</a>
</p>
<a class="indexterm" name="idm46045101348320">
</a>
<a class="indexterm" name="idm46045101346832">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-drop">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-drop
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Drop all statistics tables and events in the NDB kernel.
<span class="emphasis">
<em>
This causes all statistics to be lost
</em>
</span>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-create">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create">
<code class="option">
--sys-create
</code>
</a>
</p>
<a class="indexterm" name="idm46045101336528">
</a>
<a class="indexterm" name="idm46045101335040">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-create">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-create
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Create all statistics tables and events in the NDB kernel.
This works only if none of them exist previously.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-create-if-not-exist">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create-if-not-exist">
<code class="option">
--sys-create-if-not-exist
</code>
</a>
</p>
<a class="indexterm" name="idm46045101325088">
</a>
<a class="indexterm" name="idm46045101323584">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-create-if-not-exist">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-create-if-not-exist
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Create any NDB system statistics tables or events (or both)
that do not already exist when the program is invoked.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-create-if-not-valid">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create-if-not-valid">
<code class="option">
--sys-create-if-not-valid
</code>
</a>
</p>
<a class="indexterm" name="idm46045101313616">
</a>
<a class="indexterm" name="idm46045101312112">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-create-if-not-valid">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-create-if-not-valid
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Create any NDB system statistics tables or events that do
not already exist, after dropping any that are invalid.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-check">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-check">
<code class="option">
--sys-check
</code>
</a>
</p>
<a class="indexterm" name="idm46045101302240">
</a>
<a class="indexterm" name="idm46045101300752">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-check">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-check
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Verify that all required system statistics tables and events
exist in the NDB kernel.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-skip-tables">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-skip-tables">
<code class="option">
--sys-skip-tables
</code>
</a>
</p>
<a class="indexterm" name="idm46045101290976">
</a>
<a class="indexterm" name="idm46045101289488">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-skip-tables">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-skip-tables
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not apply any
<code class="option">
--sys-*
</code>
options to any
statistics tables.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_sys-skip-events">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-skip-events">
<code class="option">
--sys-skip-events
</code>
</a>
</p>
<a class="indexterm" name="idm46045101279248">
</a>
<a class="indexterm" name="idm46045101277760">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for sys-skip-events">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--sys-skip-events
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not apply any
<code class="option">
--sys-*
</code>
options to any
events.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_update">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_update">
<code class="option">
--update
</code>
</a>
</p>
<a class="indexterm" name="idm46045101267712">
</a>
<a class="indexterm" name="idm46045101266224">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for update">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--update
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Update the index statistics for the given table, and restart
any auto-update that was previously configured.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_usage">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_usage">
<code class="option">
--usage
</code>
</a>
</p>
<a class="indexterm" name="idm46045101256384">
</a>
<a class="indexterm" name="idm46045101254896">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for usage">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--usage
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display help text and exit; same as
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_help">
<code class="option">
--help
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_verbose">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_verbose">
<code class="option">
--verbose
</code>
</a>
</p>
<a class="indexterm" name="idm46045101244320">
</a>
<a class="indexterm" name="idm46045101242832">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for verbose">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--verbose
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Turn on verbose output.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_index_stat_version">
</a>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_version">
<code class="option">
--version
</code>
</a>
</p>
<a class="indexterm" name="idm46045101233152">
</a>
<a class="indexterm" name="idm46045101231664">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for version">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--version
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Display version information and exit.
</p>
</li>
</ul>
</div>
<p>
<a name="ndb-index-stat-options-system">
</a>
<b>
ndb_index_stat system options.
</b>
The following options are used to generate and update the
statistics tables in the NDB kernel. None of these options can
be mixed with statistics options (see
<a class="xref" href="mysql-cluster-programs-ndb-index-stat.html#ndb-index-stat-options-statistics" title="ndb_index_stat statistics options">
ndb_index_stat statistics options
</a>
).
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-drop">
<code class="option">
--sys-drop
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create">
<code class="option">
--sys-create
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create-if-not-exist">
<code class="option">
--sys-create-if-not-exist
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-create-if-not-valid">
<code class="option">
--sys-create-if-not-valid
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-check">
<code class="option">
--sys-check
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-skip-tables">
<code class="option">
--sys-skip-tables
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_sys-skip-events">
<code class="option">
--sys-skip-events
</code>
</a>
</p>
</li>
</ul>
</div>
<p>
<a name="ndb-index-stat-options-statistics">
</a>
<b>
ndb_index_stat statistics options.
</b>
The options listed here are used to generate index statistics.
They work with a given table and database. They cannot be
mixed with system options (see
<a class="xref" href="mysql-cluster-programs-ndb-index-stat.html#ndb-index-stat-options-system" title="ndb_index_stat system options">
ndb_index_stat system options
</a>
).
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_database">
<code class="option">
--database
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_delete">
<code class="option">
--delete
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_update">
<code class="option">
--update
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_dump">
<code class="option">
--dump
</code>
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="mysql-cluster-programs-ndb-index-stat.html#option_ndb_index_stat_query">
<code class="option">
--query
</code>
</a>
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/error-message-language.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="error-message-language">
</a>
12.12 Setting the Error Message Language
</h2>
</div>
</div>
</div>
<a class="indexterm" name="idm46045215469824">
</a>
<a class="indexterm" name="idm46045215468368">
</a>
<a class="indexterm" name="idm46045215466880">
</a>
<a class="indexterm" name="idm46045215465392">
</a>
<p>
By default,
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
produces error messages in
English, but they can be displayed instead in any of several other
languages: Czech, Danish, Dutch, Estonian, French, German, Greek,
Hungarian, Italian, Japanese, Korean, Norwegian, Norwegian-ny,
Polish, Portuguese, Romanian, Russian, Slovak, Spanish, or
Swedish. This applies to messages the server writes to the error
log and sends to clients.
</p>
<p>
To select the language in which the server writes error messages,
follow the instructions in this section. For information about
changing the character set for error messages (rather than the
language), see
<a class="xref" href="charset-errors.html" title="12.6 Error Message Character Set">
Section 12.6, “Error Message Character Set”
</a>
. For general
information about configuring error logging, see
<a class="xref" href="error-log.html" title="7.4.2 The Error Log">
Section 7.4.2, “The Error Log”
</a>
.
</p>
<p>
The server searches for the error message file using these rules:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
It looks for the file in a directory constructed from two
system variable values,
<a class="link" href="server-system-variables.html#sysvar_lc_messages_dir">
<code class="literal">
lc_messages_dir
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_lc_messages">
<code class="literal">
lc_messages
</code>
</a>
, with the latter
converted to a language name. Suppose that you start the
server using this command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa18031465"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">mysqld <span class="token constant">--lc_messages_dir</span><span class="token attr-value"><span class="token punctuation">=</span>/usr/share/mysql</span> <span class="token constant">--lc_messages</span><span class="token attr-value"><span class="token punctuation">=</span>fr_FR</span></code></pre>
</div>
<p>
In this case,
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
maps the locale
<code class="literal">
fr_FR
</code>
to the language
<code class="literal">
french
</code>
and looks for the error file in the
<code class="filename">
/usr/share/mysql/french
</code>
directory.
</p>
<p>
By default, the language files are located in the
<code class="filename">
share/mysql/
<em class="replaceable">
<code>
LANGUAGE
</code>
</em>
</code>
directory under the MySQL base directory.
</p>
</li>
<li class="listitem">
<p>
If the message file cannot be found in the directory
constructed as just described, the server ignores the
<a class="link" href="server-system-variables.html#sysvar_lc_messages">
<code class="literal">
lc_messages
</code>
</a>
value and uses
only the
<a class="link" href="server-system-variables.html#sysvar_lc_messages_dir">
<code class="literal">
lc_messages_dir
</code>
</a>
value as the location in which to look.
</p>
</li>
<li class="listitem">
<p>
If the server cannot find the configured message file, it
writes a message to the error log to indicate the problem and
defaults to built-in English messages.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_lc_messages_dir">
<code class="literal">
lc_messages_dir
</code>
</a>
system
variable can be set only at server startup and has only a global
read-only value at runtime.
<a class="link" href="server-system-variables.html#sysvar_lc_messages">
<code class="literal">
lc_messages
</code>
</a>
can be set at server
startup and has global and session values that can be modified at
runtime. Thus, the error message language can be changed while the
server is running, and each client can have its own error message
language by setting its session
<a class="link" href="server-system-variables.html#sysvar_lc_messages">
<code class="literal">
lc_messages
</code>
</a>
value to the desired
locale name. For example, if the server is using the
<code class="literal">
fr_FR
</code>
locale for error messages, a client can
execute this statement to receive error messages in English:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa55759459"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> lc_messages <span class="token operator">=</span> <span class="token string">'en_US'</span><span class="token punctuation">;</span></code></pre>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/transport-protocols.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="transport-protocols">
</a>
6.2.7 Connection Transport Protocols
</h3>
</div>
</div>
</div>
<p>
For programs that use the MySQL client library (for example,
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
and
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
), MySQL
supports connections to the server based on several transport
protocols: TCP/IP, Unix socket file, named pipe, and shared
memory. This section describes how to select these protocols, and
how they are similar and different.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="transport-protocols.html#transport-protocol-selection" title="Transport Protocol Selection">
Transport Protocol Selection
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="transport-protocols.html#transport-protocol-local-remote" title="Transport Support for Local and Remote Connections">
Transport Support for Local and Remote Connections
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="transport-protocols.html#transport-protocol-localhost" title="Interpretation of localhost">
Interpretation of localhost
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="transport-protocols.html#transport-protocol-encryption" title="Encryption and Security Characteristics">
Encryption and Security Characteristics
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="transport-protocols.html#transport-protocol-compression" title="Connection Compression">
Connection Compression
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="transport-protocol-selection">
</a>
Transport Protocol Selection
</h4>
</div>
</div>
</div>
<p>
For a given connection, if the transport protocol is not
specified explicitly, it is determined implicitly. For example,
connections to
<code class="literal">
localhost
</code>
result in a socket
file connection on Unix and Unix-like systems, and a TCP/IP
connection to
<code class="literal">
127.0.0.1
</code>
otherwise. For
additional information, see
<a class="xref" href="connecting.html" title="6.2.4 Connecting to the MySQL Server Using Command Options">
Section 6.2.4, “Connecting to the MySQL Server Using Command Options”
</a>
.
</p>
<p>
To specify the protocol explicitly, use the
<a class="link" href="connection-options.html#option_general_protocol">
<code class="option">
--protocol
</code>
</a>
command option. The
following table shows the permissible values for
<a class="link" href="connection-options.html#option_general_protocol">
<code class="option">
--protocol
</code>
</a>
and indicates the
applicable platforms for each value. The values are not
case-sensitive.
</p>
<div class="informaltable">
<table summary="Permissible transport protocol values, the resulting transport protocol used, and the applicable platforms for each value.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 50%"/>
<col style="width: 30%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
<a class="link" href="connection-options.html#option_general_protocol">
<code class="option">
--protocol
</code>
</a>
Value
</th>
<th scope="col">
Transport Protocol Used
</th>
<th scope="col">
Applicable Platforms
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<code class="literal">
TCP
</code>
</th>
<td>
TCP/IP
</td>
<td>
All
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
SOCKET
</code>
</th>
<td>
Unix socket file
</td>
<td>
Unix and Unix-like systems
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
PIPE
</code>
</th>
<td>
Named pipe
</td>
<td>
Windows
</td>
</tr>
<tr>
<th scope="row">
<code class="literal">
MEMORY
</code>
</th>
<td>
Shared memory
</td>
<td>
Windows
</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="transport-protocol-local-remote">
</a>
Transport Support for Local and Remote Connections
</h4>
</div>
</div>
</div>
<p>
TCP/IP transport supports connections to local or remote MySQL
servers.
</p>
<p>
Socket-file, named-pipe, and shared-memory transports support
connections only to local MySQL servers. (Named-pipe transport
does allow for remote connections, but this capability is not
implemented in MySQL.)
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="transport-protocol-localhost">
</a>
Interpretation of localhost
</h4>
</div>
</div>
</div>
<p>
If the transport protocol is not specified explicitly,
<code class="literal">
localhost
</code>
is interpreted as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
On Unix and Unix-like systems, a connection to
<code class="literal">
localhost
</code>
results in a socket-file
connection.
</p>
</li>
<li class="listitem">
<p>
Otherwise, a connection to
<code class="literal">
localhost
</code>
results in a TCP/IP connection to
<code class="literal">
127.0.0.1
</code>
.
</p>
</li>
</ul>
</div>
<p>
If the transport protocol is specified explicitly,
<code class="literal">
localhost
</code>
is interpreted with respect to that
protocol. For example, with
<a class="link" href="connection-options.html#option_general_protocol">
<code class="option">
--protocol=TCP
</code>
</a>
, a connection to
<code class="literal">
localhost
</code>
results in a TCP/IP connection to
<code class="literal">
127.0.0.1
</code>
on all platforms.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="transport-protocol-encryption">
</a>
Encryption and Security Characteristics
</h4>
</div>
</div>
</div>
<p>
TCP/IP and socket-file transports are subject to TLS/SSL
encryption, using the options described in
<a class="xref" href="connection-options.html#encrypted-connection-options" title="Command Options for Encrypted Connections">
Command Options for Encrypted Connections
</a>
. Named-pipe and
shared-memory transports are not subject to TLS/SSL encryption.
</p>
<p>
A connection is secure by default if made over a transport
protocol that is secure by default. Otherwise, for protocols
that are subject to TLS/SSL encryption, a connection may be made
secure using encryption:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
TCP/IP connections are not secure by default, but can be
encrypted to make them secure.
</p>
</li>
<li class="listitem">
<p>
Socket-file connections are secure by default. They can also
be encrypted, but encrypting a socket-file connection makes
it no more secure and increases CPU load.
</p>
</li>
<li class="listitem">
<p>
Named-pipe connections are not secure by default, and are
not subject to encryption to make them secure. However, the
<a class="link" href="server-system-variables.html#sysvar_named_pipe_full_access_group">
<code class="literal">
named_pipe_full_access_group
</code>
</a>
system variable is available to control which MySQL users
are permitted to use named-pipe connections.
</p>
</li>
<li class="listitem">
<p>
Shared-memory connections are secure by default.
</p>
</li>
</ul>
</div>
<p>
If the
<a class="link" href="server-system-variables.html#sysvar_require_secure_transport">
<code class="literal">
require_secure_transport
</code>
</a>
system variable is enabled, the server permits only connections
that use some form of secure transport. Per the preceding
remarks, connections that use TCP/IP encrypted using TLS/SSL, a
socket file, or shared memory are secure connections. TCP/IP
connections not encrypted using TLS/SSL and named-pipe
connections are not secure.
</p>
<p>
See also
<a class="xref" href="using-encrypted-connections.html#mandatory-encrypted-connections" title="Configuring Encrypted Connections as Mandatory">
Configuring Encrypted Connections as Mandatory
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="transport-protocol-compression">
</a>
Connection Compression
</h4>
</div>
</div>
</div>
<p>
All transport protocols are subject to use of compression on the
traffic between the client and server. If both compression and
encryption are used for a given connection, compression occurs
before encryption. For more information, see
<a class="xref" href="connection-compression-control.html" title="6.2.8 Connection Compression Control">
Section 6.2.8, “Connection Compression Control”
</a>
.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndbxfrm.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-programs-ndbxfrm">
</a>
25.5.32 ndbxfrm — Compress, Decompress, Encrypt, and Decrypt
Files Created by NDB Cluster
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045095072560">
</a>
<p>
The
<a class="link" href="mysql-cluster-programs-ndbxfrm.html" title="25.5.32 ndbxfrm — Compress, Decompress, Encrypt, and Decrypt Files Created by NDB Cluster">
<span class="command">
<strong>
ndbxfrm
</strong>
</span>
</a>
utility can be used to
decompress, decrypt, and output information about files created
by NDB Cluster that are compressed, encrypted, or both. It can
also be used to compress or encrypt files.
</p>
<p>
</p>
<h4>
<a name="idm46045095069040">
</a>
Usage
</h4>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa39489309"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">ndbxfrm <span class="token property">--info</span> <em class="replaceable">file</em><span class="token punctuation">[</span> <em class="replaceable">file</em> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">]</span>
ndbxfrm <span class="token property">--compress</span> <em class="replaceable">input_file</em> <em class="replaceable">output_file</em>
ndbxfrm <span class="token constant">--decrypt-password</span><span class="token attr-value"><span class="token punctuation">=</span><em class="replaceable">password</em></span> <em class="replaceable">input_file</em> <em class="replaceable">output_file</em>
ndbxfrm <span class="token punctuation">[</span><span class="token constant">--encrypt-ldf-iter-count</span><span class="token attr-value"><span class="token punctuation">=</span>#<span class="token punctuation">]</span></span> <span class="token constant">--encrypt-password</span><span class="token attr-value"><span class="token punctuation">=</span><em class="replaceable">password</em></span> <em class="replaceable">input_file</em> <em class="replaceable">output_file</em></code></pre>
</div>
<p>
<em class="replaceable">
<code>
input_file
</code>
</em>
and
<em class="replaceable">
<code>
output_file
</code>
</em>
cannot be the same file.
</p>
<h4>
<a name="idm46045095061760">
</a>
Options
</h4>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="option_ndbxfrm_compress">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_compress">
<code class="option">
--compress
</code>
</a>
,
<code class="option">
-c
</code>
</p>
<a class="indexterm" name="idm46045095058352">
</a>
<a class="indexterm" name="idm46045095056864">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for compress">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--compress
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Compresses the input file, using the same compression method
as is used for compressing NDB Cluster backups, and writes
the output to an output file. To decompress a compressed
<code class="literal">
NDB
</code>
backup file that is not encrypted, it
is necessary only to invoke
<a class="link" href="mysql-cluster-programs-ndbxfrm.html" title="25.5.32 ndbxfrm — Compress, Decompress, Encrypt, and Decrypt Files Created by NDB Cluster">
<span class="command">
<strong>
ndbxfrm
</strong>
</span>
</a>
using
the names of the compressed file and an output file (with no
options required).
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_decrypt-key">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-key">
<code class="option">
--decrypt-key=
<em class="replaceable">
<code>
key
</code>
</em>
</code>
</a>
,
<code class="option">
-K
</code>
<em class="replaceable">
<code>
key
</code>
</em>
</p>
<a class="indexterm" name="idm46045095043776">
</a>
<a class="indexterm" name="idm46045095042288">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for decrypt-key">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--decrypt-key=key
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Decrypts a file encrypted by
<code class="literal">
NDB
</code>
using
the supplied key.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
This option cannot be used together with
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-password">
<code class="option">
--decrypt-password
</code>
</a>
.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_decrypt-key-from-stdin">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-key-from-stdin">
<code class="option">
--decrypt-key-from-stdin
</code>
</a>
</p>
<a class="indexterm" name="idm46045095029888">
</a>
<a class="indexterm" name="idm46045095028384">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for decrypt-key-from-stdin">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--decrypt-key-from-stdin
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Decrypts a file encrypted by
<code class="literal">
NDB
</code>
using
the key supplied from
<code class="literal">
stdin
</code>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_decrypt-password">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-password">
<code class="option">
--decrypt-password=
<em class="replaceable">
<code>
password
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045095016992">
</a>
<a class="indexterm" name="idm46045095015504">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for decrypt-password">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--decrypt-password=password
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Decrypts a file encrypted by
<code class="literal">
NDB
</code>
using
the password supplied.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
This option cannot be used together with
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-key">
<code class="option">
--decrypt-key
</code>
</a>
.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_decrypt-password-from-stdin">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-password-from-stdin">
<code class="option">
--decrypt-password-from-stdin[=TRUE|FALSE]
</code>
</a>
</p>
<a class="indexterm" name="idm46045094998560">
</a>
<a class="indexterm" name="idm46045094997056">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for decrypt-password-from-stdin">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--decrypt-password-from-stdin
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Decrypts a file encrypted by
<code class="literal">
NDB
</code>
, using a
password supplied from standard input. This is similar to
entering a password after invoking
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
<a class="link" href="mysql-command-options.html#option_mysql_password">
<code class="option">
--password
</code>
</a>
with no password
following the option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_defaults-extra-file">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_defaults-extra-file">
<code class="option">
--defaults-extra-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045094984240">
</a>
<a class="indexterm" name="idm46045094982784">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-extra-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-extra-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given file after global files are read.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_defaults-file">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_defaults-file">
<code class="option">
--defaults-file
</code>
</a>
</p>
<a class="indexterm" name="idm46045094968496">
</a>
<a class="indexterm" name="idm46045094967008">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-file">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-file=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read default options from given file only.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_defaults-group-suffix">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_defaults-group-suffix">
<code class="option">
--defaults-group-suffix
</code>
</a>
</p>
<a class="indexterm" name="idm46045094952736">
</a>
<a class="indexterm" name="idm46045094951280">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for defaults-group-suffix">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--defaults-group-suffix=string
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Also read groups with
<code class="literal">
CONCAT(
<em class="replaceable">
<code>
group
</code>
</em>
,
<em class="replaceable">
<code>
suffix
</code>
</em>
)
</code>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_detailed-info">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_detailed-info">
<code class="option">
--detailed-info
</code>
</a>
</p>
<a class="indexterm" name="idm46045094935360">
</a>
<a class="indexterm" name="idm46045094933872">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for detailed-info">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-block-size=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Boolean
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
FALSE
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Print out file information like
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_info">
<code class="option">
--info
</code>
</a>
, but include the
file's header and trailer.
</p>
<p>
Example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-simple"><div class="docs-select-all right" id="sa90998230"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple">$<span class="token operator">></span> ndbxfrm <span class="token operator">--</span>detailed<span class="token operator">-</span>info S0<span class="token punctuation">.</span>sysfile
File<span class="token operator">=</span><span class="token operator">/</span>var<span class="token operator">/</span>lib<span class="token operator">/</span>cluster<span class="token operator">-</span>data<span class="token operator">/</span>ndb_7_fs<span class="token operator">/</span>D1<span class="token operator">/</span>NDBCNTR<span class="token operator">/</span>S0<span class="token punctuation">.</span>sysfile<span class="token punctuation">,</span> compression<span class="token operator">=</span>no<span class="token punctuation">,</span> encryption<span class="token operator">=</span>yes
header<span class="token operator">:</span> <span class="token punctuation">{</span>
fixed_header<span class="token operator">:</span> <span class="token punctuation">{</span>
magic<span class="token operator">:</span> <span class="token punctuation">{</span>
magic<span class="token operator">:</span> <span class="token punctuation">{</span> 78<span class="token punctuation">,</span> 68<span class="token punctuation">,</span> 66<span class="token punctuation">,</span> 88<span class="token punctuation">,</span> 70<span class="token punctuation">,</span> 82<span class="token punctuation">,</span> 77<span class="token punctuation">,</span> 49 <span class="token punctuation">}</span><span class="token punctuation">,</span>
endian<span class="token operator">:</span> 18364758544493064720<span class="token punctuation">,</span>
header_size<span class="token operator">:</span> 32768<span class="token punctuation">,</span>
fixed_header_size<span class="token operator">:</span> 160<span class="token punctuation">,</span>
zeros<span class="token operator">:</span> <span class="token punctuation">{</span> 0<span class="token punctuation">,</span> 0 <span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token punctuation">,</span>
flags<span class="token operator">:</span> 73728<span class="token punctuation">,</span>
flag_extended<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_zeros<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_file_checksum<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_data_checksum<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_compress<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_compress_method<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_compress_padding<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_encrypt<span class="token operator">:</span> 18<span class="token punctuation">,</span>
flag_encrypt_cipher<span class="token operator">:</span> 2<span class="token punctuation">,</span>
flag_encrypt_krm<span class="token operator">:</span> 1<span class="token punctuation">,</span>
flag_encrypt_padding<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_encrypt_key_selection_mode<span class="token operator">:</span> 0<span class="token punctuation">,</span>
dbg_writer_ndb_version<span class="token operator">:</span> 524320<span class="token punctuation">,</span>
octets_size<span class="token operator">:</span> 32<span class="token punctuation">,</span>
file_block_size<span class="token operator">:</span> 32768<span class="token punctuation">,</span>
trailer_max_size<span class="token operator">:</span> 80<span class="token punctuation">,</span>
file_checksum<span class="token operator">:</span> <span class="token punctuation">{</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0 <span class="token punctuation">}</span><span class="token punctuation">,</span>
data_checksum<span class="token operator">:</span> <span class="token punctuation">{</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0 <span class="token punctuation">}</span><span class="token punctuation">,</span>
zeros01<span class="token operator">:</span> <span class="token punctuation">{</span> 0 <span class="token punctuation">}</span><span class="token punctuation">,</span>
compress_dbg_writer_header_version<span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
compress_dbg_writer_library_version<span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
encrypt_dbg_writer_header_version<span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
encrypt_dbg_writer_library_version<span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
encrypt_key_definition_iterator_count<span class="token operator">:</span> 100000<span class="token punctuation">,</span>
encrypt_krm_keying_material_size<span class="token operator">:</span> 32<span class="token punctuation">,</span>
encrypt_krm_keying_material_count<span class="token operator">:</span> 1<span class="token punctuation">,</span>
encrypt_key_data_unit_size<span class="token operator">:</span> 32768<span class="token punctuation">,</span>
encrypt_krm_keying_material_position_in_octets<span class="token operator">:</span> 0<span class="token punctuation">,</span>
<span class="token punctuation">}</span><span class="token punctuation">,</span>
octets<span class="token operator">:</span> <span class="token punctuation">{</span>
102<span class="token punctuation">,</span> 68<span class="token punctuation">,</span> 56<span class="token punctuation">,</span> 125<span class="token punctuation">,</span> 78<span class="token punctuation">,</span> 217<span class="token punctuation">,</span> 110<span class="token punctuation">,</span> 94<span class="token punctuation">,</span> 145<span class="token punctuation">,</span> 121<span class="token punctuation">,</span> 203<span class="token punctuation">,</span> 234<span class="token punctuation">,</span> 26<span class="token punctuation">,</span> 164<span class="token punctuation">,</span> 137<span class="token punctuation">,</span> 180<span class="token punctuation">,</span>
100<span class="token punctuation">,</span> 224<span class="token punctuation">,</span> 7<span class="token punctuation">,</span> 88<span class="token punctuation">,</span> 173<span class="token punctuation">,</span> 123<span class="token punctuation">,</span> 209<span class="token punctuation">,</span> 110<span class="token punctuation">,</span> 185<span class="token punctuation">,</span> 227<span class="token punctuation">,</span> 85<span class="token punctuation">,</span> 174<span class="token punctuation">,</span> 109<span class="token punctuation">,</span> 123<span class="token punctuation">,</span> 96<span class="token punctuation">,</span> 156<span class="token punctuation">,</span>
<span class="token punctuation">}</span>
<span class="token punctuation">}</span>
trailer<span class="token operator">:</span> <span class="token punctuation">{</span>
fixed_trailer<span class="token operator">:</span> <span class="token punctuation">{</span>
flags<span class="token operator">:</span> 48<span class="token punctuation">,</span>
flag_extended<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_zeros<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_file_checksum<span class="token operator">:</span> 0<span class="token punctuation">,</span>
flag_data_checksum<span class="token operator">:</span> 3<span class="token punctuation">,</span>
data_size<span class="token operator">:</span> 512<span class="token punctuation">,</span>
file_checksum<span class="token operator">:</span> <span class="token punctuation">{</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0<span class="token punctuation">,</span> 0 <span class="token punctuation">}</span><span class="token punctuation">,</span>
data_checksum<span class="token operator">:</span> <span class="token punctuation">{</span> 226<span class="token punctuation">,</span> 223<span class="token punctuation">,</span> 102<span class="token punctuation">,</span> 207 <span class="token punctuation">}</span><span class="token punctuation">,</span>
magic<span class="token operator">:</span> <span class="token punctuation">{</span>
zeros<span class="token operator">:</span> <span class="token punctuation">{</span> 0<span class="token punctuation">,</span> 0 <span class="token punctuation">}</span>
fixed_trailer_size<span class="token operator">:</span> 56<span class="token punctuation">,</span>
trailer_size<span class="token operator">:</span> 32256<span class="token punctuation">,</span>
endian<span class="token operator">:</span> 18364758544493064720<span class="token punctuation">,</span>
magic<span class="token operator">:</span> <span class="token punctuation">{</span> 78<span class="token punctuation">,</span> 68<span class="token punctuation">,</span> 66<span class="token punctuation">,</span> 88<span class="token punctuation">,</span> 70<span class="token punctuation">,</span> 82<span class="token punctuation">,</span> 77<span class="token punctuation">,</span> 49 <span class="token punctuation">}</span><span class="token punctuation">,</span>
<span class="token punctuation">}</span><span class="token punctuation">,</span>
<span class="token punctuation">}</span>
<span class="token punctuation">}</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-block-size">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-block-size">
<code class="option">
--encrypt-block-size=
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045094914560">
</a>
<a class="indexterm" name="idm46045094913104">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-block-size">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-block-size=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
2147483647
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Size of input data chunks that are encrypted as a unit. Used
with XTS; set to
<code class="literal">
0
</code>
(the default) for CBC
mode.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-cipher">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-cipher">
<code class="option">
--encrypt-cipher=
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045094892928">
</a>
<a class="indexterm" name="idm46045094891440">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-cipher">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-cipher=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
1
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
2147483647
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Cipher used for encryption. Set to
<code class="literal">
1
</code>
for
CBC mode (the default), or
<code class="literal">
2
</code>
for XTS.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-kdf-iter-count">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-kdf-iter-count">
<code class="option">
--encrypt-kdf-iter-count=
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
,
<code class="option">
-k
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</p>
<a class="indexterm" name="idm46045094870048">
</a>
<a class="indexterm" name="idm46045094868544">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-kdf-iter-count">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-kdf-iter-count=#
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
2147483647
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
When encrypting a file, specifies the number of iterations
to use for the encryption key. Requires the
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-password">
<code class="option">
--encrypt-password
</code>
</a>
option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-key">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-key">
<code class="option">
--encrypt-key=
<em class="replaceable">
<code>
key
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045094847920">
</a>
<a class="indexterm" name="idm46045094846432">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-key">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-key=key
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Encrypts a file using the supplied key.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
This option cannot be used together with
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-password">
<code class="option">
--encrypt-password
</code>
</a>
.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-key-from-stdin">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-key-from-stdin">
<code class="option">
--encrypt-key-from-stdin
</code>
</a>
</p>
<a class="indexterm" name="idm46045094834848">
</a>
<a class="indexterm" name="idm46045094833344">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-key-from-stdin">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-key-from-stdin
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Encrypt a file using the key supplied from
<code class="literal">
stdin
</code>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-password">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-password">
<code class="option">
--encrypt-password=
<em class="replaceable">
<code>
password
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045094822656">
</a>
<a class="indexterm" name="idm46045094821168">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-password">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-password=password
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Encrypts the backup file using the password supplied by the
option. The password must meet the requirements listed here:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Uses any of the printable ASCII characters except
<code class="literal">
!
</code>
,
<code class="literal">
'
</code>
,
<code class="literal">
"
</code>
,
<code class="literal">
$
</code>
,
<code class="literal">
%
</code>
,
<code class="literal">
\
</code>
,
<code class="literal">
`
</code>
, and
<code class="literal">
^
</code>
</p>
</li>
<li class="listitem">
<p>
Is no more than 256 characters in length
</p>
</li>
<li class="listitem">
<p>
Is enclosed by single or double quotation marks
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
This option cannot be used together with
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-key">
<code class="option">
--encrypt-key
</code>
</a>
.
</p>
</div>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_encrypt-password-from-stdin">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-password-from-stdin">
<code class="option">
--encrypt-password-from-stdin[=TRUE|FALSE]
</code>
</a>
</p>
<a class="indexterm" name="idm46045094796608">
</a>
<a class="indexterm" name="idm46045094795104">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for encrypt-password-from-stdin">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--encrypt-password-from-stdin
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Encrypts a file using a password supplied from standard
input. This is similar to entering a password is entered
after invoking
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
<a class="link" href="mysql-command-options.html#option_mysql_password">
<code class="option">
--password
</code>
</a>
with no password
following the option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_help">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_help">
<code class="option">
--help
</code>
</a>
,
<code class="option">
-?
</code>
</p>
<a class="indexterm" name="idm46045094782720">
</a>
<a class="indexterm" name="idm46045094781232">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for help">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--help
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Prints usage information for the program.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_info">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_info">
<code class="option">
--info
</code>
</a>
,
<code class="option">
-i
</code>
</p>
<a class="indexterm" name="idm46045094771328">
</a>
<a class="indexterm" name="idm46045094769840">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for info">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--info
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Prints the following information about one or more input
files:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
The name of the file
</p>
</li>
<li class="listitem">
<p>
Whether the file is compressed
(
<code class="literal">
compression=yes
</code>
or
<code class="literal">
compression=no
</code>
)
</p>
</li>
<li class="listitem">
<p>
Whether the file is encrypted
(
<code class="literal">
encryption=yes
</code>
or
<code class="literal">
encryption=no
</code>
)
</p>
</li>
</ul>
</div>
<p>
Example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa38042283"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">ndbxfrm</span> <span class="token property">-i</span> BACKUP-10-0<span class="token punctuation">.</span>5<span class="token punctuation">.</span>Data BACKUP-10<span class="token punctuation">.</span>5<span class="token punctuation">.</span>ctl BACKUP-10<span class="token punctuation">.</span>5<span class="token punctuation">.</span>log
File<span class="token attr-value"><span class="token punctuation">=</span>BACKUP-10-0.5.Data,</span> compression<span class="token attr-value"><span class="token punctuation">=</span>no,</span> encryption<span class="token attr-value"><span class="token punctuation">=</span>yes</span>
File<span class="token attr-value"><span class="token punctuation">=</span>BACKUP-10.5.ctl,</span> compression<span class="token attr-value"><span class="token punctuation">=</span>no,</span> encryption<span class="token attr-value"><span class="token punctuation">=</span>yes</span>
File<span class="token attr-value"><span class="token punctuation">=</span>BACKUP-10.5.log,</span> compression<span class="token attr-value"><span class="token punctuation">=</span>no,</span> encryption<span class="token attr-value"><span class="token punctuation">=</span>yes</span></code></pre>
</div>
<p>
You can also see the file's header and trailer using
the
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_detailed-info">
<code class="option">
--detailed-info
</code>
</a>
option.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_login-path">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_login-path">
<code class="option">
--login-path
</code>
</a>
</p>
<a class="indexterm" name="idm46045094750544">
</a>
<a class="indexterm" name="idm46045094749056">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for login-path">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--login-path=path
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
String
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
[none]
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Read given path from login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_no-login-paths">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_no-login-paths">
<code class="option">
--no-login-paths
</code>
</a>
</p>
<a class="indexterm" name="idm46045094734784">
</a>
<a class="indexterm" name="idm46045094733296">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-login-paths">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-login-paths
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Skips reading options from the login path file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_no-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_no-defaults">
<code class="option">
--no-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045094723584">
</a>
<a class="indexterm" name="idm46045094722096">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for no-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--no-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Do not read default options from any option file other than
login file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_print-defaults">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_print-defaults">
<code class="option">
--print-defaults
</code>
</a>
</p>
<a class="indexterm" name="idm46045094712272">
</a>
<a class="indexterm" name="idm46045094710784">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for print-defaults">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--print-defaults
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Print program argument list and exit.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_usage">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_usage">
<code class="option">
--usage
</code>
</a>
,
<code class="option">
-?
</code>
</p>
<a class="indexterm" name="idm46045094700800">
</a>
<a class="indexterm" name="idm46045094699312">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for usage">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--usage
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Synonym for
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_help">
<code class="option">
--help
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndbxfrm_version">
</a>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_version">
<code class="option">
--version
</code>
</a>
,
<code class="option">
-V
</code>
</p>
<a class="indexterm" name="idm46045094688336">
</a>
<a class="indexterm" name="idm46045094686848">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for version">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--version
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Prints out version information.
</p>
</li>
</ul>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndbxfrm.html" title="25.5.32 ndbxfrm — Compress, Decompress, Encrypt, and Decrypt Files Created by NDB Cluster">
<span class="command">
<strong>
ndbxfrm
</strong>
</span>
</a>
can encrypt backups created by any
version of NDB Cluster. The
<code class="filename">
.Data
</code>
,
<code class="filename">
.ctl
</code>
, and
<code class="filename">
.log
</code>
files
comprising the backup must be encrypted separately, and these
files must be encrypted separately for each data node. Once
encrypted, such backups can be decrypted only by
<a class="link" href="mysql-cluster-programs-ndbxfrm.html" title="25.5.32 ndbxfrm — Compress, Decompress, Encrypt, and Decrypt Files Created by NDB Cluster">
<span class="command">
<strong>
ndbxfrm
</strong>
</span>
</a>
,
<a class="link" href="mysql-cluster-programs-ndb-restore.html" title="25.5.23 ndb_restore — Restore an NDB Cluster Backup">
<span class="command">
<strong>
ndb_restore
</strong>
</span>
</a>
, or
<span class="command">
<strong>
ndb_print_backup
</strong>
</span>
.
</p>
<p>
An encrypted file can be re-encrypted with a new password using
the
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_encrypt-password">
<code class="option">
--encrypt-password
</code>
</a>
and
<a class="link" href="mysql-cluster-programs-ndbxfrm.html#option_ndbxfrm_decrypt-password">
<code class="option">
--decrypt-password
</code>
</a>
options
together, like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa43389308"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">ndbxfrm <span class="token constant">--decrypt-password</span><span class="token attr-value"><span class="token punctuation">=</span><em class="replaceable">old</em></span> <span class="token constant">--encrypt-password</span><span class="token attr-value"><span class="token punctuation">=</span><em class="replaceable">new</em></span> <em class="replaceable">input_file</em> <em class="replaceable">output_file</em></code></pre>
</div>
<p>
In the example just shown,
<em class="replaceable">
<code>
old
</code>
</em>
and
<em class="replaceable">
<code>
new
</code>
</em>
are the old and new passwords,
respectively; both of these must be quoted. The input file is
decrypted and then encrypted as the output file. The input file
itself is not changed; if you do not want it to be accessible
using the old password, you must remove the input file manually.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/subqueries.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="subqueries">
</a>
15.2.15 Subqueries
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="scalar-subqueries.html">
15.2.15.1 The Subquery as Scalar Operand
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="comparisons-using-subqueries.html">
15.2.15.2 Comparisons Using Subqueries
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="any-in-some-subqueries.html">
15.2.15.3 Subqueries with ANY, IN, or SOME
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="all-subqueries.html">
15.2.15.4 Subqueries with ALL
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="row-subqueries.html">
15.2.15.5 Row Subqueries
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="exists-and-not-exists-subqueries.html">
15.2.15.6 Subqueries with EXISTS or NOT EXISTS
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="correlated-subqueries.html">
15.2.15.7 Correlated Subqueries
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="derived-tables.html">
15.2.15.8 Derived Tables
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="lateral-derived-tables.html">
15.2.15.9 Lateral Derived Tables
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="subquery-errors.html">
15.2.15.10 Subquery Errors
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="optimizing-subqueries.html">
15.2.15.11 Optimizing Subqueries
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="subquery-restrictions.html">
15.2.15.12 Restrictions on Subqueries
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045180116960">
</a>
<a class="indexterm" name="idm46045180115888">
</a>
<a class="indexterm" name="idm46045180114816">
</a>
<a class="indexterm" name="idm46045180113328">
</a>
<p>
A subquery is a
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement
within another statement.
</p>
<p>
All subquery forms and operations that the SQL standard requires
are supported, as well as a few features that are MySQL-specific.
</p>
<p>
Here is an example of a subquery:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa95095469"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> column1 <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> column1 <span class="token keyword">FROM</span> t2<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
In this example,
<code class="literal">
SELECT * FROM t1 ...
</code>
is the
<span class="emphasis">
<em>
outer query
</em>
</span>
(or
<span class="emphasis">
<em>
outer
statement
</em>
</span>
), and
<code class="literal">
(SELECT column1 FROM
t2)
</code>
is the
<span class="emphasis">
<em>
subquery
</em>
</span>
. We say that
the subquery is
<span class="emphasis">
<em>
nested
</em>
</span>
within the outer
query, and in fact it is possible to nest subqueries within other
subqueries, to a considerable depth. A subquery must always appear
within parentheses.
</p>
<p>
The main advantages of subqueries are:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
They allow queries that are
<span class="emphasis">
<em>
structured
</em>
</span>
so
that it is possible to isolate each part of a statement.
</p>
</li>
<li class="listitem">
<p>
They provide alternative ways to perform operations that would
otherwise require complex joins and unions.
</p>
</li>
<li class="listitem">
<p>
Many people find subqueries more readable than complex joins
or unions. Indeed, it was the innovation of subqueries that
gave people the original idea of calling the early SQL
<span class="quote">
“
<span class="quote">
Structured Query Language.
</span>
”
</span>
</p>
</li>
</ul>
</div>
<p>
Here is an example statement that shows the major points about
subquery syntax as specified by the SQL standard and supported in
MySQL:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa48806874"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DELETE</span> <span class="token keyword">FROM</span> t1
<span class="token keyword">WHERE</span> s11 <span class="token operator">></span> <span class="token keyword">ANY</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token comment" spellcheck="true">/* no hint */</span> <span class="token keyword">FROM</span> t2
<span class="token keyword">WHERE</span> <span class="token operator">NOT</span> <span class="token keyword">EXISTS</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t3
<span class="token keyword">WHERE</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">5</span><span class="token operator">*</span>t2<span class="token punctuation">.</span>s1<span class="token punctuation">,</span><span class="token number">77</span><span class="token punctuation">)</span><span class="token operator">=</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> <span class="token number">50</span><span class="token punctuation">,</span><span class="token number">11</span><span class="token operator">*</span>s1 <span class="token keyword">FROM</span> t4 <span class="token keyword">UNION</span> <span class="token keyword">SELECT</span> <span class="token number">50</span><span class="token punctuation">,</span><span class="token number">77</span> <span class="token keyword">FROM</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t5<span class="token punctuation">)</span> <span class="token keyword">AS</span> t5<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
A subquery can return a scalar (a single value), a single row, a
single column, or a table (one or more rows of one or more
columns). These are called scalar, column, row, and table
subqueries. Subqueries that return a particular kind of result
often can be used only in certain contexts, as described in the
following sections.
</p>
<p>
There are few restrictions on the type of statements in which
subqueries can be used. A subquery can contain many of the
keywords or clauses that an ordinary
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
can contain:
<code class="literal">
DISTINCT
</code>
,
<code class="literal">
GROUP BY
</code>
,
<code class="literal">
ORDER BY
</code>
,
<code class="literal">
LIMIT
</code>
, joins,
index hints,
<a class="link" href="union.html" title="15.2.18 UNION Clause">
<code class="literal">
UNION
</code>
</a>
constructs,
comments, functions, and so on.
</p>
<p>
<a class="link" href="table.html" title="15.2.16 TABLE Statement">
<code class="literal">
TABLE
</code>
</a>
and
<a class="link" href="values.html" title="15.2.19 VALUES Statement">
<code class="literal">
VALUES
</code>
</a>
statements can be used in
subqueries. Subqueries using
<code class="literal">
VALUES
</code>
are
generally more verbose versions of subqueries that can be
rewritten more compactly using set notation, or with
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
or
<code class="literal">
TABLE
</code>
syntax; assuming that table
<code class="literal">
ts
</code>
is created using
the statement
<a class="link" href="create-table-select.html" title="15.1.20.4 CREATE TABLE ... SELECT Statement">
<code class="literal">
CREATE TABLE
ts VALUES ROW(2), ROW(4), ROW(6)
</code>
</a>
, the statements shown
here are all equivalent:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa78820006"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tt
<span class="token keyword">WHERE</span> b <span class="token operator">></span> <span class="token keyword">ANY</span> <span class="token punctuation">(</span><span class="token keyword">VALUES</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tt
<span class="token keyword">WHERE</span> b <span class="token operator">></span> <span class="token keyword">ANY</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> ts<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> tt
<span class="token keyword">WHERE</span> b <span class="token operator">></span> <span class="token keyword">ANY</span> <span class="token punctuation">(</span><span class="token keyword">TABLE</span> ts<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
Examples of
<a class="link" href="table.html" title="15.2.16 TABLE Statement">
<code class="literal">
TABLE
</code>
</a>
subqueries are
shown in the sections that follow.
</p>
<p>
A subquery's outer statement can be any one of:
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
,
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
,
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
,
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
</code>
</a>
, or
<a class="link" href="do.html" title="15.2.3 DO Statement">
<code class="literal">
DO
</code>
</a>
.
</p>
<p>
For information about how the optimizer handles subqueries, see
<a class="xref" href="subquery-optimization.html" title="10.2.2 Optimizing Subqueries, Derived Tables, View References, and Common Table Expressions">
Section 10.2.2, “Optimizing Subqueries, Derived Tables, View References, and Common Table
Expressions”
</a>
. For a discussion of
restrictions on subquery use, including performance issues for
certain forms of subquery syntax, see
<a class="xref" href="subquery-restrictions.html" title="15.2.15.12 Restrictions on Subqueries">
Section 15.2.15.12, “Restrictions on Subqueries”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/telemetry-system-variables.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="telemetry-system-variables">
</a>
35.2 Telemetry Variables
</h2>
</div>
</div>
</div>
<p>
The following table lists the Telemetry variables.
</p>
<div class="table">
<a name="idm46045060000784">
</a>
<p class="title">
<b>
Table 35.1 Telemetry Variable Summary
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Reference for telemetry system variables.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Name
</th>
<th scope="col">
Cmd-Line
</th>
<th scope="col">
Option File
</th>
<th scope="col">
System Var
</th>
<th scope="col">
Status Var
</th>
<th scope="col">
Var Scope
</th>
<th scope="col">
Dynamic
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<a class="link" href="server-status-variables.html#statvar_telemetry.live_sessions">
telemetry.live_sessions
</a>
</th>
<td>
</td>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.metrics_reader_frequency_1">
telemetry.metrics_reader_frequency_1
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.metrics_reader_frequency_2">
telemetry.metrics_reader_frequency_2
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.metrics_reader_frequency_3">
telemetry.metrics_reader_frequency_3
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_bsp_max_export_batch_size">
telemetry.otel_bsp_max_export_batch_size
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_bsp_max_queue_size">
telemetry.otel_bsp_max_queue_size
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_bsp_schedule_delay">
telemetry.otel_bsp_schedule_delay
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_certificates">
telemetry.otel_exporter_otlp_metrics_certificates
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_cipher">
telemetry.otel_exporter_otlp_metrics_cipher
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_cipher_suite">
telemetry.otel_exporter_otlp_metrics_cipher_suite
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_client_certificates">
telemetry.otel_exporter_otlp_metrics_client_certificates
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_client_key">
telemetry.otel_exporter_otlp_metrics_client_key
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_compression">
telemetry.otel_exporter_otlp_metrics_compression
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_endpoint">
telemetry.otel_exporter_otlp_metrics_endpoint
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_headers">
telemetry.otel_exporter_otlp_metrics_headers
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_min_tls">
telemetry.otel_exporter_otlp_metrics_max_tls
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_min_tls">
telemetry.otel_exporter_otlp_metrics_min_tls
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_protocol">
telemetry.otel_exporter_otlp_metrics_protocol
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-metrics-configuration.html#sysvar_telemetry.otel_exporter_otlp_metrics_timeout">
telemetry.otel_exporter_otlp_metrics_timeout
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_certificates">
telemetry.otel_exporter_otlp_traces_certificates
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_cipher">
telemetry.otel_exporter_otlp_traces_cipher
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_cipher_suite">
telemetry.otel_exporter_otlp_traces_cipher_suite
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_client_certificates">
telemetry.otel_exporter_otlp_traces_client_certificates
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_client_key">
telemetry.otel_exporter_otlp_traces_client_key
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_compression">
telemetry.otel_exporter_otlp_traces_compression
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_endpoint">
telemetry.otel_exporter_otlp_traces_endpoint
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_headers">
telemetry.otel_exporter_otlp_traces_headers
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_max_tls">
telemetry.otel_exporter_otlp_traces_max_tls
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_min_tls">
telemetry.otel_exporter_otlp_traces_min_tls
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_protocol">
telemetry.otel_exporter_otlp_traces_protocol
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_exporter_otlp_traces_timeout">
telemetry.otel_exporter_otlp_traces_timeout
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_log_level">
telemetry.otel_log_level
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.otel_resource_attributes">
telemetry.otel_resource_attributes
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.query_text_enabled">
telemetry.query_text_enabled
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="telemetry-trace-configuration.html#sysvar_telemetry.trace_enabled">
telemetry.trace_enabled
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th scope="col" style="width: 402.312px;">
Name
</th>
<th scope="col" style="width: 45.3281px;">
Cmd-Line
</th>
<th scope="col" style="width: 57.4375px;">
Option File
</th>
<th scope="col" style="width: 59.9219px;">
System Var
</th>
<th scope="col" style="width: 53.7188px;">
Status Var
</th>
<th scope="col" style="width: 49.9688px;">
Var Scope
</th>
<th scope="col" style="width: 69.3125px;">
Dynamic
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/windows-create-option-file.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="windows-create-option-file">
</a>
2.3.3.2 Creating an Option File
</h4>
</div>
</div>
</div>
<p>
If you need to specify startup options when you run the server,
you can indicate them on the command line or place them in an
option file. For options that are used every time the server
starts, you may find it most convenient to use an option file to
specify your MySQL configuration. This is particularly true
under the following circumstances:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The installation or data directory locations are different
from the default locations (
<code class="filename">
C:\Program
Files\MySQL\MySQL Server 8.4
</code>
and
<code class="filename">
C:\Program Files\MySQL\MySQL Server
8.4\data
</code>
).
</p>
</li>
<li class="listitem">
<p>
You need to tune the server settings, such as memory, cache,
or InnoDB configuration information.
</p>
</li>
</ul>
</div>
<p>
When the MySQL server starts on Windows, it looks for option
files in several locations, such as the Windows directory,
<code class="filename">
C:\
</code>
, and the MySQL installation directory
(for the full list of locations, see
<a class="xref" href="option-files.html" title="6.2.2.2 Using Option Files">
Section 6.2.2.2, “Using Option Files”
</a>
). The Windows directory typically
is named something like
<code class="filename">
C:\WINDOWS
</code>
. You can
determine its exact location from the value of the
<code class="literal">
WINDIR
</code>
environment variable using the
following command:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa94356362"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">C:\></span><span class="token command"> echo</span> %WINDIR%</code></pre>
</div>
<p>
MySQL looks for options in each location first in the
<code class="filename">
my.ini
</code>
file, and then in the
<code class="filename">
my.cnf
</code>
file. However, to avoid confusion,
it is best if you use only one file. If your PC uses a boot
loader where
<code class="filename">
C:
</code>
is not the boot drive, your
only option is to use the
<code class="filename">
my.ini
</code>
file.
Whichever option file you use, it must be a plain text file.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
When using MySQL Configurator to configure MySQL Server, it creates the
<code class="filename">
my.ini
</code>
at the default location, and the
user executing MySQL Configurator is granted full permissions to this
new
<code class="filename">
my.ini
</code>
file.
</p>
<p>
In other words, be sure that the MySQL Server user has
permission to read the
<code class="filename">
my.ini
</code>
file.
</p>
</div>
<p>
You can also make use of the example option files included with
your MySQL distribution; see
<a class="xref" href="server-configuration-defaults.html" title="7.1.2 Server Configuration Defaults">
Section 7.1.2, “Server Configuration Defaults”
</a>
.
</p>
<p>
An option file can be created and modified with any text editor,
such as Notepad. For example, if MySQL is installed in
<code class="filename">
E:\mysql
</code>
and the data directory is in
<code class="filename">
E:\mydata\data
</code>
, you can create an option
file containing a
<code class="literal">
[mysqld]
</code>
section to specify
values for the
<code class="option">
basedir
</code>
and
<code class="option">
datadir
</code>
options:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa11459252"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token comment" spellcheck="true"># set basedir to your installation path</span>
<span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>E:/mysql</span>
<span class="token comment" spellcheck="true"># set datadir to the location of your data directory</span>
<span class="token constant">datadir</span><span class="token attr-value"><span class="token punctuation">=</span>E:/mydata/data</span></code></pre>
</div>
<p>
Microsoft Windows path names are specified in option files using
(forward) slashes rather than backslashes. If you do use
backslashes, double them:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa80010762"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token comment" spellcheck="true"># set basedir to your installation path</span>
<span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>E:\\mysql</span>
<span class="token comment" spellcheck="true"># set datadir to the location of your data directory</span>
<span class="token constant">datadir</span><span class="token attr-value"><span class="token punctuation">=</span>E:\\mydata\\data</span></code></pre>
</div>
<p>
The rules for use of backslash in option file values are given
in
<a class="xref" href="option-files.html" title="6.2.2.2 Using Option Files">
Section 6.2.2.2, “Using Option Files”
</a>
.
</p>
<p>
The ZIP archive does not include a
<code class="filename">
data
</code>
directory. To initialize a MySQL installation by creating the
data directory and populating the tables in the mysql system
database, initialize MySQL using either
<a class="link" href="server-options.html#option_mysqld_initialize">
<code class="option">
--initialize
</code>
</a>
or
<a class="link" href="server-options.html#option_mysqld_initialize-insecure">
<code class="option">
--initialize-insecure
</code>
</a>
. For
additional information, see
<a class="xref" href="data-directory-initialization.html" title="2.9.1 Initializing the Data Directory">
Section 2.9.1, “Initializing the Data Directory”
</a>
.
</p>
<p>
If you would like to use a data directory in a different
location, you should copy the entire contents of the
<code class="filename">
data
</code>
directory to the new location. For
example, if you want to use
<code class="filename">
E:\mydata
</code>
as
the data directory instead, you must do two things:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Move the entire
<code class="filename">
data
</code>
directory and all
of its contents from the default location (for example
<code class="filename">
C:\Program Files\MySQL\MySQL Server
8.4\data
</code>
) to
<code class="filename">
E:\mydata
</code>
.
</p>
</li>
<li class="listitem">
<p>
Use a
<a class="link" href="server-system-variables.html#sysvar_datadir">
<code class="option">
--datadir
</code>
</a>
option to
specify the new data directory location each time you start
the server.
</p>
</li>
</ol>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/checking-gpg-signature-windows.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="checking-gpg-signature-windows">
</a>
2.1.4.3 Signature Checking Using Gpg4win for Windows
</h4>
</div>
</div>
</div>
<p>
The
<a class="xref" href="checking-gpg-signature.html" title="2.1.4.2 Signature Checking Using GnuPG">
Section 2.1.4.2, “Signature Checking Using GnuPG”
</a>
section describes
how to verify MySQL downloads using GPG. That guide also applies
to Microsoft Windows, but another option is to use a GUI tool
like
<a class="ulink" href="http://www.gpg4win.org/" target="_blank">
Gpg4win
</a>
. You
may use a different tool but our examples are based on Gpg4win,
and utilize its bundled
<code class="literal">
Kleopatra
</code>
GUI.
</p>
<p>
Download and install Gpg4win, load Kleopatra, and add the MySQL
Release Engineering certificate. Do this by clicking
<span class="guimenu">
File
</span>
,
<span class="guimenu">
Lookup on Server
</span>
.
Type "Mysql Release Engineering" into the search box and press
<span class="guibutton">
Search
</span>
.
</p>
<div class="figure">
<a name="gnupg-kleopatra-find-certificate">
</a>
<p class="title">
<b>
Figure 2.1 Kleopatra: Lookup on Server Wizard: Finding a Certificate
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt='Shows a search input field titled "Find" with "MySQL Release Engineering" entered. The one result contains the following values: Name=MySQL Release Engineering, [email protected], Valid From=2021-12-14, Valid Until="Unknown", and Key-ID=467B 942D 3A79 BD29. Available action buttons are: Search, Select All, Deselect All, Details, Import, and Close.' src="images/gnupg-kleopatra-find-certificate.png" style="width: 100%; max-width: 780px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
<p>
Select the "MySQL Release Engineering" certificate. The Key-ID
must reference "3A79 BD29", or choose
<span class="guibutton">
Details...
</span>
to confirm the certificate is
valid. Now, import it by clicking
<span class="guibutton">
Import
</span>
.
When the import dialog is displayed, choose
<span class="guibutton">
Okay
</span>
, and this certificate should now be
listed under the
<span class="guilabel">
Imported Certificates
</span>
tab.
</p>
<p>
Next, grant trust to the certificate. Select our certificate,
then from the main menu select
<span class="guimenu">
Certificates
</span>
,
<span class="guimenu">
Change Certification Power
</span>
, and click
<span class="guibutton">
Grant Power
</span>
.
</p>
<div class="figure">
<a name="gnupg-kleopatra-grant-certification-power">
</a>
<p class="title">
<b>
Figure 2.2 Kleopatra: Grant Certification Power for MySQL Release Engineering
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt='A "Grant Certification Power" dialogue is displayed. Available action buttons are: Grant Power and Cancel.' src="images/gnupg-kleopatra-grant-certification-power.png" style="width: 100%; max-width: 1022px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
<p>
Next, verify the downloaded MySQL package file. This requires
files for both the packaged file, and the signature. The
signature file must have the same name as the packaged file but
with an appended
<code class="filename">
.asc
</code>
extension, as shown
by the example in the following table. The signature is linked
to on the downloads page for each MySQL product. You must create
the
<code class="literal">
.asc
</code>
file with this signature.
</p>
<div class="table">
<a name="idm46045332819760">
</a>
<p class="title">
<b>
Table 2.2 MySQL Package and Signature Files for MySQL Server MSI for Microsoft
Windows
</b>
</p>
<div class="table-contents">
<table>
<colgroup>
<col style="width: 25%"/>
<col style="width: 75%"/>
</colgroup>
<thead>
<tr>
<th>
File Type
</th>
<th>
File Name
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
Distribution file
</td>
<td>
<code class="literal">
mysql-8.4.3-winx64.msi
</code>
</td>
</tr>
<tr>
<td>
Signature file
</td>
<td>
<code class="literal">
mysql-8.4.3-winx64.msi.asc
</code>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
Make sure that both files are stored in the same directory and
then run the following command to verify the signature for the
distribution file. Load the dialog from
<span class="guimenu">
File
</span>
,
<span class="guimenuitem">
Decrypt/Verify Files...
</span>
, and then
choose the
<code class="filename">
.asc
</code>
file.
</p>
<p>
The two most common results look like the following figures; and
although the "The data could not be verified." warning looks
problematic, the file check passed with success. For additional
information on what this warning means, click
<span class="guilabel">
Show
Audit Log
</span>
and compare it to
<a class="xref" href="checking-gpg-signature.html" title="2.1.4.2 Signature Checking Using GnuPG">
Section 2.1.4.2, “Signature Checking Using GnuPG”
</a>
. You may now execute
the MSI file.
</p>
<div class="figure">
<a name="gnupg-kleopatra-decrypt-okay-sig">
</a>
<p class="title">
<b>
Figure 2.3 Kleopatra: the Decrypt and Verify Results Dialog: Success
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt="It shows "The data could not be verified", and also shown is key information, such as the KeyID and email address, the key's sign on date, and also displays the name of the ASC file.." src="images/gnupg-kleopatra-decrypt-okay-sig.png" style="width: 100%; max-width: 628px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
<p>
Seeing an error such as
<span class="errortext">
Verification failed: No
Data.
</span>
means the file is invalid. Do not execute the
MSI file if you see this error.
</p>
<div class="figure">
<a name="gnupg-kleopatra-decrypt-invalid-sig">
</a>
<p class="title">
<b>
Figure 2.4 Kleopatra: the Decrypt and Verify Results Dialog: Bad
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt='It shows "Verification failed: No data." and also displays the name of the ASC file.' src="images/gnupg-kleopatra-decrypt-invalid-sig.png" style="width: 100%; max-width: 628px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-threads-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="performance-schema-threads-table">
</a>
29.12.22.8 The threads Table
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045067245728">
</a>
<a class="indexterm" name="idm46045067244240">
</a>
<a class="indexterm" name="idm46045067242752">
</a>
<p>
The
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table contains a row
for each server thread. Each row contains information about a
thread and indicates whether monitoring and historical event
logging are enabled for it:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa37471374"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>threads\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
THREAD_ID<span class="token punctuation">:</span> 1
NAME<span class="token punctuation">:</span> thread/sql/main
TYPE<span class="token punctuation">:</span> BACKGROUND
PROCESSLIST_ID<span class="token punctuation">:</span> NULL
PROCESSLIST_USER<span class="token punctuation">:</span> NULL
PROCESSLIST_HOST<span class="token punctuation">:</span> NULL
PROCESSLIST_DB<span class="token punctuation">:</span> mysql
PROCESSLIST_COMMAND<span class="token punctuation">:</span> NULL
PROCESSLIST_TIME<span class="token punctuation">:</span> 418094
PROCESSLIST_STATE<span class="token punctuation">:</span> NULL
PROCESSLIST_INFO<span class="token punctuation">:</span> NULL
PARENT_THREAD_ID<span class="token punctuation">:</span> NULL
ROLE<span class="token punctuation">:</span> NULL
INSTRUMENTED<span class="token punctuation">:</span> YES
HISTORY<span class="token punctuation">:</span> YES
CONNECTION_TYPE<span class="token punctuation">:</span> NULL
THREAD_OS_ID<span class="token punctuation">:</span> 5856
RESOURCE_GROUP<span class="token punctuation">:</span> SYS_default
EXECUTION_ENGINE<span class="token punctuation">:</span> PRIMARY
CONTROLLED_MEMORY<span class="token punctuation">:</span> 1456
MAX_CONTROLLED_MEMORY<span class="token punctuation">:</span> 67480
TOTAL_MEMORY<span class="token punctuation">:</span> 1270430
MAX_TOTAL_MEMORY<span class="token punctuation">:</span> 1307317
TELEMETRY_ACTIVE<span class="token punctuation">:</span> NO
...</span></code></pre>
</div>
<p>
When the Performance Schema initializes, it populates the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table based on the
threads in existence then. Thereafter, a new row is added each
time the server creates a thread.
</p>
<p>
The
<code class="literal">
INSTRUMENTED
</code>
and
<code class="literal">
HISTORY
</code>
column values for new threads are
determined by the contents of the
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table. For
information about how to use the
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table to control
these columns, see
<a class="xref" href="performance-schema-thread-filtering.html" title="29.4.6 Pre-Filtering by Thread">
Section 29.4.6, “Pre-Filtering by Thread”
</a>
.
</p>
<a class="indexterm" name="idm46045067229824">
</a>
<p>
Removal of rows from the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table occurs when threads end. For a thread associated with a
client session, removal occurs when the session ends. If a
client has auto-reconnect enabled and the session reconnects
after a disconnect, the session becomes associated with a new
row in the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table that has
a different
<code class="literal">
PROCESSLIST_ID
</code>
value. The
initial
<code class="literal">
INSTRUMENTED
</code>
and
<code class="literal">
HISTORY
</code>
values for the new thread may be
different from those of the original thread: The
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table may have
changed in the meantime, and if the
<code class="literal">
INSTRUMENTED
</code>
or
<code class="literal">
HISTORY
</code>
value for the original thread was changed after the row was
initialized, the change does not carry over to the new thread.
</p>
<p>
You can enable or disable thread monitoring (that is, whether
events executed by the thread are instrumented) and historical
event logging. To control the initial
<code class="literal">
INSTRUMENTED
</code>
and
<code class="literal">
HISTORY
</code>
values for new foreground threads, use the
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table. To control
these aspects of existing threads, set the
<code class="literal">
INSTRUMENTED
</code>
and
<code class="literal">
HISTORY
</code>
columns of
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table rows.
(For more information about the conditions under which thread
monitoring and historical event logging occur, see the
descriptions of the
<code class="literal">
INSTRUMENTED
</code>
and
<code class="literal">
HISTORY
</code>
columns.)
</p>
<p>
For a comparison of the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table columns with names having a prefix of
<code class="literal">
PROCESSLIST_
</code>
to other process information
sources, see
<a class="xref" href="processlist-access.html#processlist-sources" title="Sources of Process Information">
Sources of Process Information
</a>
.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
For thread information sources other than the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table, information
about threads for other users is shown only if the current
user has the
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege. That is not true of the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table; all rows are
shown to any user who has the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege for the
table. Users who should not be able to see threads for other
users by accessing the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table should not be given the
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege for it.
</p>
</div>
<p>
The
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table has these
columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
THREAD_ID
</code>
</p>
<p>
A unique thread identifier.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
NAME
</code>
</p>
<p>
The name associated with the thread instrumentation code
in the server. For example,
<code class="literal">
thread/sql/one_connection
</code>
corresponds
to the thread function in the code responsible for
handling a user connection, and
<code class="literal">
thread/sql/main
</code>
stands for the
<code class="literal">
main()
</code>
function of the server.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TYPE
</code>
</p>
<p>
The thread type, either
<code class="literal">
FOREGROUND
</code>
or
<code class="literal">
BACKGROUND
</code>
. User connection threads are
foreground threads. Threads associated with internal
server activity are background threads. Examples are
internal
<code class="literal">
InnoDB
</code>
threads,
<span class="quote">
“
<span class="quote">
binlog
dump
</span>
”
</span>
threads sending information to replicas, and
replication I/O and SQL threads.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_ID
</code>
</p>
<p>
For a foreground thread (associated with a user
connection), this is the connection identifier. This is
the same value displayed in the
<code class="literal">
ID
</code>
column of the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-processlist-table.html" title="28.3.23 The INFORMATION_SCHEMA PROCESSLIST Table">
<code class="literal">
PROCESSLIST
</code>
</a>
table, displayed
in the
<code class="literal">
Id
</code>
column of
<a class="link" href="show-processlist.html" title="15.7.7.31 SHOW PROCESSLIST Statement">
<code class="literal">
SHOW PROCESSLIST
</code>
</a>
output,
and returned by the
<a class="link" href="information-functions.html#function_connection-id">
<code class="literal">
CONNECTION_ID()
</code>
</a>
function
within the thread.
</p>
<p>
For a background thread (not associated with a user
connection),
<code class="literal">
PROCESSLIST_ID
</code>
is
<code class="literal">
NULL
</code>
, so the values are not unique.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_USER
</code>
</p>
<p>
The user associated with a foreground thread,
<code class="literal">
NULL
</code>
for a background thread.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_HOST
</code>
</p>
<p>
The host name of the client associated with a foreground
thread,
<code class="literal">
NULL
</code>
for a background thread.
</p>
<p>
Unlike the
<code class="literal">
HOST
</code>
column of the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-processlist-table.html" title="28.3.23 The INFORMATION_SCHEMA PROCESSLIST Table">
<code class="literal">
PROCESSLIST
</code>
</a>
table or the
<code class="literal">
Host
</code>
column of
<a class="link" href="show-processlist.html" title="15.7.7.31 SHOW PROCESSLIST Statement">
<code class="literal">
SHOW PROCESSLIST
</code>
</a>
output,
the
<code class="literal">
PROCESSLIST_HOST
</code>
column does not
include the port number for TCP/IP connections. To obtain
this information from the Performance Schema, enable the
socket instrumentation (which is not enabled by default)
and examine the
<a class="link" href="performance-schema-socket-instances-table.html" title="29.12.3.5 The socket_instances Table">
<code class="literal">
socket_instances
</code>
</a>
table:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42105410"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">NAME</span><span class="token punctuation">,</span> ENABLED<span class="token punctuation">,</span> TIMED
<span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>setup_instruments
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">LIKE</span> <span class="token string">'wait/io/socket%'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NAME <span class="token punctuation">|</span> ENABLED <span class="token punctuation">|</span> TIMED <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> wait/io/socket/sql/server_tcpip_socket <span class="token punctuation">|</span> NO <span class="token punctuation">|</span> NO <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> wait/io/socket/sql/server_unix_socket <span class="token punctuation">|</span> NO <span class="token punctuation">|</span> NO <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> wait/io/socket/sql/client_connection <span class="token punctuation">|</span> NO <span class="token punctuation">|</span> NO <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">3 rows in set (0.01 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">UPDATE</span> performance_schema<span class="token punctuation">.</span>setup_instruments
<span class="token keyword">SET</span> ENABLED<span class="token operator">=</span><span class="token string">'YES'</span>
<span class="token keyword">WHERE</span> <span class="token keyword">NAME</span> <span class="token operator">LIKE</span> <span class="token string">'wait/io/socket%'</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 3 rows affected (0.00 sec)</span>
<span class="token output">Rows matched: 3 Changed: 3 Warnings: 0</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> performance_schema<span class="token punctuation">.</span>socket_instances\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
EVENT_NAME<span class="token punctuation">:</span> wait/io/socket/sql/client_connection
OBJECT_INSTANCE_BEGIN<span class="token punctuation">:</span> 140612577298432
THREAD_ID<span class="token punctuation">:</span> 31
SOCKET_ID<span class="token punctuation">:</span> 53
IP<span class="token punctuation">:</span> <span class="token punctuation">:</span><span class="token punctuation">:</span>ffff<span class="token punctuation">:</span>127.0.0.1
PORT<span class="token punctuation">:</span> 55642
STATE<span class="token punctuation">:</span> ACTIVE
...</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_DB
</code>
</p>
<p>
The default database for the thread, or
<code class="literal">
NULL
</code>
if none has been selected.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_COMMAND
</code>
</p>
<p>
For foreground threads, the type of command the thread is
executing on behalf of the client, or
<code class="literal">
Sleep
</code>
if the session is idle. For
descriptions of thread commands, see
<a class="xref" href="thread-information.html" title="10.14 Examining Server Thread (Process) Information">
Section 10.14, “Examining Server Thread (Process) Information”
</a>
. The value of this
column corresponds to the
<code class="literal">
COM_
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
commands of the client/server protocol and
<code class="literal">
Com_
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
status variables. See
<a class="xref" href="server-status-variables.html" title="7.1.10 Server Status Variables">
Section 7.1.10, “Server Status Variables”
</a>
</p>
<p>
Background threads do not execute commands on behalf of
clients, so this column may be
<code class="literal">
NULL
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_TIME
</code>
</p>
<p>
The time in seconds that the thread has been in its
current state. For a replica SQL thread, the value is the
number of seconds between the timestamp of the last
replicated event and the real time of the replica host.
See
<a class="xref" href="replication-threads.html" title="19.2.3 Replication Threads">
Section 19.2.3, “Replication Threads”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_STATE
</code>
</p>
<p>
An action, event, or state that indicates what the thread
is doing. For descriptions of
<code class="literal">
PROCESSLIST_STATE
</code>
values, see
<a class="xref" href="thread-information.html" title="10.14 Examining Server Thread (Process) Information">
Section 10.14, “Examining Server Thread (Process) Information”
</a>
. If the value if
<code class="literal">
NULL
</code>
, the thread may correspond to an
idle client session or the work it is doing is not
instrumented with stages.
</p>
<p>
Most states correspond to very quick operations. If a
thread stays in a given state for many seconds, there
might be a problem that bears investigation.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PROCESSLIST_INFO
</code>
</p>
<p>
The statement the thread is executing, or
<code class="literal">
NULL
</code>
if it is executing no statement.
The statement might be the one sent to the server, or an
innermost statement if the statement executes other
statements. For example, if a
<code class="literal">
CALL
</code>
statement executes a stored procedure that is executing a
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement, the
<code class="literal">
PROCESSLIST_INFO
</code>
value shows the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PARENT_THREAD_ID
</code>
</p>
<p>
If this thread is a subthread (spawned by another thread),
this is the
<code class="literal">
THREAD_ID
</code>
value of the
spawning thread.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
ROLE
</code>
</p>
<p>
Unused.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
INSTRUMENTED
</code>
</p>
<p>
Whether events executed by the thread are instrumented.
The value is
<code class="literal">
YES
</code>
or
<code class="literal">
NO
</code>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
For foreground threads, the initial
<code class="literal">
INSTRUMENTED
</code>
value is determined by
whether the user account associated with the thread
matches any row in the
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table.
Matching is based on the values of the
<code class="literal">
PROCESSLIST_USER
</code>
and
<code class="literal">
PROCESSLIST_HOST
</code>
columns.
</p>
<p>
If the thread spawns a subthread, matching occurs
again for the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table row created for the subthread.
</p>
</li>
<li class="listitem">
<p>
For background threads,
<code class="literal">
INSTRUMENTED
</code>
is
<code class="literal">
YES
</code>
by default.
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
is not
consulted because there is no associated user for
background threads.
</p>
</li>
<li class="listitem">
<p>
For any thread, its
<code class="literal">
INSTRUMENTED
</code>
value can be changed during the lifetime of the
thread.
</p>
</li>
</ul>
</div>
<p>
For monitoring of events executed by the thread to occur,
these things must be true:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
The
<code class="literal">
thread_instrumentation
</code>
consumer
in the
<a class="link" href="performance-schema-setup-consumers-table.html" title="29.12.2.2 The setup_consumers Table">
<code class="literal">
setup_consumers
</code>
</a>
table must be
<code class="literal">
YES
</code>
.
</p>
</li>
<li class="listitem">
<p>
The
<code class="literal">
threads.INSTRUMENTED
</code>
column
must be
<code class="literal">
YES
</code>
.
</p>
</li>
<li class="listitem">
<p>
Monitoring occurs only for those thread events
produced from instruments that have the
<code class="literal">
ENABLED
</code>
column set to
<code class="literal">
YES
</code>
in the
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
table.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
HISTORY
</code>
</p>
<p>
Whether to log historical events for the thread. The value
is
<code class="literal">
YES
</code>
or
<code class="literal">
NO
</code>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
For foreground threads, the initial
<code class="literal">
HISTORY
</code>
value is determined by
whether the user account associated with the thread
matches any row in the
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
table.
Matching is based on the values of the
<code class="literal">
PROCESSLIST_USER
</code>
and
<code class="literal">
PROCESSLIST_HOST
</code>
columns.
</p>
<p>
If the thread spawns a subthread, matching occurs
again for the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table row created for the subthread.
</p>
</li>
<li class="listitem">
<p>
For background threads,
<code class="literal">
HISTORY
</code>
is
<code class="literal">
YES
</code>
by default.
<a class="link" href="performance-schema-setup-actors-table.html" title="29.12.2.1 The setup_actors Table">
<code class="literal">
setup_actors
</code>
</a>
is not
consulted because there is no associated user for
background threads.
</p>
</li>
<li class="listitem">
<p>
For any thread, its
<code class="literal">
HISTORY
</code>
value
can be changed during the lifetime of the thread.
</p>
</li>
</ul>
</div>
<p>
For historical event logging for the thread to occur,
these things must be true:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
The appropriate history-related consumers in the
<a class="link" href="performance-schema-setup-consumers-table.html" title="29.12.2.2 The setup_consumers Table">
<code class="literal">
setup_consumers
</code>
</a>
table
must be enabled. For example, wait event logging in
the
<a class="link" href="performance-schema-events-waits-history-table.html" title="29.12.4.2 The events_waits_history Table">
<code class="literal">
events_waits_history
</code>
</a>
and
<a class="link" href="performance-schema-events-waits-history-long-table.html" title="29.12.4.3 The events_waits_history_long Table">
<code class="literal">
events_waits_history_long
</code>
</a>
tables requires the corresponding
<code class="literal">
events_waits_history
</code>
and
<code class="literal">
events_waits_history_long
</code>
consumers
to be
<code class="literal">
YES
</code>
.
</p>
</li>
<li class="listitem">
<p>
The
<code class="literal">
threads.HISTORY
</code>
column must be
<code class="literal">
YES
</code>
.
</p>
</li>
<li class="listitem">
<p>
Logging occurs only for those thread events produced
from instruments that have the
<code class="literal">
ENABLED
</code>
column set to
<code class="literal">
YES
</code>
in the
<a class="link" href="performance-schema-setup-instruments-table.html" title="29.12.2.3 The setup_instruments Table">
<code class="literal">
setup_instruments
</code>
</a>
table.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
CONNECTION_TYPE
</code>
</p>
<p>
The protocol used to establish the connection, or
<code class="literal">
NULL
</code>
for background threads. Permitted
values are
<code class="literal">
TCP/IP
</code>
(TCP/IP connection
established without encryption),
<code class="literal">
SSL/TLS
</code>
(TCP/IP connection established
with encryption),
<code class="literal">
Socket
</code>
(Unix socket
file connection),
<code class="literal">
Named Pipe
</code>
(Windows
named pipe connection), and
<code class="literal">
Shared
Memory
</code>
(Windows shared memory connection).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
THREAD_OS_ID
</code>
</p>
<p>
The thread or task identifier as defined by the underlying
operating system, if there is one:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
When a MySQL thread is associated with the same
operating system thread for its lifetime,
<code class="literal">
THREAD_OS_ID
</code>
contains the operating
system thread ID.
</p>
</li>
<li class="listitem">
<p>
When a MySQL thread is not associated with the same
operating system thread for its lifetime,
<code class="literal">
THREAD_OS_ID
</code>
contains
<code class="literal">
NULL
</code>
. This is typical for user
sessions when the thread pool plugin is used (see
<a class="xref" href="thread-pool.html" title="7.6.3 MySQL Enterprise Thread Pool">
Section 7.6.3, “MySQL Enterprise Thread Pool”
</a>
).
</p>
</li>
</ul>
</div>
<p>
For Windows,
<code class="literal">
THREAD_OS_ID
</code>
corresponds
to the thread ID visible in Process Explorer
(
<a class="ulink" href="https://technet.microsoft.com/en-us/sysinternals/bb896653.aspx" target="_blank">
https://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
</a>
).
</p>
<p>
For Linux,
<code class="literal">
THREAD_OS_ID
</code>
corresponds to
the value of the
<code class="literal">
gettid()
</code>
function.
This value is exposed, for example, using the
<span class="command">
<strong>
perf
</strong>
</span>
or
<span class="command">
<strong>
ps -L
</strong>
</span>
commands, or in the
<code class="literal">
proc
</code>
file system
(
<code class="filename">
/proc/
<em class="replaceable">
<code>
[pid]
</code>
</em>
/task/
<em class="replaceable">
<code>
[tid]
</code>
</em>
</code>
).
For more information, see the
<code class="literal">
perf-stat(1)
</code>
,
<code class="literal">
ps(1)
</code>
,
and
<code class="literal">
proc(5)
</code>
man pages.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
RESOURCE_GROUP
</code>
</p>
<p>
The resource group label. This value is
<code class="literal">
NULL
</code>
if resource groups are not
supported on the current platform or server configuration
(see
<a class="xref" href="resource-groups.html#resource-group-restrictions" title="Resource Group Restrictions">
Resource Group Restrictions
</a>
).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
EXECUTION_ENGINE
</code>
</p>
<p>
The query execution engine. The value is either
<code class="literal">
PRIMARY
</code>
or
<code class="literal">
SECONDARY
</code>
. For use with HeatWave Service and
HeatWave, where the
<code class="literal">
PRIMARY
</code>
engine is
<code class="literal">
InnoDB
</code>
and the
<code class="literal">
SECONDARY
</code>
engine is HeatWave
(
<code class="literal">
RAPID
</code>
). For MySQL Community Edition Server, MySQL Enterprise Edition Server
(on-premise), and HeatWave Service without HeatWave, the value is
always
<code class="literal">
PRIMARY
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CONTROLLED_MEMORY
</code>
</p>
<p>
Amount of controlled memory used by the thread.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MAX_CONTROLLED_MEMORY
</code>
</p>
<p>
Maximum value of
<code class="literal">
CONTROLLED_MEMORY
</code>
seen
during the thread execution.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TOTAL_MEMORY
</code>
</p>
<p>
The current amount of memory, controlled or not, used by
the thread.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MAX_TOTAL_MEMORY
</code>
</p>
<p>
The maximum value of
<code class="literal">
TOTAL_MEMORY
</code>
seen
during the thread execution.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
TELEMETRY_ACTIVE
</code>
</p>
<p>
Whether the thread has an active telemetry seesion
attached. The value is
<code class="literal">
YES
</code>
or
<code class="literal">
NO
</code>
.
</p>
</li>
</ul>
</div>
<p>
The
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table has these
indexes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Primary key on (
<code class="literal">
THREAD_ID
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
NAME
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
PROCESSLIST_ID
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
PROCESSLIST_USER
</code>
,
<code class="literal">
PROCESSLIST_HOST
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
PROCESSLIST_HOST
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
THREAD_OS_ID
</code>
)
</p>
</li>
<li class="listitem">
<p>
Index on (
<code class="literal">
RESOURCE_GROUP
</code>
)
</p>
</li>
</ul>
</div>
<p>
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
is not permitted
for the
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-semisync-installation.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-semisync-installation">
</a>
19.4.10.1 Installing Semisynchronous Replication
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045136241856">
</a>
<a class="indexterm" name="idm46045136240352">
</a>
<p>
Semisynchronous replication is implemented using plugins, which
must be installed on the source and on the replicas to make
semisynchronous replication available on the instances. There
are different plugins for a source and for a replica. After a
plugin has been installed, you control it by means of the system
variables associated with it. These system variables are
available only when the associated plugin has been installed.
</p>
<p>
This section describes how to install the semisynchronous
replication plugins. For general information about installing
plugins, see
<a class="xref" href="plugin-loading.html" title="7.6.1 Installing and Uninstalling Plugins">
Section 7.6.1, “Installing and Uninstalling Plugins”
</a>
.
</p>
<p>
To use semisynchronous replication, the following requirements
must be satisfied:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The capability of installing plugins requires a MySQL server
that supports dynamic loading. To verify this, check that
the value of the
<a class="link" href="server-system-variables.html#sysvar_have_dynamic_loading">
<code class="literal">
have_dynamic_loading
</code>
</a>
system
variable is
<code class="literal">
YES
</code>
. Binary distributions
should support dynamic loading.
</p>
</li>
<li class="listitem">
<p>
Replication must already be working, see
<a class="xref" href="replication-configuration.html" title="19.1 Configuring Replication">
Section 19.1, “Configuring Replication”
</a>
.
</p>
</li>
<li class="listitem">
<p>
There must not be multiple replication channels configured.
Semisynchronous replication is only compatible with the
default replication channel. See
<a class="xref" href="replication-channels.html" title="19.2.2 Replication Channels">
Section 19.2.2, “Replication Channels”
</a>
.
</p>
</li>
</ul>
</div>
<p>
The file name suffix for the plugin library files differs per
platform (for example,
<code class="filename">
.so
</code>
for Unix and
Unix-like systems, and
<code class="filename">
.dll
</code>
for Windows).
The plugin and library file names are as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Source server:
<code class="literal">
rpl_semi_sync_source
</code>
plugin (
<code class="filename">
semisync_source.so
</code>
or
<code class="filename">
semisync_source.dll
</code>
library)
</p>
</li>
<li class="listitem">
<p>
Replica:
<code class="literal">
rpl_semi_sync_replica
</code>
plugin
(
<code class="filename">
semisync_replica.so
</code>
or
<code class="filename">
semisync_replica.dll
</code>
library)
</p>
</li>
</ul>
</div>
<p>
To be usable by a source or replica server, the appropriate
plugin library file must be located in the MySQL plugin
directory (the directory named by the
<a class="link" href="server-system-variables.html#sysvar_plugin_dir">
<code class="literal">
plugin_dir
</code>
</a>
system variable). If
necessary, configure the plugin directory location by setting
the value of
<a class="link" href="server-system-variables.html#sysvar_plugin_dir">
<code class="literal">
plugin_dir
</code>
</a>
at
server startup. The source plugin library file must be present
in the plugin directory of the source server. The replica plugin
library file must be present in the plugin directory of each
replica server.
</p>
<p>
To set up semisynchronous replication, use the following
instructions. The
<a class="link" href="install-plugin.html" title="15.7.4.4 INSTALL PLUGIN Statement">
<code class="literal">
INSTALL PLUGIN
</code>
</a>
,
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
GLOBAL
</code>
</a>
,
<a class="link" href="stop-replica.html" title="15.4.2.5 STOP REPLICA Statement">
<code class="literal">
STOP REPLICA
</code>
</a>
,
and
<a class="link" href="start-replica.html" title="15.4.2.4 START REPLICA Statement">
<code class="literal">
START REPLICA
</code>
</a>
statements
mentioned here require the
<a class="link" href="privileges-provided.html#priv_replication-slave-admin">
<code class="literal">
REPLICATION_SLAVE_ADMIN
</code>
</a>
privilege
(or the deprecated
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege).
</p>
<p>
To load the plugins, use the
<a class="link" href="install-plugin.html" title="15.7.4.4 INSTALL PLUGIN Statement">
<code class="literal">
INSTALL
PLUGIN
</code>
</a>
statement on the source and on each replica
that is to be semisynchronous, adjusting the
<code class="filename">
.so
</code>
suffix for your platform as necessary.
</p>
<p>
On the source:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa78929210"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSTALL</span> <span class="token keyword">PLUGIN</span> rpl_semi_sync_source <span class="token keyword">SONAME</span> <span class="token string">'semisync_source.so'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
On each replica:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa13748812"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSTALL</span> <span class="token keyword">PLUGIN</span> rpl_semi_sync_replica <span class="token keyword">SONAME</span> <span class="token string">'semisync_replica.so'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
If an attempt to install a plugin results in an error on Linux
similar to that shown here, you must install
<code class="literal">
libimf
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81280878"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSTALL</span> <span class="token keyword">PLUGIN</span> rpl_semi_sync_source <span class="token keyword">SONAME</span> <span class="token string">'semisync_source.so'</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1126 (HY000)<span class="token punctuation">:</span> Can't open shared library
'/usr/local/mysql/lib/plugin/semisync_source.so'
(errno<span class="token punctuation">:</span> 22 libimf.so<span class="token punctuation">:</span> cannot open shared object file<span class="token punctuation">:</span>
No such file or directory)</span></code></pre>
</div>
<p>
You can obtain
<code class="literal">
libimf
</code>
from
<a class="ulink" href="https://dev.mysql.com/downloads/os-linux.html" target="_top">
https://dev.mysql.com/downloads/os-linux.html
</a>
.
</p>
<p>
To verify plugin installation, examine the Information Schema
<a class="link" href="information-schema-plugins-table.html" title="28.3.22 The INFORMATION_SCHEMA PLUGINS Table">
<code class="literal">
PLUGINS
</code>
</a>
table or use the
<a class="link" href="show-plugins.html" title="15.7.7.27 SHOW PLUGINS Statement">
<code class="literal">
SHOW PLUGINS
</code>
</a>
statement (see
<a class="xref" href="obtaining-plugin-information.html" title="7.6.2 Obtaining Server Plugin Information">
Section 7.6.2, “Obtaining Server Plugin Information”
</a>
). For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa70914785"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> PLUGIN_NAME<span class="token punctuation">,</span> PLUGIN_STATUS
<span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span><span class="token keyword">PLUGINS</span>
<span class="token keyword">WHERE</span> PLUGIN_NAME <span class="token operator">LIKE</span> <span class="token string">'%semi%'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> PLUGIN_NAME <span class="token punctuation">|</span> PLUGIN_STATUS <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> rpl_semi_sync_source <span class="token punctuation">|</span> ACTIVE <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
If a plugin fails to initialize, check the server error log for
diagnostic messages.
</p>
<p>
After a semisynchronous replication plugin has been installed,
it is disabled by default. The plugins must be enabled both on
the source side and the replica side to enable semisynchronous
replication. If only one side is enabled, replication is
asynchronous. To enable the plugins, set the appropriate system
variable either at runtime using
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
GLOBAL
</code>
</a>
, or at server startup on the command line or in
an option file. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa50179445"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> rpl_semi_sync_source_enabled <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span></code></pre>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa88396607"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">GLOBAL</span> rpl_semi_sync_replica_enabled <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
If you enable semisynchronous replication on a replica at
runtime, you must also start the replication I/O (receiver)
thread (stopping it first if it is already running) to cause the
replica to connect to the source and register as a
semisynchronous replica:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81141087"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">STOP</span> <span class="token keyword">REPLICA</span> <span class="token keyword">IO_THREAD</span><span class="token punctuation">;</span>
<span class="token keyword">START</span> <span class="token keyword">REPLICA</span> <span class="token keyword">IO_THREAD</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
If the replication I/O (receiver) thread is already running and
you do not restart it, the replica continues to use asynchronous
replication.
</p>
<p>
A setting listed in an option file takes effect each time the
server starts. For example, you can set the variables in
<code class="filename">
my.cnf
</code>
files on the source and replica
servers as follows. On the source:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa6313411"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">rpl_semi_sync_source_enabled</span><span class="token attr-value"><span class="token punctuation">=</span>1</span></code></pre>
</div>
<p>
On each replica:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa87996701"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld]</span>
<span class="token constant">rpl_semi_sync_replica_enabled</span><span class="token attr-value"><span class="token punctuation">=</span>1</span></code></pre>
</div>
<p>
You can configure the behavior of the semisynchronous
replication plugins using the system variables that become
available when you install the plugins. For information on key
system variables, see
<a class="xref" href="replication-semisync-interface.html" title="19.4.10.2 Configuring Semisynchronous Replication">
Section 19.4.10.2, “Configuring Semisynchronous Replication”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-logging-management-commands.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysql-cluster-logging-management-commands">
</a>
25.6.3.1 NDB Cluster Logging Management Commands
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045093482240">
</a>
<a class="indexterm" name="idm46045093480752">
</a>
<a class="indexterm" name="idm46045093479664">
</a>
<a class="indexterm" name="idm46045093478592">
</a>
<a class="indexterm" name="idm46045093477104">
</a>
<a class="indexterm" name="idm46045093476016">
</a>
<p>
<a class="link" href="mysql-cluster-programs-ndb-mgm.html" title="25.5.5 ndb_mgm — The NDB Cluster Management Client">
<span class="command">
<strong>
ndb_mgm
</strong>
</span>
</a>
supports a number of management
commands related to the cluster log and node logs. In the
listing that follows,
<em class="replaceable">
<code>
node_id
</code>
</em>
denotes
either a storage node ID or the keyword
<code class="literal">
ALL
</code>
,
which indicates that the command should be applied to all of the
cluster's data nodes.
</p>
<a class="indexterm" name="idm46045093471440">
</a>
<a class="indexterm" name="idm46045093470400">
</a>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
CLUSTERLOG ON
</code>
</p>
<p>
Turns the cluster log on.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CLUSTERLOG OFF
</code>
</p>
<p>
Turns the cluster log off.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CLUSTERLOG INFO
</code>
</p>
<p>
Provides information about cluster log settings.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
<em class="replaceable">
<code>
node_id
</code>
</em>
CLUSTERLOG
<em class="replaceable">
<code>
category
</code>
</em>
=
<em class="replaceable">
<code>
threshold
</code>
</em>
</code>
</p>
<p>
Logs
<em class="replaceable">
<code>
category
</code>
</em>
events with
priority less than or equal to
<em class="replaceable">
<code>
threshold
</code>
</em>
in the cluster log.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
CLUSTERLOG FILTER
<em class="replaceable">
<code>
severity_level
</code>
</em>
</code>
</p>
<p>
Toggles cluster logging of events of the specified
<em class="replaceable">
<code>
severity_level
</code>
</em>
.
</p>
</li>
</ul>
</div>
<p>
The following table describes the default setting (for all data
nodes) of the cluster log category threshold. If an event has a
priority with a value lower than or equal to the priority
threshold, it is reported in the cluster log.
</p>
<a class="indexterm" name="idm46045093454656">
</a>
<a class="indexterm" name="idm46045093453152">
</a>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Events are reported per data node, and that the threshold can
be set to different values on different nodes.
</p>
</div>
<div class="table">
<a name="idm46045093451136">
</a>
<p class="title">
<b>
Table 25.26 Cluster log categories, with default threshold setting
</b>
</p>
<div class="table-contents">
<table>
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<thead>
<tr>
<th>
Category
</th>
<th>
Default threshold (All data nodes)
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="literal">
STARTUP
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
SHUTDOWN
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
STATISTICS
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
CHECKPOINT
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
NODERESTART
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
CONNECTION
</code>
</td>
<td>
<code class="literal">
8
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
ERROR
</code>
</td>
<td>
<code class="literal">
15
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
INFO
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
BACKUP
</code>
</td>
<td>
<code class="literal">
15
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
CONGESTION
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
<tr>
<td>
<code class="literal">
SCHEMA
</code>
</td>
<td>
<code class="literal">
7
</code>
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 354px;">
<thead>
<tr>
<th style="width: 105.812px;">
Category
</th>
<th style="width: 246.906px;">
Default threshold (All data nodes)
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
<p>
The
<code class="literal">
STATISTICS
</code>
category can provide a great
deal of useful data. See
<a class="xref" href="mysql-cluster-log-statistics.html" title="25.6.3.3 Using CLUSTERLOG STATISTICS in the NDB Cluster Management Client">
Section 25.6.3.3, “Using CLUSTERLOG STATISTICS in the NDB Cluster Management Client”
</a>
, for more
information.
</p>
<p>
Thresholds are used to filter events within each category. For
example, a
<code class="literal">
STARTUP
</code>
event with a priority of 3
is not logged unless the threshold for
<code class="literal">
STARTUP
</code>
is set to 3 or higher. Only events
with priority 3 or lower are sent if the threshold is 3.
</p>
<a class="indexterm" name="idm46045093409312">
</a>
<a class="indexterm" name="idm46045093407824">
</a>
<p>
The following table shows the event severity levels.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
These correspond to Unix
<code class="literal">
syslog
</code>
levels,
except for
<code class="literal">
LOG_EMERG
</code>
and
<code class="literal">
LOG_NOTICE
</code>
, which are not used or mapped.
</p>
</div>
<div class="table">
<a name="idm46045093403248">
</a>
<p class="title">
<b>
Table 25.27 Event severity levels
</b>
</p>
<div class="table-contents">
<table>
<colgroup>
<col style="width: 20%"/>
<col style="width: 20%"/>
<col style="width: 60%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Severity Level Value
</th>
<th scope="col">
Severity
</th>
<th scope="col">
Description
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
1
</th>
<td>
<code class="literal">
ALERT
</code>
</td>
<td>
A condition that should be corrected immediately, such as a corrupted
system database
</td>
</tr>
<tr>
<th scope="row">
2
</th>
<td>
<code class="literal">
CRITICAL
</code>
</td>
<td>
Critical conditions, such as device errors or insufficient resources
</td>
</tr>
<tr>
<th scope="row">
3
</th>
<td>
<code class="literal">
ERROR
</code>
</td>
<td>
Conditions that should be corrected, such as configuration errors
</td>
</tr>
<tr>
<th scope="row">
4
</th>
<td>
<code class="literal">
WARNING
</code>
</td>
<td>
Conditions that are not errors, but that might require special handling
</td>
</tr>
<tr>
<th scope="row">
5
</th>
<td>
<code class="literal">
INFO
</code>
</td>
<td>
Informational messages
</td>
</tr>
<tr>
<th scope="row">
6
</th>
<td>
<code class="literal">
DEBUG
</code>
</td>
<td>
Debugging messages used for
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDBCLUSTER
</code>
</a>
development
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
Event severity levels can be turned on or off (using
<code class="literal">
CLUSTERLOG FILTER
</code>
—see above). If a
severity level is turned on, then all events with a priority
less than or equal to the category thresholds are logged. If the
severity level is turned off then no events belonging to that
severity level are logged.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
Cluster log levels are set on a per
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
, per subscriber basis. This means
that, in an NDB Cluster with multiple management servers,
using a
<code class="literal">
CLUSTERLOG
</code>
command in an instance
of
<a class="link" href="mysql-cluster-programs-ndb-mgm.html" title="25.5.5 ndb_mgm — The NDB Cluster Management Client">
<span class="command">
<strong>
ndb_mgm
</strong>
</span>
</a>
connected to one management
server affects only logs generated by that management server
but not by any of the others. This also means that, should one
of the management servers be restarted, only logs generated by
that management server are affected by the resetting of log
levels caused by the restart.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/data-type-defaults.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="data-type-defaults">
</a>
13.6 Data Type Default Values
</h2>
</div>
</div>
</div>
<a class="indexterm" name="idm46045210878688">
</a>
<a class="indexterm" name="idm46045210877648">
</a>
<a class="indexterm" name="idm46045210876160">
</a>
<a class="indexterm" name="idm46045210875088">
</a>
<a class="indexterm" name="idm46045210873600">
</a>
<a class="indexterm" name="idm46045210872528">
</a>
<p>
Data type specifications can have explicit or implicit default
values.
</p>
<p>
A
<code class="literal">
DEFAULT
<em class="replaceable">
<code>
value
</code>
</em>
</code>
clause in a data type specification explicitly indicates a default
value for a column. Examples:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa73887269"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>
i <span class="token datatype">INT</span> <span class="token keyword">DEFAULT</span> <span class="token operator">-</span><span class="token number">1</span><span class="token punctuation">,</span>
c <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span> <span class="token keyword">DEFAULT</span> <span class="token string">''</span><span class="token punctuation">,</span>
price <span class="token datatype">DOUBLE</span><span class="token punctuation">(</span><span class="token number">16</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">)</span> <span class="token keyword">DEFAULT</span> <span class="token number">0.00</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<a class="indexterm" name="idm46045210868416">
</a>
<p>
<code class="literal">
SERIAL DEFAULT VALUE
</code>
is a special case. In the
definition of an integer column, it is an alias for
<code class="literal">
NOT
NULL AUTO_INCREMENT UNIQUE
</code>
.
</p>
<p>
Some aspects of explicit
<code class="literal">
DEFAULT
</code>
clause
handling are version dependent, as described following.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="data-type-defaults.html#data-type-defaults-explicit" title="Explicit Default Handling">
Explicit Default Handling
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="data-type-defaults.html#data-type-defaults-implicit" title="Implicit Default Handling">
Implicit Default Handling
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h3 class="title">
<a name="data-type-defaults-explicit">
</a>
Explicit Default Handling
</h3>
</div>
</div>
</div>
<p>
The default value specified in a
<code class="literal">
DEFAULT
</code>
clause can be a literal constant or an expression. With one
exception, enclose expression default values within parentheses
to distinguish them from literal constant default values.
Examples:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa46658563"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>
<span class="token comment" spellcheck="true">-- literal defaults</span>
i <span class="token datatype">INT</span> <span class="token keyword">DEFAULT</span> <span class="token number">0</span><span class="token punctuation">,</span>
c <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span> <span class="token keyword">DEFAULT</span> <span class="token string">''</span><span class="token punctuation">,</span>
<span class="token comment" spellcheck="true">-- expression defaults</span>
f <span class="token datatype">FLOAT</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token function">RAND</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">*</span> <span class="token function">RAND</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
b <span class="token datatype">BINARY</span><span class="token punctuation">(</span><span class="token number">16</span><span class="token punctuation">)</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token function">UUID_TO_BIN</span><span class="token punctuation">(</span><span class="token function">UUID</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
d <span class="token datatype">DATE</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token keyword">CURRENT_DATE</span> <span class="token operator">+</span> <span class="token keyword">INTERVAL</span> <span class="token number">1</span> <span class="token datatype">YEAR</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
p <span class="token keyword">POINT</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token function">Point</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
j <span class="token datatype">JSON</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token function">JSON_ARRAY</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The exception is that, for
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
and
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
DATETIME
</code>
</a>
columns, you can specify
the
<a class="link" href="date-and-time-functions.html#function_current-timestamp">
<code class="literal">
CURRENT_TIMESTAMP
</code>
</a>
function as
the default, without enclosing parentheses. See
<a class="xref" href="timestamp-initialization.html" title="13.2.5 Automatic Initialization and Updating for TIMESTAMP and DATETIME">
Section 13.2.5, “Automatic Initialization and Updating for TIMESTAMP and DATETIME”
</a>
.
</p>
<p>
The
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
BLOB
</code>
</a>
,
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
TEXT
</code>
</a>
,
<code class="literal">
GEOMETRY
</code>
, and
<a class="link" href="json.html" title="13.5 The JSON Data Type">
<code class="literal">
JSON
</code>
</a>
data types can be assigned a
default value only if the value is written as an expression,
even if the expression value is a literal:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
This is permitted (literal default specified as expression):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa46843920"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t2 <span class="token punctuation">(</span>b <span class="token datatype">BLOB</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token string">'abc'</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
This produces an error (literal default not specified as
expression):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa67057415"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t2 <span class="token punctuation">(</span>b <span class="token datatype">BLOB</span> <span class="token keyword">DEFAULT</span> <span class="token string">'abc'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
Expression default values must adhere to the following rules. An
error occurs if an expression contains disallowed constructs.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Literals, built-in functions (both deterministic and
nondeterministic), and operators are permitted.
</p>
</li>
<li class="listitem">
<p>
Subqueries, parameters, variables, stored functions, and
loadable functions are not permitted.
</p>
</li>
<li class="listitem">
<p>
An expression default value cannot depend on a column that
has the
<code class="literal">
AUTO_INCREMENT
</code>
attribute.
</p>
</li>
<li class="listitem">
<p>
An expression default value for one column can refer to
other table columns, with the exception that references to
generated columns or columns with expression default values
must be to columns that occur earlier in the table
definition. That is, expression default values cannot
contain forward references to generated columns or columns
with expression default values.
</p>
<p>
The ordering constraint also applies to the use of
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
to reorder table
columns. If the resulting table would have an expression
default value that contains a forward reference to a
generated column or column with an expression default value,
the statement fails.
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
If any component of an expression default value depends on the
SQL mode, different results may occur for different uses of
the table unless the SQL mode is the same during all uses.
</p>
</div>
<p>
For
<a class="link" href="create-table-like.html" title="15.1.20.3 CREATE TABLE ... LIKE Statement">
<code class="literal">
CREATE
TABLE ... LIKE
</code>
</a>
and
<a class="link" href="create-table-select.html" title="15.1.20.4 CREATE TABLE ... SELECT Statement">
<code class="literal">
CREATE
TABLE ... SELECT
</code>
</a>
, the destination table preserves
expression default values from the original table.
</p>
<p>
If an expression default value refers to a nondeterministic
function, any statement that causes the expression to be
evaluated is unsafe for statement-based replication. This
includes statements such as
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
and
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
. In this situation, if
binary logging is disabled, the statement is executed as normal.
If binary logging is enabled and
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
is set to
<code class="literal">
STATEMENT
</code>
, the statement is logged and
executed but a warning message is written to the error log,
because replicas might diverge. When
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
<code class="literal">
binlog_format
</code>
</a>
is set to
<code class="literal">
MIXED
</code>
or
<code class="literal">
ROW
</code>
, the
statement is executed as normal.
</p>
<p>
When inserting a new row, the default value for a column with an
expression default can be inserted either by omitting the column
name or by specifying the column as
<code class="literal">
DEFAULT
</code>
(just as for columns with literal defaults):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa51605933"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t4 <span class="token punctuation">(</span>uid <span class="token datatype">BINARY</span><span class="token punctuation">(</span><span class="token number">16</span><span class="token punctuation">)</span> <span class="token function">DEFAULT</span> <span class="token punctuation">(</span><span class="token function">UUID_TO_BIN</span><span class="token punctuation">(</span><span class="token function">UUID</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t4 <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t4 <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token keyword">DEFAULT</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">BIN_TO_UUID</span><span class="token punctuation">(</span>uid<span class="token punctuation">)</span> <span class="token keyword">AS</span> uid <span class="token keyword">FROM</span> t4<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> uid <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> f1109174<span class="token punctuation">-</span>94c9<span class="token punctuation">-</span>11e8<span class="token punctuation">-</span>971d<span class="token punctuation">-</span>3bf1095aa633 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> f110cf9a<span class="token punctuation">-</span>94c9<span class="token punctuation">-</span>11e8<span class="token punctuation">-</span>971d<span class="token punctuation">-</span>3bf1095aa633 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
However, the use of
<a class="link" href="miscellaneous-functions.html#function_default">
<code class="literal">
DEFAULT(
<em class="replaceable">
<code>
col_name
</code>
</em>
)
</code>
</a>
to specify the default value for a named column is permitted
only for columns that have a literal default value, not for
columns that have an expression default value.
</p>
<p>
Not all storage engines permit expression default values. For
those that do not, an
<a class="ulink" href="/doc/mysql-errors/8.4/en/server-error-reference.html#error_er_unsupported_action_on_default_val_generated" target="_top">
<code class="literal">
ER_UNSUPPORTED_ACTION_ON_DEFAULT_VAL_GENERATED
</code>
</a>
error occurs.
</p>
<p>
If a default value evaluates to a data type that differs from
the declared column type, implicit coercion to the declared type
occurs according to the usual MySQL type-conversion rules. See
<a class="xref" href="type-conversion.html" title="14.3 Type Conversion in Expression Evaluation">
Section 14.3, “Type Conversion in Expression Evaluation”
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h3 class="title">
<a name="data-type-defaults-implicit">
</a>
Implicit Default Handling
</h3>
</div>
</div>
</div>
<p>
If a data type specification includes no explicit
<code class="literal">
DEFAULT
</code>
value, MySQL determines the default
value as follows:
</p>
<p>
If the column can take
<code class="literal">
NULL
</code>
as a value, the
column is defined with an explicit
<code class="literal">
DEFAULT
NULL
</code>
clause.
</p>
<p>
If the column cannot take
<code class="literal">
NULL
</code>
as a value,
MySQL defines the column with no explicit
<code class="literal">
DEFAULT
</code>
clause.
</p>
<p>
For data entry into a
<code class="literal">
NOT NULL
</code>
column that
has no explicit
<code class="literal">
DEFAULT
</code>
clause, if an
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
or
<a class="link" href="replace.html" title="15.2.12 REPLACE Statement">
<code class="literal">
REPLACE
</code>
</a>
statement includes no
value for the column, or an
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
statement sets the column
to
<code class="literal">
NULL
</code>
, MySQL handles the column according
to the SQL mode in effect at the time:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If strict SQL mode is enabled, an error occurs for
transactional tables and the statement is rolled back. For
nontransactional tables, an error occurs, but if this
happens for the second or subsequent row of a multiple-row
statement, the preceding rows are inserted.
</p>
</li>
<li class="listitem">
<p>
If strict mode is not enabled, MySQL sets the column to the
implicit default value for the column data type.
</p>
</li>
</ul>
</div>
<p>
Suppose that a table
<code class="literal">
t
</code>
is defined as follows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa27376419"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t <span class="token punctuation">(</span>i <span class="token datatype">INT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
In this case,
<code class="literal">
i
</code>
has no explicit default, so
in strict mode each of the following statements produce an error
and no row is inserted. When not using strict mode, only the
third statement produces an error; the implicit default is
inserted for the first two statements, but the third fails
because
<a class="link" href="miscellaneous-functions.html#function_default">
<code class="literal">
DEFAULT(i)
</code>
</a>
cannot produce
a value:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa267408"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token keyword">DEFAULT</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token function">DEFAULT</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
See
<a class="xref" href="sql-mode.html" title="7.1.11 Server SQL Modes">
Section 7.1.11, “Server SQL Modes”
</a>
.
</p>
<p>
For a given table, the
<a class="link" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
<code class="literal">
SHOW CREATE
TABLE
</code>
</a>
statement displays which columns have an
explicit
<code class="literal">
DEFAULT
</code>
clause.
</p>
<p>
Implicit defaults are defined as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For numeric types, the default is
<code class="literal">
0
</code>
, with
the exception that for integer or floating-point types
declared with the
<code class="literal">
AUTO_INCREMENT
</code>
attribute, the default is the next value in the sequence.
</p>
</li>
<li class="listitem">
<p>
For date and time types other than
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
, the default is the
appropriate
<span class="quote">
“
<span class="quote">
zero
</span>
”
</span>
value for the type. This is
also true for
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
if
the
<a class="link" href="server-system-variables.html#sysvar_explicit_defaults_for_timestamp">
<code class="literal">
explicit_defaults_for_timestamp
</code>
</a>
system variable is enabled (see
<a class="xref" href="server-system-variables.html" title="7.1.8 Server System Variables">
Section 7.1.8, “Server System Variables”
</a>
). Otherwise, for
the first
<a class="link" href="datetime.html" title="13.2.2 The DATE, DATETIME, and TIMESTAMP Types">
<code class="literal">
TIMESTAMP
</code>
</a>
column in
a table, the default value is the current date and time. See
<a class="xref" href="date-and-time-types.html" title="13.2 Date and Time Data Types">
Section 13.2, “Date and Time Data Types”
</a>
.
</p>
</li>
<li class="listitem">
<p>
For string types other than
<a class="link" href="enum.html" title="13.3.5 The ENUM Type">
<code class="literal">
ENUM
</code>
</a>
, the default value is
the empty string. For
<a class="link" href="enum.html" title="13.3.5 The ENUM Type">
<code class="literal">
ENUM
</code>
</a>
,
the default is the first enumeration value.
</p>
</li>
</ul>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/partial-revokes.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="partial-revokes">
</a>
8.2.12 Privilege Restriction Using Partial Revokes
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045249008160">
</a>
<a class="indexterm" name="idm46045249007120">
</a>
<p>
It is possible to grant privileges that apply globally if the
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
system variable
is enabled. Specifically, for users who have privileges at the
global level,
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
enables privileges for specific schemas to be revoked while
leaving the privileges in place for other schemas. Privilege
restrictions thus imposed may be useful for administration of
accounts that have global privileges but should not be permitted
to access certain schemas. For example, it is possible to permit
an account to modify any table except those in the
<code class="literal">
mysql
</code>
system schema.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="partial-revokes.html#partial-revokes-usage" title="Using Partial Revokes">
Using Partial Revokes
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="partial-revokes.html#partial-revokes-versus-schema-grants" title="Partial Revokes Versus Explicit Schema Grants">
Partial Revokes Versus Explicit Schema Grants
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="partial-revokes.html#partial-revokes-disabling" title="Disabling Partial Revokes">
Disabling Partial Revokes
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="partial-revokes.html#partial-revokes-replication" title="Partial Revokes and Replication">
Partial Revokes and Replication
</a>
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
For brevity,
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE USER
</code>
</a>
statements shown here do not include passwords. For production
use, always assign account passwords.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="partial-revokes-usage">
</a>
Using Partial Revokes
</h4>
</div>
</div>
</div>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
system
variable controls whether privilege restrictions can be placed
on accounts. By default,
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
is disabled and
attempts to partially revoke global privileges produce an error:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa53350260"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token output">ERROR 1141 (42000)<span class="token punctuation">:</span> There is no such grant defined for user 'u1' on host '%'</span></code></pre>
</div>
<p>
To permit the
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
operation,
enable
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa57987228"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">PERSIST</span> partial_revokes <span class="token operator">=</span> <span class="token keyword">ON</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
sets a value for the running MySQL instance.
It also saves the value, causing it to carry over to subsequent
server restarts. To change the value for the running MySQL
instance without having it carry over to subsequent restarts,
use the
<code class="literal">
GLOBAL
</code>
keyword rather than
<code class="literal">
PERSIST
</code>
. See
<a class="xref" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
Section 15.7.6.1, “SET Syntax for Variable Assignment”
</a>
.
</p>
<p>
With
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
enabled,
the partial revoke succeeds:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa8106161"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE INSERT ON `world`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
lists partial revokes
as
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements in its
output. The result indicates that
<code class="literal">
u1
</code>
has
global
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
privileges, except that
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
cannot be exercised for
tables in the
<code class="literal">
world
</code>
schema. That is, access
by
<code class="literal">
u1
</code>
to
<code class="literal">
world
</code>
tables is
read only.
</p>
<p>
The server records privilege restrictions implemented through
partial revokes in the
<code class="literal">
mysql.user
</code>
system
table. If an account has partial revokes, its
<code class="literal">
User_attributes
</code>
column value has a
<code class="literal">
Restrictions
</code>
attribute:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42302203"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">User</span><span class="token punctuation">,</span> <span class="token keyword">Host</span><span class="token punctuation">,</span> User_attributes<span class="token operator">-</span><span class="token operator">>></span><span class="token string">'$.Restrictions'</span>
<span class="token keyword">FROM</span> mysql<span class="token punctuation">.</span><span class="token keyword">user</span> <span class="token keyword">WHERE</span> User_attributes<span class="token operator">-</span><span class="token operator">>></span><span class="token string">'$.Restrictions'</span> <span class="token operator"><></span> <span class="token string">''</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> User <span class="token punctuation">|</span> Host <span class="token punctuation">|</span> User_attributes<span class="token punctuation">-</span>>>'$.Restrictions' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> u1 <span class="token punctuation">|</span> % <span class="token punctuation">|</span> [{"Database": "world", "Privileges": ["INSERT"]}] <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Although partial revokes can be imposed for any schema,
privilege restrictions on the
<code class="literal">
mysql
</code>
system
schema in particular are useful as part of a strategy for
preventing regular accounts from modifying system accounts.
See
<a class="xref" href="account-categories.html#protecting-system-accounts" title="Protecting System Accounts Against Manipulation by Regular Accounts">
Protecting System Accounts Against Manipulation by Regular Accounts
</a>
.
</p>
</div>
<p>
Partial revoke operations are subject to these conditions:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
It is possible to use partial revokes to place restrictions
on nonexistent schemas, but only if the revoked privilege is
granted globally. If a privilege is not granted globally,
revoking it for a nonexistent schema produces an error.
</p>
</li>
<li class="listitem">
<p>
Partial revokes apply at the schema level only. You cannot
use partial revokes for privileges that apply only globally
(such as
<a class="link" href="privileges-provided.html#priv_file">
<code class="literal">
FILE
</code>
</a>
or
<a class="link" href="privileges-provided.html#priv_binlog-admin">
<code class="literal">
BINLOG_ADMIN
</code>
</a>
), or for table,
column, or routine privileges.
</p>
</li>
<li class="listitem">
<p>
In privilege assignments, enabling
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
causes
MySQL to interpret occurrences of unescaped
<code class="literal">
_
</code>
and
<code class="literal">
%
</code>
SQL wildcard
characters in schema names as literal characters, just as if
they had been escaped as
<code class="literal">
\_
</code>
and
<code class="literal">
\%
</code>
. Because this changes how MySQL
interprets privileges, it may be advisable to avoid
unescaped wildcard characters in privilege assignments for
installations where
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
may be
enabled.
</p>
</li>
</ul>
</div>
<p>
As mentioned previously, partial revokes of schema-level
privileges appear in
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
output as
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements. This
differs from how
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
represents
<span class="quote">
“
<span class="quote">
plain
</span>
”
</span>
schema-level privileges:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
When granted, schema-level privileges are represented by
their own
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statements in
the output:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa14536135"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT USAGE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT UPDATE ON `mysql`.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT DELETE ON `world`.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<p>
When revoked, schema-level privileges simply disappear from
the output. They do not appear as
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa67572"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT USAGE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
</ul>
</div>
<p>
When a user grants a privilege, any restriction the grantor has
on the privilege is inherited by the grantee, unless the grantee
already has the privilege without the restriction. Consider the
following two users, one of whom has the global
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa32096821"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">,</span> u2<span class="token punctuation">;</span>
<span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u2<span class="token punctuation">;</span></code></pre>
</div>
<p>
Suppose that an administrative user
<code class="literal">
admin
</code>
has
a global but partially revoked
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa56013833"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token keyword">admin</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> <span class="token keyword">admin</span> <span class="token keyword">WITH</span> <span class="token keyword">GRANT</span> <span class="token keyword">OPTION</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> <span class="token keyword">admin</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> <span class="token keyword">admin</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for admin@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT ON *.* TO `admin`@`%` WITH GRANT OPTION <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE SELECT ON `mysql`.* FROM `admin`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
If
<code class="literal">
admin
</code>
grants
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
globally to
<code class="literal">
u1
</code>
and
<code class="literal">
u2
</code>
, the result
differs for each user:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If
<code class="literal">
admin
</code>
grants
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
globally to
<code class="literal">
u1
</code>
, who has no
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege to begin
with,
<code class="literal">
u1
</code>
inherits the
<code class="literal">
admin
</code>
privilege restriction:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96113732"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE SELECT ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<p>
On the other hand,
<code class="literal">
u2
</code>
already holds a
global
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
privilege
without restriction.
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
can only add to a grantee's existing privileges, not reduce
them, so if
<code class="literal">
admin
</code>
grants
<a class="link" href="privileges-provided.html#priv_select">
<code class="literal">
SELECT
</code>
</a>
globally to
<code class="literal">
u2
</code>
,
<code class="literal">
u2
</code>
does not
inherit the
<code class="literal">
admin
</code>
restriction:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa36296370"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u2<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u2<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u2@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT ON *.* TO `u2`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
</ul>
</div>
<p>
If a
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement includes an
<code class="literal">
AS
<em class="replaceable">
<code>
user
</code>
</em>
</code>
clause,
the privilege restrictions applied are those on the user/role
combination specified by the clause, rather than those on the
user who executes the statement. For information about the
<code class="literal">
AS
</code>
clause, see
<a class="xref" href="grant.html" title="15.7.1.6 GRANT Statement">
Section 15.7.1.6, “GRANT Statement”
</a>
.
</p>
<p>
Restrictions on new privileges granted to an account are added
to any existing restrictions for that account:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa46117209"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE INSERT ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">DELETE</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> db2<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE UPDATE, DELETE ON `db2`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE INSERT ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Aggregation of privilege restrictions applies both when
privileges are partially revoked explicitly (as just shown) and
when restrictions are inherited implicitly from the user who
executes the statement or the user mentioned in an
<code class="literal">
AS
<em class="replaceable">
<code>
user
</code>
</em>
</code>
clause.
</p>
<p>
If an account has a privilege restriction on a schema:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The account cannot grant to other accounts a privilege on
the restricted schema or any object within it.
</p>
</li>
<li class="listitem">
<p>
Another account that does not have the restriction can grant
privileges to the restricted account for the restricted
schema or objects within it. Suppose that an unrestricted
user executes these statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa77274668"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token keyword">REVOKE</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token keyword">user</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span> <span class="token comment" spellcheck="true">-- grant table privilege</span>
<span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">(</span><span class="token keyword">Host</span><span class="token punctuation">,</span><span class="token keyword">User</span><span class="token punctuation">)</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span>db <span class="token keyword">TO</span> u1<span class="token punctuation">;</span> <span class="token comment" spellcheck="true">-- grant column privileges</span></code></pre>
</div>
<p>
The resulting account has these privileges, with the ability
to perform limited operations within the restricted schema:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa19162220"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE SELECT, INSERT, UPDATE ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT (`Host`, `User`) ON `mysql`.`db` TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT ON `mysql`.`user` TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
</ul>
</div>
<p>
If an account has a restriction on a global privilege, the
restriction is removed by any of these actions:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Granting the privilege globally to the account by an account
that has no restriction on the privilege.
</p>
</li>
<li class="listitem">
<p>
Granting the privilege at the schema level.
</p>
</li>
<li class="listitem">
<p>
Revoking the privilege globally.
</p>
</li>
</ul>
</div>
<p>
Consider a user
<code class="literal">
u1
</code>
who holds several
privileges globally, but with restrictions on
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
and
<a class="link" href="privileges-provided.html#priv_delete">
<code class="literal">
DELETE
</code>
</a>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa9492623"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">UPDATE</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE INSERT, UPDATE, DELETE ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Granting a privilege globally to
<code class="literal">
u1
</code>
from an
account with no restriction removes the privilege restriction.
For example, to remove the
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
restriction:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa77910924"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE UPDATE, DELETE ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Granting a privilege at the schema level to
<code class="literal">
u1
</code>
removes the privilege restriction. For
example, to remove the
<a class="link" href="privileges-provided.html#priv_update">
<code class="literal">
UPDATE
</code>
</a>
restriction:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa17000115"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">UPDATE</span> <span class="token keyword">ON</span> mysql<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE DELETE ON `mysql`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Revoking a global privilege removes the privilege, including any
restrictions on it. For example, to remove the
<a class="link" href="privileges-provided.html#priv_delete">
<code class="literal">
DELETE
</code>
</a>
restriction (at the cost
of removing all
<a class="link" href="privileges-provided.html#priv_delete">
<code class="literal">
DELETE
</code>
</a>
access):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa70077031"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT, UPDATE ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
If an account has a privilege at both the global and schema
levels, you must revoke it at the schema level twice to effect a
partial revoke. Suppose that
<code class="literal">
u1
</code>
has these
privileges, where
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
is held
both globally and on the
<code class="literal">
world
</code>
schema:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96392864"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">SELECT</span><span class="token punctuation">,</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT INSERT ON `world`.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Revoking
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
on
<code class="literal">
world
</code>
revokes the schema-level privilege
(
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
no longer displays
the schema-level
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa22854847"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Revoking
<a class="link" href="privileges-provided.html#priv_insert">
<code class="literal">
INSERT
</code>
</a>
on
<code class="literal">
world
</code>
again performs a partial revoke of the
global privilege (
<a class="link" href="show-grants.html" title="15.7.7.22 SHOW GRANTS Statement">
<code class="literal">
SHOW GRANTS
</code>
</a>
now
includes a schema-level
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statement):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa52614168"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">GRANTS</span> <span class="token keyword">FOR</span> u1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Grants for u1@% <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> GRANT SELECT, INSERT ON *.* TO `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> REVOKE INSERT ON `world`.* FROM `u1`@`%` <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="partial-revokes-versus-schema-grants">
</a>
Partial Revokes Versus Explicit Schema Grants
</h4>
</div>
</div>
</div>
<p>
To provide access to accounts for some schemas but not others,
partial revokes provide an alternative to the approach of
explicitly granting schema-level access without granting global
privileges. The two approaches have different advantages and
disadvantages.
</p>
<p>
Granting schema-level privileges and not global privileges:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Adding a new schema: The schema is inaccessible to existing
accounts by default. For any account to which the schema
should be accessible, the DBA must grant schema-level
access.
</p>
</li>
<li class="listitem">
<p>
Adding a new account: The DBA must grant schema-level access
for each schema to which the account should have access.
</p>
</li>
</ul>
</div>
<p>
Granting global privileges in conjunction with partial revokes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Adding a new schema: The schema is accessible to existing
accounts that have global privileges. For any such account
to which the schema should be inaccessible, the DBA must add
a partial revoke.
</p>
</li>
<li class="listitem">
<p>
Adding a new account: The DBA must grant the global
privileges, plus a partial revoke on each restricted schema.
</p>
</li>
</ul>
</div>
<p>
The approach that uses explicit schema-level grant is more
convenient for accounts for which access is limited to a few
schemas. The approach that uses partial revokes is more
convenient for accounts with broad access to all schemas except
a few.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="partial-revokes-disabling">
</a>
Disabling Partial Revokes
</h4>
</div>
</div>
</div>
<p>
Once enabled,
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
cannot be disabled if any account has privilege restrictions. If
any such account exists, disabling
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
fails:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For attempts to disable
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
at startup,
the server logs an error message and enables
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
For attempts to disable
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
at runtime,
an error occurs and the
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
value
remains unchanged.
</p>
</li>
</ul>
</div>
<p>
To disable
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
when
restrictions exist, the restrictions first must be removed:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Determine which accounts have partial revokes:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa11366089"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token keyword">User</span><span class="token punctuation">,</span> <span class="token keyword">Host</span><span class="token punctuation">,</span> User_attributes<span class="token operator">-</span><span class="token operator">>></span><span class="token string">'$.Restrictions'</span>
<span class="token keyword">FROM</span> mysql<span class="token punctuation">.</span><span class="token keyword">user</span> <span class="token keyword">WHERE</span> User_attributes<span class="token operator">-</span><span class="token operator">>></span><span class="token string">'$.Restrictions'</span> <span class="token operator"><></span> <span class="token string">''</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
For each such account, remove its privilege restrictions.
Suppose that the previous step shows account
<code class="literal">
u1
</code>
to have these restrictions:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa26695836"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token inlinejson"><span class="token punctuation">[</span><span class="token punctuation">{</span><span class="token property">"Database"</span><span class="token operator">:</span> <span class="token string">"world"</span><span class="token punctuation">,</span> <span class="token property">"Privileges"</span><span class="token operator">:</span> <span class="token punctuation">[</span><span class="token string">"INSERT"</span><span class="token punctuation">,</span> <span class="token string">"DELETE"</span><span class="token punctuation">]</span></span></code></pre>
</div>
<p>
Restriction removal can be done various ways:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Grant the privileges globally, without restrictions:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa81750350"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">GRANT</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Grant the privileges at the schema level:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa2362914"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">GRANT</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> world<span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> u1<span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Revoke the privileges globally (assuming that they are
no longer needed):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa3793715"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">REVOKE</span> <span class="token keyword">INSERT</span><span class="token punctuation">,</span> <span class="token keyword">DELETE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">FROM</span> u1<span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
Remove the account itself (assuming that it is no longer
needed):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa39713090"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">DROP</span> <span class="token keyword">USER</span> u1<span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
</li>
</ol>
</div>
<p>
After all privilege restrictions are removed, it is possible to
disable partial revokes:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa90645368"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">PERSIST</span> partial_revokes <span class="token operator">=</span> <span class="token keyword">OFF</span><span class="token punctuation">;</span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="partial-revokes-replication">
</a>
Partial Revokes and Replication
</h4>
</div>
</div>
</div>
<p>
In replication scenarios, if
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
is enabled on
any host, it must be enabled on all hosts. Otherwise,
<a class="link" href="revoke.html" title="15.7.1.8 REVOKE Statement">
<code class="literal">
REVOKE
</code>
</a>
statements to partially
revoke a global privilege do not have the same effect for all
hosts on which replication occurs, potentially resulting in
replication inconsistencies or errors.
</p>
<p>
When
<a class="link" href="server-system-variables.html#sysvar_partial_revokes">
<code class="literal">
partial_revokes
</code>
</a>
is
enabled, an extended syntax is recorded in the binary log for
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statements, including the
current user that issued the statement and their currently
active roles. If a user or a role recorded in this way does not
exist on the replica, the replication applier thread stops at
the
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement
with an error. Ensure that all user accounts that issue or might
issue
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statements on the
replication source server also exist on the replica, and have
the same set of roles as they have on the source.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-nodes-groups.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-nodes-groups">
</a>
25.2.2 NDB Cluster Nodes, Node Groups, Fragment Replicas, and Partitions
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045124217536">
</a>
<a class="indexterm" name="idm46045124216048">
</a>
<a class="indexterm" name="idm46045124214560">
</a>
<a class="indexterm" name="idm46045124213072">
</a>
<a class="indexterm" name="idm46045124212032">
</a>
<a class="indexterm" name="idm46045124210944">
</a>
<p>
This section discusses the manner in which NDB Cluster divides and
duplicates data for storage.
</p>
<p>
A number of concepts central to an understanding of this topic are
discussed in the next few paragraphs.
</p>
<p>
<b>
Data node.
</b>
An
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
or
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
process,
which stores one or more
<span class="firstterm">
fragment
replicas
</span>
—that is, copies of the
<span class="firstterm">
partitions
</span>
(discussed
later in this section) assigned to the node group of which the
node is a member.
</p>
<p>
Each data node should be located on a separate computer. While it
is also possible to host multiple data node processes on a single
computer, such a configuration is not usually recommended.
</p>
<p>
It is common for the terms
<span class="quote">
“
<span class="quote">
node
</span>
”
</span>
and
<span class="quote">
“
<span class="quote">
data
node
</span>
”
</span>
to be used interchangeably when referring to an
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
or
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
process;
where mentioned, management nodes (
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
processes) and SQL nodes (
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
processes) are
specified as such in this discussion.
</p>
<p>
<a name="mysql-cluster-nodes-groups-nodegroup">
</a>
<b>
Node group.
</b>
A node group consists of one or more nodes, and stores
partitions, or sets of
<span class="firstterm">
fragment
replicas
</span>
(see next item).
</p>
<p>
The number of node groups in an NDB Cluster is not directly
configurable; it is a function of the number of data nodes and of
the number of fragment replicas
(
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
configuration parameter), as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa60983693"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple"><span class="token punctuation">[</span><span class="token comment" spellcheck="true"># of node groups] = [# of data nodes] / NoOfReplicas</span></code></pre>
</div>
<p>
Thus, an NDB Cluster with 4 data nodes has 4 node groups if
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
is set to 1
in the
<code class="filename">
config.ini
</code>
file, 2 node groups if
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
is set to 2,
and 1 node group if
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
is set to 4.
Fragment replicas are discussed later in this section; for more
information about
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
, see
<a class="xref" href="mysql-cluster-ndbd-definition.html" title="25.4.3.6 Defining NDB Cluster Data Nodes">
Section 25.4.3.6, “Defining NDB Cluster Data Nodes”
</a>
.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
All node groups in an NDB Cluster must have the same number of
data nodes.
</p>
</div>
<p>
You can add new node groups (and thus new data nodes) online, to a
running NDB Cluster; see
<a class="xref" href="mysql-cluster-online-add-node.html" title="25.6.7 Adding NDB Cluster Data Nodes Online">
Section 25.6.7, “Adding NDB Cluster Data Nodes Online”
</a>
, for more
information.
</p>
<p>
<a name="mysql-cluster-nodes-groups-partition">
</a>
<b>
Partition.
</b>
This is a portion of the data stored by the cluster. Each node
is responsible for keeping at least one copy of any partitions
assigned to it (that is, at least one fragment replica)
available to the cluster.
</p>
<p>
The number of partitions used by default by NDB Cluster depends on
the number of data nodes and the number of LDM threads in use by
the data nodes, as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-simple"><div class="docs-select-all right" id="sa57526686"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-simple"><span class="token punctuation">[</span><span class="token comment" spellcheck="true"># of partitions] = [# of data nodes] * [# of LDM threads]</span></code></pre>
</div>
<p>
When using data nodes running
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
, the
number of LDM threads is controlled by the setting for
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbmtd-maxnoofexecutionthreads">
<code class="literal">
MaxNoOfExecutionThreads
</code>
</a>
.
When using
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
there is a single LDM thread,
which means that there are as many cluster partitions as nodes
participating in the cluster. This is also the case when using
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
with
<code class="literal">
MaxNoOfExecutionThreads
</code>
set to 3 or less. (You
should be aware that the number of LDM threads increases with the
value of this parameter, but not in a strictly linear fashion, and
that there are additional constraints on setting it; see the
description of
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbmtd-maxnoofexecutionthreads">
<code class="literal">
MaxNoOfExecutionThreads
</code>
</a>
for more information.)
</p>
<p>
<a name="mysql-cluster-nodes-groups-user-partitioning">
</a>
<b>
NDB and user-defined partitioning.
</b>
NDB Cluster normally partitions
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDBCLUSTER
</code>
</a>
tables automatically.
However, it is also possible to employ user-defined partitioning
with
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDBCLUSTER
</code>
</a>
tables. This is
subject to the following limitations:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Only the
<code class="literal">
KEY
</code>
and
<code class="literal">
LINEAR
KEY
</code>
partitioning schemes are supported in production
with
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
tables.
</p>
</li>
<li class="listitem">
<p>
The maximum number of partitions that may be defined
explicitly for any
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
table is
<code class="literal">
8 * [
<em class="replaceable">
<code>
number of LDM
threads
</code>
</em>
] * [
<em class="replaceable">
<code>
number of node
groups
</code>
</em>
]
</code>
, the number of node groups in
an NDB Cluster being determined as discussed previously in
this section. When running
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
for data
node processes, setting the number of LDM threads has no
effect (since
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbmtd-threadconfig">
<code class="literal">
ThreadConfig
</code>
</a>
applies
only to
<a class="link" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
<span class="command">
<strong>
ndbmtd
</strong>
</span>
</a>
); in such cases, this value
can be treated as though it were equal to 1 for purposes of
performing this calculation.
</p>
<p>
See
<a class="xref" href="mysql-cluster-programs-ndbmtd.html" title="25.5.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)">
Section 25.5.3, “ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)”
</a>
, for more
information.
</p>
</li>
</ol>
</div>
<p>
For more information relating to NDB Cluster and user-defined
partitioning, see
<a class="xref" href="mysql-cluster-limitations.html" title="25.2.7 Known Limitations of NDB Cluster">
Section 25.2.7, “Known Limitations of NDB Cluster”
</a>
, and
<a class="xref" href="partitioning-limitations-storage-engines.html" title="26.6.2 Partitioning Limitations Relating to Storage Engines">
Section 26.6.2, “Partitioning Limitations Relating to Storage Engines”
</a>
.
</p>
<p>
<a name="mysql-cluster-nodes-groups-replica">
</a>
<b>
Fragment replica.
</b>
This is a copy of a cluster partition. Each node in a node group
stores a fragment replica. Also sometimes known as a
<span class="firstterm">
partition replica
</span>
. The
number of fragment replicas is equal to the number of nodes per
node group.
</p>
<p>
A fragment replica belongs entirely to a single node; a node can
(and usually does) store several fragment replicas.
</p>
<p>
The following diagram illustrates an NDB Cluster with four data
nodes running
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
, arranged in two node groups
of two nodes each; nodes 1 and 2 belong to node group 0, and nodes
3 and 4 belong to node group 1.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Only data nodes are shown here; although a working NDB Cluster
requires an
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
process for cluster
management and at least one SQL node to access the data stored
by the cluster, these have been omitted from the figure for
clarity.
</p>
</div>
<div class="figure">
<a name="fig-mysql-cluster-2-node-groups">
</a>
<p class="title">
<b>
Figure 25.2 NDB Cluster with Two Node Groups
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt="Content is described in the surrounding text." src="images/fragment-replicas-groups-1-1.png" style="width: 100%; max-width: 504px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
<p>
The data stored by the cluster is divided into four partitions,
numbered 0, 1, 2, and 3. Each partition is stored—in
multiple copies—on the same node group. Partitions are
stored on alternate node groups as follows:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Partition 0 is stored on node group 0; a
<span class="firstterm">
primary fragment replica
</span>
(primary copy) is stored on node 1, and a
<span class="firstterm">
backup fragment replica
</span>
(backup copy of the partition) is stored on node 2.
</p>
</li>
<li class="listitem">
<p>
Partition 1 is stored on the other node group (node group 1);
this partition's primary fragment replica is on node 3,
and its backup fragment replica is on node 4.
</p>
</li>
<li class="listitem">
<p>
Partition 2 is stored on node group 0. However, the placing of
its two fragment replicas is reversed from that of Partition
0; for Partition 2, the primary fragment replica is stored on
node 2, and the backup on node 1.
</p>
</li>
<li class="listitem">
<p>
Partition 3 is stored on node group 1, and the placement of
its two fragment replicas are reversed from those of partition
1. That is, its primary fragment replica is located on node 4,
with the backup on node 3.
</p>
</li>
</ul>
</div>
<p>
What this means regarding the continued operation of an NDB
Cluster is this: so long as each node group participating in the
cluster has at least one node operating, the cluster has a
complete copy of all data and remains viable. This is illustrated
in the next diagram.
</p>
<div class="figure">
<a name="fig-mysql-cluster-nodes-required-2x2">
</a>
<p class="title">
<b>
Figure 25.3 Nodes Required for a 2x2 NDB Cluster
</b>
</p>
<div class="figure-contents">
<div class="mediaobject">
<img alt="Content is described in the surrounding text." src="images/replicas-groups-1-2.png" style="width: 100%; max-width: 344px;"/>
</div>
</div>
</div>
<br class="figure-break"/>
<p>
In this example, the cluster consists of two node groups each
consisting of two data nodes. Each data node is running an
instance of
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
. Any combination of at least
one node from node group 0 and at least one node from node group 1
is sufficient to keep the cluster
<span class="quote">
“
<span class="quote">
alive
</span>
”
</span>
. However,
if both nodes from a single node group fail, the combination
consisting of the remaining two nodes in the other node group is
not sufficient. In this situation, the cluster has lost an entire
partition and so can no longer provide access to a complete set of
all NDB Cluster data.
</p>
<p>
The maximum number of node groups supported for a single NDB
Cluster instance is 48.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/programs-miscellaneous.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="programs-miscellaneous">
</a>
6.8 Miscellaneous Programs
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="perror.html">
6.8.1 perror — Display MySQL Error Message Information
</a>
</span>
</dt>
</dl>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-format-path.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-format-path">
</a>
30.4.5.4 The format_path() Function
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045060998032">
</a>
<a class="indexterm" name="idm46045060996576">
</a>
<p>
Given a path name, returns the modified path name after
replacing subpaths that match the values of the following
system variables, in order:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa14385501"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">datadir
tmpdir
replica_load_tmpdir
innodb_data_home_dir
innodb_log_group_home_dir
innodb_undo_directory
basedir</code></pre>
</div>
<p>
A value that matches the value of system variable
<em class="replaceable">
<code>
sysvar
</code>
</em>
is replaced with the string
<code class="literal">
@@GLOBAL.
<em class="replaceable">
<code>
sysvar
</code>
</em>
</code>
.
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-path-parameters">
</a>
Parameters
</h5>
</div>
</div>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
path VARCHAR(512)
</code>
: The path name to
format.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-path-return-value">
</a>
Return Value
</h5>
</div>
</div>
</div>
<p>
A
<code class="literal">
VARCHAR(512) CHARACTER SET utf8mb3
</code>
value.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-path-example">
</a>
Example
</h5>
</div>
</div>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa57270244"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> sys<span class="token punctuation">.</span>format_path<span class="token punctuation">(</span><span class="token string">'/usr/local/mysql/data/world/City.ibd'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> sys.format_path('/usr/local/mysql/data/world/City.ibd') <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@datadir/world/City.ibd <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/option-files.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="option-files">
</a>
6.2.2.2 Using Option Files
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045324171552">
</a>
<a class="indexterm" name="idm46045324170480">
</a>
<a class="indexterm" name="idm46045324169408">
</a>
<a class="indexterm" name="idm46045324167920">
</a>
<a class="indexterm" name="idm46045324166432">
</a>
<a class="indexterm" name="idm46045324165360">
</a>
<a class="indexterm" name="idm46045324163872">
</a>
<a class="indexterm" name="idm46045324162784">
</a>
<a class="indexterm" name="idm46045324161296">
</a>
<a class="indexterm" name="idm46045324160208">
</a>
<p>
Most MySQL programs can read startup options from option files
(sometimes called configuration files). Option files provide a
convenient way to specify commonly used options so that they
need not be entered on the command line each time you run a
program.
</p>
<p>
To determine whether a program reads option files, invoke it
with the
<code class="option">
--help
</code>
option. (For
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
, use
<a class="link" href="server-options.html#option_mysqld_verbose">
<code class="option">
--verbose
</code>
</a>
and
<a class="link" href="server-options.html#option_mysqld_help">
<code class="option">
--help
</code>
</a>
.) If the program reads
option files, the help message indicates which files it looks
for and which option groups it recognizes.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
A MySQL program started with the
<code class="option">
--no-defaults
</code>
option reads no option files
other than
<code class="filename">
.mylogin.cnf
</code>
.
</p>
<p>
A server started with the
<a class="link" href="server-system-variables.html#sysvar_persisted_globals_load">
<code class="literal">
persisted_globals_load
</code>
</a>
system
variable disabled does not read
<code class="filename">
mysqld-auto.cnf
</code>
.
</p>
</div>
<p>
Many option files are plain text files, created using any text
editor. The exceptions are:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The
<code class="filename">
.mylogin.cnf
</code>
file that contains
login path options. This is an encrypted file created by the
<a class="link" href="mysql-config-editor.html" title="6.6.7 mysql_config_editor — MySQL Configuration Utility">
<span class="command">
<strong>
mysql_config_editor
</strong>
</span>
</a>
utility. See
<a class="xref" href="mysql-config-editor.html" title="6.6.7 mysql_config_editor — MySQL Configuration Utility">
Section 6.6.7, “mysql_config_editor — MySQL Configuration Utility”
</a>
. A
<span class="quote">
“
<span class="quote">
login
path
</span>
”
</span>
is an option group that permits only certain
options:
<code class="option">
host
</code>
,
<code class="option">
user
</code>
,
<code class="option">
password
</code>
,
<code class="option">
port
</code>
and
<code class="option">
socket
</code>
. Client programs specify which login
path to read from
<code class="filename">
.mylogin.cnf
</code>
using
the
<a class="link" href="option-file-options.html#option_general_login-path">
<code class="option">
--login-path
</code>
</a>
option.
</p>
<p>
To specify an alternative login path file name, set the
<code class="literal">
MYSQL_TEST_LOGIN_FILE
</code>
environment
variable. This variable is used by the
<span class="command">
<strong>
mysql-test-run.pl
</strong>
</span>
testing utility, but
also is recognized by
<a class="link" href="mysql-config-editor.html" title="6.6.7 mysql_config_editor — MySQL Configuration Utility">
<span class="command">
<strong>
mysql_config_editor
</strong>
</span>
</a>
and by MySQL clients such as
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
,
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin
</strong>
</span>
</a>
, and so forth.
</p>
</li>
<li class="listitem">
<p>
The
<code class="filename">
mysqld-auto.cnf
</code>
file in the data
directory. This JSON-format file contains persisted system
variable settings. It is created by the server upon
execution of
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
or
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
statements. See
<a class="xref" href="persisted-system-variables.html" title="7.1.9.3 Persisted System Variables">
Section 7.1.9.3, “Persisted System Variables”
</a>
. Management of
<code class="filename">
mysqld-auto.cnf
</code>
should be left to the
server and not performed manually.
</p>
</li>
</ul>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="option-files.html#option-file-order" title="Option File Processing Order">
Option File Processing Order
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="option-files.html#option-file-syntax" title="Option File Syntax">
Option File Syntax
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="option-files.html#option-file-inclusions" title="Option File Inclusions">
Option File Inclusions
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="option-file-order">
</a>
Option File Processing Order
</h5>
</div>
</div>
</div>
<p>
MySQL looks for option files in the order described in the
following discussion and reads any that exist. If an option
file you want to use does not exist, create it using the
appropriate method, as just discussed.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
For information about option files used with NDB Cluster
programs, see
<a class="xref" href="mysql-cluster-configuration.html" title="25.4 Configuration of NDB Cluster">
Section 25.4, “Configuration of NDB Cluster”
</a>
.
</p>
</div>
<p>
On Windows, MySQL programs read startup options from the files
shown in the following table, in the specified order (files
listed first are read first, files read later take
precedence).
</p>
<div class="table">
<a name="option-files-windows">
</a>
<p class="title">
<b>
Table 6.1 Option Files Read on Windows Systems
</b>
</p>
<div class="table-contents">
<table summary="Option files read by MySQL programs on Windows systems.">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<thead>
<tr>
<th>
File Name
</th>
<th>
Purpose
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="filename">
<code class="literal">
%WINDIR%
</code>
\my.ini
</code>
,
<code class="filename">
<code class="literal">
%WINDIR%
</code>
\my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="filename">
C:\my.ini
</code>
,
<code class="filename">
C:\my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
BASEDIR
</code>
</em>
\my.ini
</code>
,
<code class="filename">
<em class="replaceable">
<code>
BASEDIR
</code>
</em>
\my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="literal">
defaults-extra-file
</code>
</td>
<td>
The file specified with
<a class="link" href="option-file-options.html#option_general_defaults-extra-file">
<code class="option">
--defaults-extra-file
</code>
</a>
,
if any
</td>
</tr>
<tr>
<td>
<code class="filename">
<code class="literal">
%APPDATA%
</code>
\MySQL\.mylogin.cnf
</code>
</td>
<td>
Login path options (clients only)
</td>
</tr>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
DATADIR
</code>
</em>
\mysqld-auto.cnf
</code>
</td>
<td>
System variables persisted with
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
or
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
(server only)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
In the preceding table,
<code class="literal">
%WINDIR%
</code>
represents
the location of your Windows directory. This is commonly
<code class="filename">
C:\WINDOWS
</code>
. Use the following command to
determine its exact location from the value of the
<code class="literal">
WINDIR
</code>
environment variable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa56669563"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">C:\></span><span class="token command"> echo</span> %WINDIR%</code></pre>
</div>
<p>
<code class="literal">
%APPDATA%
</code>
represents the value of the
Windows application data directory. Use the following command
to determine its exact location from the value of the
<code class="literal">
APPDATA
</code>
environment variable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa44855089"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">C:\></span><span class="token command"> echo</span> %APPDATA%</code></pre>
</div>
<p>
<em class="replaceable">
<code>
BASEDIR
</code>
</em>
represents the MySQL base
installation directory. When MySQL 8.4 has been
installed using the MSI, this is typically
<code class="filename">
C:\
<em class="replaceable">
<code>
PROGRAMDIR
</code>
</em>
\MySQL\MySQL
Server 8.4
</code>
in which
<em class="replaceable">
<code>
PROGRAMDIR
</code>
</em>
represents the programs
directory (usually
<code class="filename">
Program Files
</code>
for
English-language versions of Windows).
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
Although MySQL Configurator places most files under
<em class="replaceable">
<code>
PROGRAMDIR
</code>
</em>
, it installs
<code class="filename">
my.ini
</code>
under the
<code class="filename">
C:\ProgramData\MySQL\MySQL Server
8.4\
</code>
directory by default.
</p>
</div>
<p>
<em class="replaceable">
<code>
DATADIR
</code>
</em>
represents the MySQL data
directory. As used to find
<code class="filename">
mysqld-auto.cnf
</code>
, its default value is the
data directory location built in when MySQL was compiled, but
can be changed by
<a class="link" href="server-system-variables.html#sysvar_datadir">
<code class="option">
--datadir
</code>
</a>
specified as an option-file or command-line option processed
before
<code class="filename">
mysqld-auto.cnf
</code>
is processed.
</p>
<p>
On Unix and Unix-like systems, MySQL programs read startup
options from the files shown in the following table, in the
specified order (files listed first are read first, files read
later take precedence).
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
On Unix platforms, MySQL ignores configuration files that
are world-writable. This is intentional as a security
measure.
</p>
</div>
<a class="indexterm" name="idm46045324071648">
</a>
<a class="indexterm" name="idm46045324070576">
</a>
<div class="table">
<a name="option-files-unix">
</a>
<p class="title">
<b>
Table 6.2 Option Files Read on Unix and Unix-Like Systems
</b>
</p>
<div class="table-contents">
<table summary="Option files read by MySQL programs on Unix and Unix-like systems.">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<thead>
<tr>
<th>
File Name
</th>
<th>
Purpose
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="filename">
/etc/my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="filename">
/etc/mysql/my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
SYSCONFDIR
</code>
</em>
/my.cnf
</code>
</td>
<td>
Global options
</td>
</tr>
<tr>
<td>
<code class="filename">
$MYSQL_HOME/my.cnf
</code>
</td>
<td>
Server-specific options (server only)
</td>
</tr>
<tr>
<td>
<code class="literal">
defaults-extra-file
</code>
</td>
<td>
The file specified with
<a class="link" href="option-file-options.html#option_general_defaults-extra-file">
<code class="option">
--defaults-extra-file
</code>
</a>
,
if any
</td>
</tr>
<tr>
<td>
<code class="filename">
~/.my.cnf
</code>
</td>
<td>
User-specific options
</td>
</tr>
<tr>
<td>
<code class="filename">
~/.mylogin.cnf
</code>
</td>
<td>
User-specific login path options (clients only)
</td>
</tr>
<tr>
<td>
<code class="filename">
<em class="replaceable">
<code>
DATADIR
</code>
</em>
/mysqld-auto.cnf
</code>
</td>
<td>
System variables persisted with
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST
</code>
</a>
or
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
PERSIST_ONLY
</code>
</a>
(server only)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
In the preceding table,
<code class="filename">
~
</code>
represents the
current user's home directory (the value of
<code class="literal">
$HOME
</code>
).
</p>
<p>
<em class="replaceable">
<code>
SYSCONFDIR
</code>
</em>
represents the directory
specified with the
<a class="link" href="source-configuration-options.html#option_cmake_sysconfdir">
<code class="option">
SYSCONFDIR
</code>
</a>
option to
<span class="command">
<strong>
CMake
</strong>
</span>
when MySQL was built. By
default, this is the
<code class="filename">
etc
</code>
directory
located under the compiled-in installation directory.
</p>
<p>
<code class="literal">
MYSQL_HOME
</code>
is an environment variable
containing the path to the directory in which the
server-specific
<code class="filename">
my.cnf
</code>
file resides. If
<code class="literal">
MYSQL_HOME
</code>
is not set and you start the
server using the
<a class="link" href="mysqld-safe.html" title="6.3.2 mysqld_safe — MySQL Server Startup Script">
<span class="command">
<strong>
mysqld_safe
</strong>
</span>
</a>
program,
<a class="link" href="mysqld-safe.html" title="6.3.2 mysqld_safe — MySQL Server Startup Script">
<span class="command">
<strong>
mysqld_safe
</strong>
</span>
</a>
sets it to
<em class="replaceable">
<code>
BASEDIR
</code>
</em>
, the MySQL base
installation directory.
</p>
<p>
<em class="replaceable">
<code>
DATADIR
</code>
</em>
represents the MySQL data
directory. As used to find
<code class="filename">
mysqld-auto.cnf
</code>
, its default value is the
data directory location built in when MySQL was compiled, but
can be changed by
<a class="link" href="server-system-variables.html#sysvar_datadir">
<code class="option">
--datadir
</code>
</a>
specified as an option-file or command-line option processed
before
<code class="filename">
mysqld-auto.cnf
</code>
is processed.
</p>
<p>
If multiple instances of a given option are found, the last
instance takes precedence, with one exception: For
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
, the
<span class="emphasis">
<em>
first
</em>
</span>
instance of the
<a class="link" href="server-options.html#option_mysqld_user">
<code class="option">
--user
</code>
</a>
option
is used as a security precaution, to prevent a user specified
in an option file from being overridden on the command line.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="option-file-syntax">
</a>
Option File Syntax
</h5>
</div>
</div>
</div>
<p>
The following description of option file syntax applies to
files that you edit manually. This excludes
<code class="filename">
.mylogin.cnf
</code>
, which is created using
<a class="link" href="mysql-config-editor.html" title="6.6.7 mysql_config_editor — MySQL Configuration Utility">
<span class="command">
<strong>
mysql_config_editor
</strong>
</span>
</a>
and is encrypted, and
<code class="filename">
mysqld-auto.cnf
</code>
, which the server creates
in JSON format.
</p>
<p>
Any long option that may be given on the command line when
running a MySQL program can be given in an option file as
well. To get the list of available options for a program, run
it with the
<code class="option">
--help
</code>
option. (For
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
, use
<a class="link" href="server-options.html#option_mysqld_verbose">
<code class="option">
--verbose
</code>
</a>
and
<a class="link" href="server-options.html#option_mysqld_help">
<code class="option">
--help
</code>
</a>
.)
</p>
<p>
The syntax for specifying options in an option file is similar
to command-line syntax (see
<a class="xref" href="command-line-options.html" title="6.2.2.1 Using Options on the Command Line">
Section 6.2.2.1, “Using Options on the Command Line”
</a>
). However, in an option
file, you omit the leading two dashes from the option name and
you specify only one option per line. For example,
<code class="option">
--quick
</code>
and
<code class="option">
--host=localhost
</code>
on the command line should be specified as
<code class="literal">
quick
</code>
and
<code class="literal">
host=localhost
</code>
on separate lines in an option file. To specify an option of
the form
<code class="option">
--loose-
<em class="replaceable">
<code>
opt_name
</code>
</em>
</code>
in an option file, write it as
<code class="literal">
loose-
<em class="replaceable">
<code>
opt_name
</code>
</em>
</code>
.
</p>
<p>
Empty lines in option files are ignored. Nonempty lines can
take any of the following forms:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
#
<em class="replaceable">
<code>
comment
</code>
</em>
</code>
,
<code class="literal">
;
<em class="replaceable">
<code>
comment
</code>
</em>
</code>
</p>
<p>
Comment lines start with
<code class="literal">
#
</code>
or
<code class="literal">
;
</code>
. A
<code class="literal">
#
</code>
comment can
start in the middle of a line as well.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[
<em class="replaceable">
<code>
group
</code>
</em>
]
</code>
</p>
<p>
<em class="replaceable">
<code>
group
</code>
</em>
is the name of the
program or group for which you want to set options. After
a group line, any option-setting lines apply to the named
group until the end of the option file or another group
line is given. Option group names are not case-sensitive.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
<em class="replaceable">
<code>
opt_name
</code>
</em>
</code>
</p>
<p>
This is equivalent to
<code class="option">
--
<em class="replaceable">
<code>
opt_name
</code>
</em>
</code>
on
the command line.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
<em class="replaceable">
<code>
opt_name
</code>
</em>
=
<em class="replaceable">
<code>
value
</code>
</em>
</code>
</p>
<p>
This is equivalent to
<code class="option">
--
<em class="replaceable">
<code>
opt_name
</code>
</em>
=
<em class="replaceable">
<code>
value
</code>
</em>
</code>
on the command line. In an option file, you can have
spaces around the
<code class="literal">
=
</code>
character,
something that is not true on the command line. The value
optionally can be enclosed within single quotation marks
or double quotation marks, which is useful if the value
contains a
<code class="literal">
#
</code>
comment character.
</p>
</li>
</ul>
</div>
<p>
Leading and trailing spaces are automatically deleted from
option names and values.
</p>
<a class="indexterm" name="idm46045323988176">
</a>
<a class="indexterm" name="idm46045323986688">
</a>
<p>
You can use the escape sequences
<code class="literal">
\b
</code>
,
<code class="literal">
\t
</code>
,
<code class="literal">
\n
</code>
,
<code class="literal">
\r
</code>
,
<code class="literal">
\\
</code>
, and
<code class="literal">
\s
</code>
in option values to represent the
backspace, tab, newline, carriage return, backslash, and space
characters. In option files, these escaping rules apply:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
A backslash followed by a valid escape sequence character
is converted to the character represented by the sequence.
For example,
<code class="literal">
\s
</code>
is converted to a
space.
</p>
</li>
<li class="listitem">
<p>
A backslash not followed by a valid escape sequence
character remains unchanged. For example,
<code class="literal">
\S
</code>
is retained as is.
</p>
</li>
</ul>
</div>
<p>
The preceding rules mean that a literal backslash can be given
as
<code class="literal">
\\
</code>
, or as
<code class="literal">
\
</code>
if it is
not followed by a valid escape sequence character.
</p>
<p>
The rules for escape sequences in option files differ slightly
from the rules for escape sequences in string literals in SQL
statements. In the latter context, if
<span class="quote">
“
<span class="quote">
<em class="replaceable">
<code>
x
</code>
</em>
</span>
”
</span>
is not a valid
escape sequence character,
<code class="literal">
\
<em class="replaceable">
<code>
x
</code>
</em>
</code>
becomes
<span class="quote">
“
<span class="quote">
<em class="replaceable">
<code>
x
</code>
</em>
</span>
”
</span>
rather than
<code class="literal">
\
<em class="replaceable">
<code>
x
</code>
</em>
</code>
. See
<a class="xref" href="string-literals.html" title="11.1.1 String Literals">
Section 11.1.1, “String Literals”
</a>
.
</p>
<a class="indexterm" name="idm46045323970144">
</a>
<a class="indexterm" name="idm46045323968656">
</a>
<p>
The escaping rules for option file values are especially
pertinent for Windows path names, which use
<code class="literal">
\
</code>
as a path name separator. A separator in
a Windows path name must be written as
<code class="literal">
\\
</code>
if it is followed by an escape sequence character. It can be
written as
<code class="literal">
\\
</code>
or
<code class="literal">
\
</code>
if it
is not. Alternatively,
<code class="literal">
/
</code>
may be used in
Windows path names and is treated as
<code class="literal">
\
</code>
.
Suppose that you want to specify a base directory of
<code class="filename">
C:\Program Files\MySQL\MySQL Server
8.4
</code>
in an option file. This can be
done several ways. Some examples:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa67645995"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>"C:\Program Files\MySQL\MySQL Server 8.4"</span>
<span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>"C:\\Program Files\\MySQL\\MySQL Server 8.4"</span>
<span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>"C:/Program Files/MySQL/MySQL Server 8.4"</span>
<span class="token constant">basedir</span><span class="token attr-value"><span class="token punctuation">=</span>C:\\Program\sFiles\\MySQL\\MySQL\sServer\s8.4</span></code></pre>
</div>
<p>
If an option group name is the same as a program name, options
in the group apply specifically to that program. For example,
the
<code class="literal">
[mysqld]
</code>
and
<code class="literal">
[mysql]
</code>
groups apply to the
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
server and the
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
client program, respectively.
</p>
<p>
The
<code class="literal">
[client]
</code>
option group is read by all
client programs provided in MySQL distributions (but
<span class="emphasis">
<em>
not
</em>
</span>
by
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
). To
understand how third-party client programs that use the C API
can use option files, see the C API documentation at
<a class="ulink" href="/doc/c-api/8.4/en/mysql-options.html" target="_top">
mysql_options()
</a>
.
</p>
<p>
The
<code class="literal">
[client]
</code>
group enables you to specify
options that apply to all clients. For example,
<code class="literal">
[client]
</code>
is the appropriate group to use to
specify the password for connecting to the server. (But make
sure that the option file is accessible only by yourself, so
that other people cannot discover your password.) Be sure not
to put an option in the
<code class="literal">
[client]
</code>
group
unless it is recognized by
<span class="emphasis">
<em>
all
</em>
</span>
client
programs that you use. Programs that do not understand the
option quit after displaying an error message if you try to
run them.
</p>
<p>
List more general option groups first and more specific groups
later. For example, a
<code class="literal">
[client]
</code>
group is
more general because it is read by all client programs,
whereas a
<code class="literal">
[mysqldump]
</code>
group is read only by
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
. Options specified later override
options specified earlier, so putting the option groups in the
order
<code class="literal">
[client]
</code>
,
<code class="literal">
[mysqldump]
</code>
enables
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
-specific options to override
<code class="literal">
[client]
</code>
options.
</p>
<p>
Here is a typical global option file:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa23520600"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[client]</span>
<span class="token constant">port</span><span class="token attr-value"><span class="token punctuation">=</span>3306</span>
<span class="token constant">socket</span><span class="token attr-value"><span class="token punctuation">=</span>/tmp/mysql.sock</span>
<span class="token selector">[mysqld]</span>
<span class="token constant">port</span><span class="token attr-value"><span class="token punctuation">=</span>3306</span>
<span class="token constant">socket</span><span class="token attr-value"><span class="token punctuation">=</span>/tmp/mysql.sock</span>
<span class="token constant">key_buffer_size</span><span class="token attr-value"><span class="token punctuation">=</span>16M</span>
<span class="token constant">max_allowed_packet</span><span class="token attr-value"><span class="token punctuation">=</span>128M</span>
<span class="token selector">[mysqldump]</span>
<span class="token constant">quick</span></code></pre>
</div>
<p>
Here is a typical user option file:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa63509956"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[client]</span>
<span class="token comment" spellcheck="true"># The following password is sent to all standard MySQL clients</span>
<span class="token constant">password</span><span class="token attr-value"><span class="token punctuation">=</span>"my password"</span>
<span class="token selector">[mysql]</span>
<span class="token constant">no-auto-rehash</span>
<span class="token constant">connect_timeout</span><span class="token attr-value"><span class="token punctuation">=</span>2</span></code></pre>
</div>
<p>
To create option groups to be read only by
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
servers from specific MySQL release
series, use groups with names of
<code class="literal">
[mysqld-8.3]
</code>
,
<code class="literal">
[mysqld-8.4]
</code>
, and so forth.
The following group indicates that the
<a class="link" href="server-system-variables.html#sysvar_sql_mode">
<code class="literal">
sql_mode
</code>
</a>
setting should be
used only by MySQL servers with 8.4.x version
numbers:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa96218377"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqld-8.4]</span>
<span class="token constant">sql_mode</span><span class="token attr-value"><span class="token punctuation">=</span>TRADITIONAL</span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="option-file-inclusions">
</a>
Option File Inclusions
</h5>
</div>
</div>
</div>
<p>
It is possible to use
<code class="literal">
!include
</code>
directives
in option files to include other option files and
<code class="literal">
!includedir
</code>
to search specific directories
for option files. For example, to include the
<code class="filename">
/home/mydir/myopt.cnf
</code>
file, use the
following directive:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa11487548"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">!include /home/mydir/myopt.cnf</code></pre>
</div>
<p>
To search the
<code class="filename">
/home/mydir
</code>
directory and
read option files found there, use this directive:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa69297318"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">!includedir /home/mydir</code></pre>
</div>
<p>
MySQL makes no guarantee about the order in which option files
in the directory are read.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Any files to be found and included using the
<code class="literal">
!includedir
</code>
directive on Unix operating
systems
<span class="emphasis">
<em>
must
</em>
</span>
have file names ending in
<code class="filename">
.cnf
</code>
. On Windows, this directive checks
for files with the
<code class="filename">
.ini
</code>
or
<code class="filename">
.cnf
</code>
extension.
</p>
</div>
<p>
Write the contents of an included option file like any other
option file. That is, it should contain groups of options,
each preceded by a
<code class="literal">
[
<em class="replaceable">
<code>
group
</code>
</em>
]
</code>
line
that indicates the program to which the options apply.
</p>
<p>
While an included file is being processed, only those options
in groups that the current program is looking for are used.
Other groups are ignored. Suppose that a
<code class="filename">
my.cnf
</code>
file contains this line:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa70626475"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">!include /home/mydir/myopt.cnf</code></pre>
</div>
<p>
And suppose that
<code class="filename">
/home/mydir/myopt.cnf
</code>
looks like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa39867180"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token selector">[mysqladmin]</span>
<span class="token constant">force</span>
<span class="token selector">[mysqld]</span>
<span class="token constant">key_buffer_size</span><span class="token attr-value"><span class="token punctuation">=</span>16M</span></code></pre>
</div>
<p>
If
<code class="filename">
my.cnf
</code>
is processed by
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
, only the
<code class="literal">
[mysqld]
</code>
group in
<code class="filename">
/home/mydir/myopt.cnf
</code>
is used. If the
file is processed by
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin
</strong>
</span>
</a>
, only the
<code class="literal">
[mysqladmin]
</code>
group is used. If the file is
processed by any other program, no options in
<code class="filename">
/home/mydir/myopt.cnf
</code>
are used.
</p>
<p>
The
<code class="literal">
!includedir
</code>
directive is processed
similarly except that all option files in the named directory
are read.
</p>
<p>
If an option file contains
<code class="literal">
!include
</code>
or
<code class="literal">
!includedir
</code>
directives, files named by
those directives are processed whenever the option file is
processed, no matter where they appear in the file.
</p>
<p>
For inclusion directives to work, the file path should not be
specified within quotes and should have no escape sequences.
For example, the following statements provided in
<code class="filename">
my.ini
</code>
read the option file
<code class="filename">
myopts.ini
</code>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa23714900"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini">!include C:/ProgramData/MySQL/MySQL Server/myopts.ini
!include C:\ProgramData\MySQL\MySQL Server\myopts.ini
!include C:\\ProgramData\\MySQL\\MySQL Server\\myopts.ini</code></pre>
</div>
<p>
On Windows, if
<code class="literal">
!include
<em class="replaceable">
<code>
/path/to/extra.ini
</code>
</em>
</code>
is the
last line in the file, make sure that a newline is appended at
the end; otherwise, the line is ignored.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-ps-thread-account.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-ps-thread-account">
</a>
30.4.5.14 The ps_thread_account() Function
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045060801296">
</a>
<a class="indexterm" name="idm46045060799824">
</a>
<p>
Given a Performance Schema thread ID, returns the
<code class="literal">
<em class="replaceable">
<code>
user_name
</code>
</em>
@
<em class="replaceable">
<code>
host_name
</code>
</em>
</code>
account associated with the thread.
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-thread-account-parameters">
</a>
Parameters
</h5>
</div>
</div>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
in_thread_id BIGINT UNSIGNED
</code>
: The
thread ID for which to return the account. The value
should match the
<code class="literal">
THREAD_ID
</code>
column
from some Performance Schema
<a class="link" href="performance-schema-threads-table.html" title="29.12.22.8 The threads Table">
<code class="literal">
threads
</code>
</a>
table row.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-thread-account-return-value">
</a>
Return Value
</h5>
</div>
</div>
</div>
<p>
A
<code class="literal">
TEXT
</code>
value.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-thread-account-example">
</a>
Example
</h5>
</div>
</div>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa68096447"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> sys<span class="token punctuation">.</span>ps_thread_account<span class="token punctuation">(</span>sys<span class="token punctuation">.</span>ps_thread_id<span class="token punctuation">(</span><span class="token function">CONNECTION_ID</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> sys.ps_thread_account(sys.ps_thread_id(CONNECTION_ID())) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> root@localhost <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-features-limit.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-features-limit">
</a>
19.5.1.18 Replication and LIMIT
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045135409728">
</a>
<a class="indexterm" name="idm46045135408240">
</a>
<p>
Statement-based replication of
<code class="literal">
LIMIT
</code>
clauses
in
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, and
<a class="link" href="insert-select.html" title="15.2.7.1 INSERT ... SELECT Statement">
<code class="literal">
INSERT ...
SELECT
</code>
</a>
statements is unsafe since the order of the
rows affected is not defined. (Such statements can be replicated
correctly with statement-based replication only if they also
contain an
<code class="literal">
ORDER BY
</code>
clause.) When such a
statement is encountered:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
When using
<code class="literal">
STATEMENT
</code>
mode, a warning that
the statement is not safe for statement-based replication is
now issued.
</p>
<p>
When using
<code class="literal">
STATEMENT
</code>
mode, warnings are
issued for DML statements containing
<code class="literal">
LIMIT
</code>
even when they also have an
<code class="literal">
ORDER BY
</code>
clause (and so are made
deterministic). This is a known issue. (Bug #42851)
</p>
</li>
<li class="listitem">
<p>
When using
<code class="literal">
MIXED
</code>
mode, the statement is
now automatically replicated using row-based mode.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/information-schema-innodb-columns-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="information-schema-innodb-columns-table">
</a>
28.4.9 The INFORMATION_SCHEMA INNODB_COLUMNS Table
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045077149184">
</a>
<p>
The
<a class="link" href="information-schema-innodb-columns-table.html" title="28.4.9 The INFORMATION_SCHEMA INNODB_COLUMNS Table">
<code class="literal">
INNODB_COLUMNS
</code>
</a>
table provides
metadata about
<code class="literal">
InnoDB
</code>
table columns.
</p>
<p>
For related usage information and examples, see
<a class="xref" href="innodb-information-schema-system-tables.html" title="17.15.3 InnoDB INFORMATION_SCHEMA Schema Object Tables">
Section 17.15.3, “InnoDB INFORMATION_SCHEMA Schema Object Tables”
</a>
.
</p>
<p>
The
<a class="link" href="information-schema-innodb-columns-table.html" title="28.4.9 The INFORMATION_SCHEMA INNODB_COLUMNS Table">
<code class="literal">
INNODB_COLUMNS
</code>
</a>
table has these
columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
TABLE_ID
</code>
</p>
<p>
An identifier representing the table associated with the
column; the same value as
<code class="literal">
INNODB_TABLES.TABLE_ID
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
NAME
</code>
</p>
<p>
The name of the column. These names can be uppercase or
lowercase depending on the
<a class="link" href="server-system-variables.html#sysvar_lower_case_table_names">
<code class="literal">
lower_case_table_names
</code>
</a>
setting. There are no special system-reserved names for
columns.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
POS
</code>
</p>
<p>
The ordinal position of the column within the table, starting
from 0 and incrementing sequentially. When a column is
dropped, the remaining columns are reordered so that the
sequence has no gaps. The
<code class="literal">
POS
</code>
value for a
virtual generated column encodes the column sequence number
and ordinal position of the column. For more information, see
the
<code class="literal">
POS
</code>
column description in
<a class="xref" href="information-schema-innodb-virtual-table.html" title="28.4.29 The INFORMATION_SCHEMA INNODB_VIRTUAL Table">
Section 28.4.29, “The INFORMATION_SCHEMA INNODB_VIRTUAL Table”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
MTYPE
</code>
</p>
<p>
Stands for
<span class="quote">
“
<span class="quote">
main type
</span>
”
</span>
. A numeric identifier for
the column type. 1 =
<code class="literal">
VARCHAR
</code>
, 2 =
<code class="literal">
CHAR
</code>
, 3 =
<code class="literal">
FIXBINARY
</code>
, 4 =
<code class="literal">
BINARY
</code>
, 5 =
<code class="literal">
BLOB
</code>
, 6 =
<code class="literal">
INT
</code>
, 7 =
<code class="literal">
SYS_CHILD
</code>
, 8 =
<code class="literal">
SYS
</code>
, 9 =
<code class="literal">
FLOAT
</code>
, 10 =
<code class="literal">
DOUBLE
</code>
, 11 =
<code class="literal">
DECIMAL
</code>
, 12
=
<code class="literal">
VARMYSQL
</code>
, 13 =
<code class="literal">
MYSQL
</code>
,
14 =
<code class="literal">
GEOMETRY
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
PRTYPE
</code>
</p>
<p>
The
<code class="literal">
InnoDB
</code>
<span class="quote">
“
<span class="quote">
precise type
</span>
”
</span>
, a
binary value with bits representing MySQL data type, character
set code, and nullability.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
LEN
</code>
</p>
<p>
The column length, for example 4 for
<code class="literal">
INT
</code>
and 8 for
<code class="literal">
BIGINT
</code>
. For character columns in
multibyte character sets, this length value is the maximum
length in bytes needed to represent a definition such as
<code class="literal">
VARCHAR(
<em class="replaceable">
<code>
N
</code>
</em>
)
</code>
; that
is, it might be
<code class="literal">
2*
<em class="replaceable">
<code>
N
</code>
</em>
</code>
,
<code class="literal">
3*
<em class="replaceable">
<code>
N
</code>
</em>
</code>
, and so on
depending on the character encoding.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
HAS_DEFAULT
</code>
</p>
<p>
A boolean value indicating whether a column that was added
instantly using
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE ...
ADD COLUMN
</code>
</a>
with
<code class="literal">
ALGORITHM=INSTANT
</code>
has a default value. All columns added instantly have a
default value, which makes this column an indicator of whether
the column was added instantly.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
DEFAULT_VALUE
</code>
</p>
<p>
The initial default value of a column that was added instantly
using
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
... ADD COLUMN
</code>
</a>
with
<code class="literal">
ALGORITHM=INSTANT
</code>
. If the default value is
<code class="literal">
NULL
</code>
or was not specified, this column
reports
<code class="literal">
NULL
</code>
. An explicitly specified
non-
<code class="literal">
NULL
</code>
default value is shown in an
internal binary format. Subsequent modifications of the column
default value do not change the value reported by this column.
</p>
</li>
</ul>
</div>
<h4>
<a name="idm46045077099136">
</a>
Example
</h4>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa86344422"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span>INNODB_COLUMNS <span class="token keyword">where</span> TABLE_ID <span class="token operator">=</span> <span class="token number">71</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
TABLE_ID<span class="token punctuation">:</span> 71
NAME<span class="token punctuation">:</span> col1
POS<span class="token punctuation">:</span> 0
MTYPE<span class="token punctuation">:</span> 6
PRTYPE<span class="token punctuation">:</span> 1027
LEN<span class="token punctuation">:</span> 4
HAS_DEFAULT<span class="token punctuation">:</span> 0
DEFAULT_VALUE<span class="token punctuation">:</span> NULL
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 2. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
TABLE_ID<span class="token punctuation">:</span> 71
NAME<span class="token punctuation">:</span> col2
POS<span class="token punctuation">:</span> 1
MTYPE<span class="token punctuation">:</span> 2
PRTYPE<span class="token punctuation">:</span> 524542
LEN<span class="token punctuation">:</span> 10
HAS_DEFAULT<span class="token punctuation">:</span> 0
DEFAULT_VALUE<span class="token punctuation">:</span> NULL
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 3. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
TABLE_ID<span class="token punctuation">:</span> 71
NAME<span class="token punctuation">:</span> col3
POS<span class="token punctuation">:</span> 2
MTYPE<span class="token punctuation">:</span> 1
PRTYPE<span class="token punctuation">:</span> 524303
LEN<span class="token punctuation">:</span> 10
HAS_DEFAULT<span class="token punctuation">:</span> 0
DEFAULT_VALUE<span class="token punctuation">:</span> NULL</span></code></pre>
</div>
<h4>
<a name="idm46045077096128">
</a>
Notes
</h4>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
You must have the
<a class="link" href="privileges-provided.html#priv_process">
<code class="literal">
PROCESS
</code>
</a>
privilege to query this table.
</p>
</li>
<li class="listitem">
<p>
Use the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-columns-table.html" title="28.3.8 The INFORMATION_SCHEMA COLUMNS Table">
<code class="literal">
COLUMNS
</code>
</a>
table or the
<a class="link" href="show-columns.html" title="15.7.7.6 SHOW COLUMNS Statement">
<code class="literal">
SHOW COLUMNS
</code>
</a>
statement to view
additional information about the columns of this table,
including data types and default values.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/updating-yum-repo.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="updating-yum-repo">
</a>
3.8 Upgrading MySQL with the MySQL Yum Repository
</h2>
</div>
</div>
</div>
<a class="indexterm" name="idm46045325983968">
</a>
<a class="indexterm" name="idm46045325982928">
</a>
<p>
For supported Yum-based platforms (see
<a class="xref" href="linux-installation-yum-repo.html" title="2.5.1 Installing MySQL on Linux Using the MySQL Yum Repository">
Section 2.5.1, “Installing MySQL on Linux Using the MySQL Yum Repository”
</a>
, for a list), you
can perform an in-place upgrade for MySQL (that is, replacing the
old version and then running the new version using the old data
files) with the MySQL Yum repository.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Notes
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
An innovation series, such as MySQL
9.1, is in a separate track than an
LTS series, such as MySQL 8.4. The LTS
series is active by default.
</p>
</li>
<li class="listitem">
<p>
Before performing any update to MySQL, follow carefully the
instructions in
<a class="xref" href="upgrading.html" title="Chapter 3 Upgrading MySQL">
Chapter 3,
<i>
Upgrading MySQL
</i>
</a>
. Among other
instructions discussed there, it is especially important to
back up your database before the update.
</p>
</li>
<li class="listitem">
<p>
The following instructions assume you have installed MySQL
with the MySQL Yum repository or with an RPM package
directly downloaded from
<a class="ulink" href="https://dev.mysql.com/downloads/" target="_top">
MySQL Developer
Zone's MySQL Download page
</a>
; if that is not the
case, following the instructions in
<a class="xref" href="linux-installation-yum-repo.html#linux-installation-yum-repo-replace-third-party" title="Replacing a Native Third-Party Distribution of MySQL">
Replacing a Native Third-Party Distribution of MySQL
</a>
.
</p>
</li>
</ul>
</div>
</div>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<h3>
<a name="idm46045325972064">
</a>
Selecting a Target Series
</h3>
<p>
By default, the MySQL Yum repository updates MySQL to the
latest version in the release track you have chosen during
installation (see
<a class="xref" href="linux-installation-yum-repo.html#yum-repo-select-series" title="Selecting a Release Series">
Selecting a Release Series
</a>
for
details), which means, for example, a 8.0.x
installation is
<span class="emphasis">
<em>
not
</em>
</span>
updated to a
8.4.x release automatically. To update to
another release series, you must first disable the
subrepository for the series that has been selected (by
default, or by yourself) and enable the subrepository for your
target series. To do that, see the general instructions given
in
<a class="xref" href="linux-installation-yum-repo.html#yum-repo-select-series" title="Selecting a Release Series">
Selecting a Release Series
</a>
for editing the
subrepository entries in the
<code class="filename">
/etc/yum.repos.d/mysql-community.repo
</code>
file.
</p>
<p>
As a general rule, to upgrade from one bugfix series to
another, go to the next bugfix series rather than skipping a
bugfix series. For example, if you are currently running MySQL
5.7 and wish to upgrade to MySQL
8.4, upgrade to MySQL 8.0
first before upgrading to MySQL 8.4. For
additional details, see
<a class="xref" href="upgrading-from-previous-series.html" title="3.5 Changes in MySQL 8.4">
Section 3.5, “Changes in MySQL 8.4”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For important information about upgrading from MySQL
5.7 to 8.0,
see
<a class="ulink" href="/doc/refman/8.0/en/upgrading-from-previous-series.html" target="_top">
Upgrading
from MySQL 5.7 to
8.0
</a>
.
</p>
</li>
<li class="listitem">
<p>
For important information about upgrading from MySQL
8.0 to 8.4, see
<a class="ulink" href="/doc/refman/8.4/en/upgrading-from-previous-series.html" target="_top">
Upgrading
from MySQL 8.0 to
8.4
</a>
.
</p>
</li>
<li class="listitem">
<p>
In-place downgrading of MySQL is not supported by the
MySQL Yum repository. Follow the instructions in
<a class="xref" href="downgrading.html" title="Chapter 4 Downgrading MySQL">
Chapter 4,
<i>
Downgrading MySQL
</i>
</a>
.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<h3>
<a name="idm46045325959712">
</a>
Upgrading MySQL
</h3>
<p>
Upgrade MySQL components using standard yum (or dnf) commands,
such as MySQL Server:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa9298411"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo yum update mysql-server</code></pre>
</div>
<p>
For platforms that are dnf-enabled:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa37572123"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo dnf upgrade mysql-server</code></pre>
</div>
<p>
Alternatively, you can update MySQL by telling Yum to update
everything on your system, which might take considerably more
time. For platforms that are not dnf-enabled:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa80406770"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo yum update</code></pre>
</div>
<p>
For platforms that are dnf-enabled:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa30615317"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo dnf upgrade</code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The MySQL server always restarts after an update by Yum.
</p>
</div>
</li>
</ol>
</div>
<p>
You can also update only a specific component. Use the following
command to list all the installed packages for the MySQL
components (for dnf-enabled systems, replace
<span class="command">
<strong>
yum
</strong>
</span>
in the command with
<span class="command">
<strong>
dnf
</strong>
</span>
):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa83627872"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo yum list installed | grep <span class="token atrule">"^mysql"</span></code></pre>
</div>
<p>
After identifying the package name of the component of your
choice, update the package with the following command, replacing
<em class="replaceable">
<code>
package-name
</code>
</em>
with the name of the
package. For platforms that are not dnf-enabled:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa46294033"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo yum update <em class="replaceable">package-name</em></code></pre>
</div>
<p>
For dnf-enabled platforms:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa68697740"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">sudo dnf upgrade <em class="replaceable">package-name</em></code></pre>
</div>
<h3>
<a name="updating-yum-repo-client-lib">
</a>
Upgrading the Shared Client Libraries
</h3>
<p>
After updating MySQL using the Yum repository, applications
compiled with older versions of the shared client libraries should
continue to work.
</p>
<p>
<span class="emphasis">
<em>
If you recompile applications and dynamically link them
with the updated libraries:
</em>
</span>
As typical with new
versions of shared libraries where there are differences or
additions in symbol versioning between the newer and older
libraries (for example, between the newer, standard
8.4 shared client libraries and some
older—prior or variant—versions of the shared
libraries shipped natively by the Linux distributions' software
repositories, or from some other sources), any applications
compiled using the updated, newer shared libraries require those
updated libraries on systems where the applications are deployed.
As expected, if those libraries are not in place, the applications
requiring the shared libraries fail. For this reason, be sure to
deploy the packages for the shared libraries from MySQL on those
systems. To do this, add the MySQL Yum repository to the systems
(see
<a class="xref" href="linux-installation-yum-repo.html#yum-repo-setup" title="Adding the MySQL Yum Repository">
Adding the MySQL Yum Repository
</a>
) and install the latest
shared libraries using the instructions given in
<a class="xref" href="linux-installation-yum-repo.html#yum-install-components" title="Installing Additional MySQL Products and Components with Yum">
Installing Additional MySQL Products and Components with Yum
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/json-creation-functions.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="json-creation-functions">
</a>
14.17.2 Functions That Create JSON Values
</h3>
</div>
</div>
</div>
<p>
The functions listed in this section compose JSON values from
component elements.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<a name="function_json-array">
</a>
<p>
<a class="link" href="json-creation-functions.html#function_json-array">
<code class="literal">
JSON_ARRAY([
<em class="replaceable">
<code>
val
</code>
</em>
[,
<em class="replaceable">
<code>
val
</code>
</em>
] ...])
</code>
</a>
</p>
<a class="indexterm" name="idm46045195670816">
</a>
<p>
Evaluates a (possibly empty) list of values and returns a JSON
array containing those values.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa399483"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">JSON_ARRAY</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token string">"abc"</span><span class="token punctuation">,</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token boolean">TRUE</span><span class="token punctuation">,</span> <span class="token function">CURTIME</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME()) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> [1, "abc", null, true, "11:30:24.000000"] <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<a name="function_json-object">
</a>
<p>
<a class="link" href="json-creation-functions.html#function_json-object">
<code class="literal">
JSON_OBJECT([
<em class="replaceable">
<code>
key
</code>
</em>
,
<em class="replaceable">
<code>
val
</code>
</em>
[,
<em class="replaceable">
<code>
key
</code>
</em>
,
<em class="replaceable">
<code>
val
</code>
</em>
] ...])
</code>
</a>
</p>
<a class="indexterm" name="idm46045195658576">
</a>
<p>
Evaluates a (possibly empty) list of key-value pairs and
returns a JSON object containing those pairs. An error occurs
if any key name is
<code class="literal">
NULL
</code>
or the number of
arguments is odd.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa90374869"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">JSON_OBJECT</span><span class="token punctuation">(</span><span class="token string">'id'</span><span class="token punctuation">,</span> <span class="token number">87</span><span class="token punctuation">,</span> <span class="token string">'name'</span><span class="token punctuation">,</span> <span class="token string">'carrot'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> JSON_OBJECT('id', 87, 'name', 'carrot') <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> {"id": 87, "name": "carrot"} <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
<li class="listitem">
<a name="function_json-quote">
</a>
<p>
<a class="link" href="json-creation-functions.html#function_json-quote">
<code class="literal">
JSON_QUOTE(
<em class="replaceable">
<code>
string
</code>
</em>
)
</code>
</a>
</p>
<a class="indexterm" name="idm46045195646864">
</a>
<p>
Quotes a string as a JSON value by wrapping it with double
quote characters and escaping interior quote and other
characters, then returning the result as a
<code class="literal">
utf8mb4
</code>
string. Returns
<code class="literal">
NULL
</code>
if the argument is
<code class="literal">
NULL
</code>
.
</p>
<p>
This function is typically used to produce a valid JSON string
literal for inclusion within a JSON document.
</p>
<p>
Certain special characters are escaped with backslashes per
the escape sequences shown in
<a class="xref" href="json-modification-functions.html#json-unquote-character-escape-sequences" title="Table 14.23 JSON_UNQUOTE() Special Character Escape Sequences">
Table 14.23, “JSON_UNQUOTE() Special Character Escape Sequences”
</a>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa85667661"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">JSON_QUOTE</span><span class="token punctuation">(</span><span class="token string">'null'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token function">JSON_QUOTE</span><span class="token punctuation">(</span><span class="token string">'"null"'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> JSON_QUOTE('null') <span class="token punctuation">|</span> JSON_QUOTE('"null"') <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> "null" <span class="token punctuation">|</span> "\"null\"" <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">JSON_QUOTE</span><span class="token punctuation">(</span><span class="token string">'[1, 2, 3]'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> JSON_QUOTE('[1, 2, 3]') <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> "[1, 2, 3]" <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</li>
</ul>
</div>
<p>
You can also obtain JSON values by casting values of other types
to the
<code class="literal">
JSON
</code>
type using
<a class="link" href="cast-functions.html#function_cast">
<code class="literal">
CAST(
<em class="replaceable">
<code>
value
</code>
</em>
AS
JSON)
</code>
</a>
; see
<a class="xref" href="json.html#json-converting-between-types" title="Converting between JSON and non-JSON values">
Converting between JSON and non-JSON values
</a>
, for more
information.
</p>
<p>
Two aggregate functions generating JSON values are available.
<a class="link" href="aggregate-functions.html#function_json-arrayagg">
<code class="literal">
JSON_ARRAYAGG()
</code>
</a>
returns a result
set as a single JSON array, and
<a class="link" href="aggregate-functions.html#function_json-objectagg">
<code class="literal">
JSON_OBJECTAGG()
</code>
</a>
returns a result
set as a single JSON object. For more information, see
<a class="xref" href="aggregate-functions-and-modifiers.html" title="14.19 Aggregate Functions">
Section 14.19, “Aggregate Functions”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/compressed-format.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="compressed-format">
</a>
18.2.3.3 Compressed Table Characteristics
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045148046496">
</a>
<a class="indexterm" name="idm46045148045040">
</a>
<a class="indexterm" name="idm46045148043968">
</a>
<a class="indexterm" name="idm46045148042480">
</a>
<p>
Compressed storage format is a read-only format that is
generated with the
<a class="link" href="myisampack.html" title="6.6.6 myisampack — Generate Compressed, Read-Only MyISAM Tables">
<span class="command">
<strong>
myisampack
</strong>
</span>
</a>
tool.
Compressed tables can be uncompressed with
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
.
</p>
<p>
Compressed tables have the following characteristics:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Compressed tables take very little disk space. This
minimizes disk usage, which is helpful when using slow disks
(such as CD-ROMs).
</p>
</li>
<li class="listitem">
<p>
Each row is compressed separately, so there is very little
access overhead. The header for a row takes up one to three
bytes depending on the biggest row in the table. Each column
is compressed differently. There is usually a different
Huffman tree for each column. Some of the compression types
are:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
Suffix space compression.
</p>
</li>
<li class="listitem">
<p>
Prefix space compression.
</p>
</li>
<li class="listitem">
<p>
Numbers with a value of zero are stored using one bit.
</p>
</li>
<li class="listitem">
<p>
If values in an integer column have a small range, the
column is stored using the smallest possible type. For
example, a
<a class="link" href="integer-types.html" title="13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT">
<code class="literal">
BIGINT
</code>
</a>
column
(eight bytes) can be stored as a
<a class="link" href="integer-types.html" title="13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT">
<code class="literal">
TINYINT
</code>
</a>
column (one byte)
if all its values are in the range from
<code class="literal">
-128
</code>
to
<code class="literal">
127
</code>
.
</p>
</li>
<li class="listitem">
<p>
If a column has only a small set of possible values, the
data type is converted to
<a class="link" href="enum.html" title="13.3.5 The ENUM Type">
<code class="literal">
ENUM
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
A column may use any combination of the preceding
compression types.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
Can be used for fixed-length or dynamic-length rows.
</p>
</li>
</ul>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
While a compressed table is read only, and you cannot
therefore update or add rows in the table, DDL (Data
Definition Language) operations are still valid. For example,
you may still use
<code class="literal">
DROP
</code>
to drop the table,
and
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
to empty the
table.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/faqs-connectors-apis.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="faqs-connectors-apis">
</a>
A.12 MySQL 8.4 FAQ: Connectors & APIs
</h2>
</div>
</div>
</div>
<a class="indexterm" name="idm46045055086560">
</a>
<p>
For common questions, issues, and answers relating to the MySQL
Connectors and other APIs, see the following areas of the Manual:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="ulink" href="/doc/c-api/8.4/en/c-api-features.html" target="_top">
Using C API Features
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="/doc/connector-odbc/en/connector-odbc-usagenotes.html" target="_top">
Connector/ODBC Notes and Tips
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="/doc/connector-net/en/connector-net-programming.html" target="_top">
Connector/NET Programming
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="ulink" href="/doc/connector-j/en/" target="_top">
MySQL Connector/J Developer Guide
</a>
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-events-statements-history-long-table.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="performance-schema-events-statements-history-long-table">
</a>
29.12.6.3 The events_statements_history_long Table
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045072650304">
</a>
<a class="indexterm" name="idm46045072648848">
</a>
<p>
The
<a class="link" href="performance-schema-events-statements-history-long-table.html" title="29.12.6.3 The events_statements_history_long Table">
<code class="literal">
events_statements_history_long
</code>
</a>
table contains the
<em class="replaceable">
<code>
N
</code>
</em>
most recent
statement events that have ended globally, across all threads.
Statement events are not added to the table until they have
ended. When the table becomes full, the oldest row is
discarded when a new row is added, regardless of which thread
generated either row.
</p>
<p>
The value of
<em class="replaceable">
<code>
N
</code>
</em>
is autosized at
server startup. To set the table size explicitly, set the
<a class="link" href="performance-schema-system-variables.html#sysvar_performance_schema_events_statements_history_long_size">
<code class="literal">
performance_schema_events_statements_history_long_size
</code>
</a>
system variable at server startup.
</p>
<p>
The
<a class="link" href="performance-schema-events-statements-history-long-table.html" title="29.12.6.3 The events_statements_history_long Table">
<code class="literal">
events_statements_history_long
</code>
</a>
table has the same columns as
<a class="link" href="performance-schema-events-statements-current-table.html" title="29.12.6.1 The events_statements_current Table">
<code class="literal">
events_statements_current
</code>
</a>
. See
<a class="xref" href="performance-schema-events-statements-current-table.html" title="29.12.6.1 The events_statements_current Table">
Section 29.12.6.1, “The events_statements_current Table”
</a>
.
Unlike
<a class="link" href="performance-schema-events-statements-current-table.html" title="29.12.6.1 The events_statements_current Table">
<code class="literal">
events_statements_current
</code>
</a>
,
<a class="link" href="performance-schema-events-statements-history-long-table.html" title="29.12.6.3 The events_statements_history_long Table">
<code class="literal">
events_statements_history_long
</code>
</a>
has no indexing.
</p>
<p>
<a class="link" href="truncate-table.html" title="15.1.37 TRUNCATE TABLE Statement">
<code class="literal">
TRUNCATE TABLE
</code>
</a>
is permitted for
the
<a class="link" href="performance-schema-events-statements-history-long-table.html" title="29.12.6.3 The events_statements_history_long Table">
<code class="literal">
events_statements_history_long
</code>
</a>
table. It removes the rows.
</p>
<p>
For more information about the relationship between the three
<code class="literal">
events_statements_
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
event tables, see
<a class="xref" href="performance-schema-event-tables.html" title="29.9 Performance Schema Tables for Current and Historical Events">
Section 29.9, “Performance Schema Tables for Current and Historical Events”
</a>
.
</p>
<p>
For information about configuring whether to collect statement
events, see
<a class="xref" href="performance-schema-statement-tables.html" title="29.12.6 Performance Schema Statement Event Tables">
Section 29.12.6, “Performance Schema Statement Event Tables”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/myisamchk-table-info.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="myisamchk-table-info">
</a>
6.6.4.5 Obtaining Table Information with myisamchk
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045306792704">
</a>
<a class="indexterm" name="idm46045306791248">
</a>
<a class="indexterm" name="idm46045306789760">
</a>
<a class="indexterm" name="idm46045306788272">
</a>
<p>
To obtain a description of a
<code class="literal">
MyISAM
</code>
table or
statistics about it, use the commands shown here. The output
from these commands is explained later in this section.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -d
<em class="replaceable">
<code>
tbl_name
</code>
</em>
</strong>
</span>
</a>
</p>
<p>
Runs
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
in
<span class="quote">
“
<span class="quote">
describe
mode
</span>
”
</span>
to produce a description of your table. If you
start the MySQL server with external locking disabled,
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
may report an error for a table
that is updated while it runs. However, because
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
does not change the table in
describe mode, there is no risk of destroying data.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -dv
<em class="replaceable">
<code>
tbl_name
</code>
</em>
</strong>
</span>
</a>
</p>
<p>
Adding
<code class="option">
-v
</code>
runs
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
in verbose mode so that it produces more information about
the table. Adding
<code class="option">
-v
</code>
a second time produces
even more information.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -eis
<em class="replaceable">
<code>
tbl_name
</code>
</em>
</strong>
</span>
</a>
</p>
<p>
Shows only the most important information from a table. This
operation is slow because it must read the entire table.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -eiv
<em class="replaceable">
<code>
tbl_name
</code>
</em>
</strong>
</span>
</a>
</p>
<p>
This is like
<code class="option">
-eis
</code>
, but tells you what is
being done.
</p>
</li>
</ul>
</div>
<p>
The
<em class="replaceable">
<code>
tbl_name
</code>
</em>
argument can be either
the name of a
<code class="literal">
MyISAM
</code>
table or the name of its
index file, as described in
<a class="xref" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
Section 6.6.4, “myisamchk — MyISAM Table-Maintenance Utility”
</a>
.
Multiple
<em class="replaceable">
<code>
tbl_name
</code>
</em>
arguments can be
given.
</p>
<p>
Suppose that a table named
<code class="literal">
person
</code>
has the
following structure. (The
<code class="literal">
MAX_ROWS
</code>
table
option is included so that in the example output from
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
shown later, some values are
smaller and fit the output format more easily.)
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa85707746"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> person
<span class="token punctuation">(</span>
id <span class="token datatype">INT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span> <span class="token keyword">AUTO_INCREMENT</span><span class="token punctuation">,</span>
last_name <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
first_name <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">20</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
birth <span class="token datatype">DATE</span><span class="token punctuation">,</span>
death <span class="token datatype">DATE</span><span class="token punctuation">,</span>
<span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>id<span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">INDEX</span> <span class="token punctuation">(</span>last_name<span class="token punctuation">,</span> first_name<span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token keyword">INDEX</span> <span class="token punctuation">(</span>birth<span class="token punctuation">)</span>
<span class="token punctuation">)</span> <span class="token keyword">MAX_ROWS</span> <span class="token operator">=</span> <span class="token number">1000000</span> <span class="token keyword">ENGINE</span><span class="token operator">=</span>MYISAM<span class="token punctuation">;</span></code></pre>
</div>
<p>
Suppose also that the table has these data and index file sizes:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-terminal"><div class="docs-select-all right" id="sa26195996"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token property">-rw-rw----</span> 1 mysql mysql 9347072 Aug 19 11<span class="token punctuation">:</span>47 person<span class="token punctuation">.</span>MYD
<span class="token property">-rw-rw----</span> 1 mysql mysql 6066176 Aug 19 11<span class="token punctuation">:</span>47 person<span class="token punctuation">.</span>MYI</code></pre>
</div>
<p>
Example of
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -dvv
</strong>
</span>
</a>
output:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa99661820"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">MyISAM file: person
Record format: Packed
Character set: utf8mb4_0900_ai_ci (255)
File-version: 1
Creation time: 2017-03-30 21:21:30
Status: checked,analyzed,optimized keys,sorted index pages
Auto increment key: 1 Last value: 306688
Data records: 306688 Deleted blocks: 0
Datafile parts: 306688 Deleted data: 0
Datafile pointer (bytes): 4 Keyfile pointer (bytes): 3
Datafile length: 9347072 Keyfile length: 6066176
Max datafile length: 4294967294 Max keyfile length: 17179868159
Recordlength: 54
table description:
Key Start Len Index Type Rec/key Root Blocksize
1 2 4 unique long 1 1024
2 6 80 multip. varchar prefix 0 1024
87 80 varchar 0
3 168 3 multip. uint24 NULL 0 1024
Field Start Length Nullpos Nullbit Type
1 1 1
2 2 4 no zeros
3 6 81 varchar
4 87 81 varchar
5 168 3 1 1 no zeros
6 171 3 1 2 no zeros</code></pre>
</div>
<p>
Explanations for the types of information
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
produces are given here.
<span class="quote">
“
<span class="quote">
Keyfile
</span>
”
</span>
refers to the index file.
<span class="quote">
“
<span class="quote">
Record
</span>
”
</span>
and
<span class="quote">
“
<span class="quote">
row
</span>
”
</span>
are synonymous, as
are
<span class="quote">
“
<span class="quote">
field
</span>
”
</span>
and
<span class="quote">
“
<span class="quote">
column.
</span>
”
</span>
</p>
<p>
The initial part of the table description contains these values:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
MyISAM file
</code>
</p>
<p>
Name of the
<code class="literal">
MyISAM
</code>
(index) file.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Record format
</code>
</p>
<p>
The format used to store table rows. The preceding examples
use
<code class="literal">
Fixed length
</code>
. Other possible values
are
<code class="literal">
Compressed
</code>
and
<code class="literal">
Packed
</code>
. (
<code class="literal">
Packed
</code>
corresponds to what
<code class="literal">
SHOW TABLE STATUS
</code>
reports as
<code class="literal">
Dynamic
</code>
.)
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Chararacter set
</code>
</p>
<p>
The table default character set.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
File-version
</code>
</p>
<p>
Version of
<code class="literal">
MyISAM
</code>
format. Always 1.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Creation time
</code>
</p>
<p>
When the data file was created.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Recover time
</code>
</p>
<p>
When the index/data file was last reconstructed.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Status
</code>
</p>
<p>
Table status flags. Possible values are
<code class="literal">
crashed
</code>
,
<code class="literal">
open
</code>
,
<code class="literal">
changed
</code>
,
<code class="literal">
analyzed
</code>
,
<code class="literal">
optimized keys
</code>
, and
<code class="literal">
sorted index
pages
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Auto increment key
</code>
,
<code class="literal">
Last
value
</code>
</p>
<p>
The key number associated the table's
<code class="literal">
AUTO_INCREMENT
</code>
column, and the most
recently generated value for this column. These fields do
not appear if there is no such column.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Data records
</code>
</p>
<p>
The number of rows in the table.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Deleted blocks
</code>
</p>
<p>
How many deleted blocks still have reserved space. You can
optimize your table to minimize this space. See
<a class="xref" href="myisam-optimization.html" title="9.6.4 MyISAM Table Optimization">
Section 9.6.4, “MyISAM Table Optimization”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Datafile parts
</code>
</p>
<p>
For dynamic-row format, this indicates how many data blocks
there are. For an optimized table without fragmented rows,
this is the same as
<code class="literal">
Data records
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Deleted data
</code>
</p>
<p>
How many bytes of unreclaimed deleted data there are. You
can optimize your table to minimize this space. See
<a class="xref" href="myisam-optimization.html" title="9.6.4 MyISAM Table Optimization">
Section 9.6.4, “MyISAM Table Optimization”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Datafile pointer
</code>
</p>
<p>
The size of the data file pointer, in bytes. It is usually
2, 3, 4, or 5 bytes. Most tables manage with 2 bytes, but
this cannot be controlled from MySQL yet. For fixed tables,
this is a row address. For dynamic tables, this is a byte
address.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Keyfile pointer
</code>
</p>
<p>
The size of the index file pointer, in bytes. It is usually
1, 2, or 3 bytes. Most tables manage with 2 bytes, but this
is calculated automatically by MySQL. It is always a block
address.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Max datafile length
</code>
</p>
<p>
How long the table data file can become, in bytes.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Max keyfile length
</code>
</p>
<p>
How long the table index file can become, in bytes.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Recordlength
</code>
</p>
<p>
How much space each row takes, in bytes.
</p>
</li>
</ul>
</div>
<p>
The
<code class="literal">
table description
</code>
part of the output
includes a list of all keys in the table. For each key,
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
displays some low-level
information:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Key
</code>
</p>
<p>
This key's number. This value is shown only for the first
column of the key. If this value is missing, the line
corresponds to the second or later column of a
multiple-column key. For the table shown in the example,
there are two
<code class="literal">
table description
</code>
lines for
the second index. This indicates that it is a multiple-part
index with two parts.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Start
</code>
</p>
<p>
Where in the row this portion of the index starts.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Len
</code>
</p>
<p>
How long this portion of the index is. For packed numbers,
this should always be the full length of the column. For
strings, it may be shorter than the full length of the
indexed column, because you can index a prefix of a string
column. The total length of a multiple-part key is the sum
of the
<code class="literal">
Len
</code>
values for all key parts.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Index
</code>
</p>
<p>
Whether a key value can exist multiple times in the index.
Possible values are
<code class="literal">
unique
</code>
or
<code class="literal">
multip.
</code>
(multiple).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Type
</code>
</p>
<p>
What data type this portion of the index has. This is a
<code class="literal">
MyISAM
</code>
data type with the possible values
<code class="literal">
packed
</code>
,
<code class="literal">
stripped
</code>
, or
<code class="literal">
empty
</code>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Root
</code>
</p>
<p>
Address of the root index block.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Blocksize
</code>
</p>
<p>
The size of each index block. By default this is 1024, but
the value may be changed at compile time when MySQL is built
from source.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Rec/key
</code>
</p>
<p>
This is a statistical value used by the optimizer. It tells
how many rows there are per value for this index. A unique
index always has a value of 1. This may be updated after a
table is loaded (or greatly changed) with
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
-a
</strong>
</span>
</a>
. If this is not updated at all, a default value
of 30 is given.
</p>
</li>
</ul>
</div>
<p>
The last part of the output provides information about each
column:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Field
</code>
</p>
<p>
The column number.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Start
</code>
</p>
<p>
The byte position of the column within table rows.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Length
</code>
</p>
<p>
The length of the column in bytes.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Nullpos
</code>
,
<code class="literal">
Nullbit
</code>
</p>
<p>
For columns that can be
<code class="literal">
NULL
</code>
,
<code class="literal">
MyISAM
</code>
stores
<code class="literal">
NULL
</code>
values as a flag in a byte. Depending on how many nullable
columns there are, there can be one or more bytes used for
this purpose. The
<code class="literal">
Nullpos
</code>
and
<code class="literal">
Nullbit
</code>
values, if nonempty, indicate
which byte and bit contains that flag indicating whether the
column is
<code class="literal">
NULL
</code>
.
</p>
<p>
The position and number of bytes used to store
<code class="literal">
NULL
</code>
flags is shown in the line for field
1. This is why there are six
<code class="literal">
Field
</code>
lines
for the
<code class="literal">
person
</code>
table even though it has
only five columns.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Type
</code>
</p>
<p>
The data type. The value may contain any of the following
descriptors:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
<code class="literal">
constant
</code>
</p>
<p>
All rows have the same value.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
no endspace
</code>
</p>
<p>
Do not store endspace.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
no endspace, not_always
</code>
</p>
<p>
Do not store endspace and do not do endspace compression
for all values.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
no endspace, no empty
</code>
</p>
<p>
Do not store endspace. Do not store empty values.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
table-lookup
</code>
</p>
<p>
The column was converted to an
<a class="link" href="enum.html" title="13.3.5 The ENUM Type">
<code class="literal">
ENUM
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
zerofill(
<em class="replaceable">
<code>
N
</code>
</em>
)
</code>
</p>
<p>
The most significant
<em class="replaceable">
<code>
N
</code>
</em>
bytes
in the value are always 0 and are not stored.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
no zeros
</code>
</p>
<p>
Do not store zeros.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
always zero
</code>
</p>
<p>
Zero values are stored using one bit.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
<code class="literal">
Huff tree
</code>
</p>
<p>
The number of the Huffman tree associated with the column.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Bits
</code>
</p>
<p>
The number of bits used in the Huffman tree.
</p>
</li>
</ul>
</div>
<p>
The
<code class="literal">
Huff tree
</code>
and
<code class="literal">
Bits
</code>
fields are displayed if the table has been compressed with
<a class="link" href="myisampack.html" title="6.6.6 myisampack — Generate Compressed, Read-Only MyISAM Tables">
<span class="command">
<strong>
myisampack
</strong>
</span>
</a>
. See
<a class="xref" href="myisampack.html" title="6.6.6 myisampack — Generate Compressed, Read-Only MyISAM Tables">
Section 6.6.6, “myisampack — Generate Compressed, Read-Only MyISAM Tables”
</a>
,
for an example of this information.
</p>
<p>
Example of
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -eiv
</strong>
</span>
</a>
output:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa98917762"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">Checking MyISAM file: person
Data records: 306688 Deleted blocks: 0
- check file-size
- check record delete-chain
No recordlinks
- check key delete-chain
block_size 1024:
- check index reference
- check data record references index: 1
Key: 1: Keyblocks used: 98% Packed: 0% Max levels: 3
- check data record references index: 2
Key: 2: Keyblocks used: 99% Packed: 97% Max levels: 3
- check data record references index: 3
Key: 3: Keyblocks used: 98% Packed: -14% Max levels: 3
Total: Keyblocks used: 98% Packed: 89%
- check records and index references
<em class="replaceable">*** LOTS OF ROW NUMBERS DELETED ***</em>
Records: 306688 M.recordlength: 25 Packed: 83%
Recordspace used: 97% Empty space: 2% Blocks/Record: 1.00
Record blocks: 306688 Delete blocks: 0
Record data: 7934464 Deleted data: 0
Lost space: 256512 Linkdata: 1156096
User time 43.08, System time 1.68
Maximum resident set size 0, Integral resident set size 0
Non-physical pagefaults 0, Physical pagefaults 0, Swaps 0
Blocks in 0 out 7, Messages in 0 out 0, Signals 0
Voluntary context switches 0, Involuntary context switches 0
Maximum memory usage: 1046926 bytes (1023k)</code></pre>
</div>
<p>
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk -eiv
</strong>
</span>
</a>
output includes the following
information:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Data records
</code>
</p>
<p>
The number of rows in the table.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Deleted blocks
</code>
</p>
<p>
How many deleted blocks still have reserved space. You can
optimize your table to minimize this space. See
<a class="xref" href="myisam-optimization.html" title="9.6.4 MyISAM Table Optimization">
Section 9.6.4, “MyISAM Table Optimization”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Key
</code>
</p>
<p>
The key number.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Keyblocks used
</code>
</p>
<p>
What percentage of the keyblocks are used. When a table has
just been reorganized with
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
, the
values are very high (very near theoretical maximum).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Packed
</code>
</p>
<p>
MySQL tries to pack key values that have a common suffix.
This can only be used for indexes on
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
CHAR
</code>
</a>
and
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
VARCHAR
</code>
</a>
columns. For long
indexed strings that have similar leftmost parts, this can
significantly reduce the space used. In the preceding
example, the second key is 40 bytes long and a 97% reduction
in space is achieved.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Max levels
</code>
</p>
<p>
How deep the B-tree for this key is. Large tables with long
key values get high values.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Records
</code>
</p>
<p>
How many rows are in the table.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
M.recordlength
</code>
</p>
<p>
The average row length. This is the exact row length for
tables with fixed-length rows, because all rows have the
same length.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Packed
</code>
</p>
<p>
MySQL strips spaces from the end of strings. The
<code class="literal">
Packed
</code>
value indicates the percentage of
savings achieved by doing this.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Recordspace used
</code>
</p>
<p>
What percentage of the data file is used.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Empty space
</code>
</p>
<p>
What percentage of the data file is unused.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Blocks/Record
</code>
</p>
<p>
Average number of blocks per row (that is, how many links a
fragmented row is composed of). This is always 1.0 for
fixed-format tables. This value should stay as close to 1.0
as possible. If it gets too large, you can reorganize the
table. See
<a class="xref" href="myisam-optimization.html" title="9.6.4 MyISAM Table Optimization">
Section 9.6.4, “MyISAM Table Optimization”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Recordblocks
</code>
</p>
<p>
How many blocks (links) are used. For fixed-format tables,
this is the same as the number of rows.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Deleteblocks
</code>
</p>
<p>
How many blocks (links) are deleted.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Recorddata
</code>
</p>
<p>
How many bytes in the data file are used.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Deleted data
</code>
</p>
<p>
How many bytes in the data file are deleted (unused).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Lost space
</code>
</p>
<p>
If a row is updated to a shorter length, some space is lost.
This is the sum of all such losses, in bytes.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
Linkdata
</code>
</p>
<p>
When the dynamic table format is used, row fragments are
linked with pointers (4 to 7 bytes each).
<code class="literal">
Linkdata
</code>
is the sum of the amount of
storage used by all such pointers.
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/counting-rows.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="counting-rows">
</a>
5.3.4.8 Counting Rows
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045324990240">
</a>
<a class="indexterm" name="idm46045324988752">
</a>
<a class="indexterm" name="idm46045324987264">
</a>
<p>
Databases are often used to answer the question,
<span class="quote">
“
<span class="quote">
How
often does a certain type of data occur in a table?
</span>
”
</span>
For example, you might want to know how many pets you have, or
how many pets each owner has, or you might want to perform
various kinds of census operations on your animals.
</p>
<p>
Counting the total number of animals you have is the same
question as
<span class="quote">
“
<span class="quote">
How many rows are in the
<code class="literal">
pet
</code>
table?
</span>
”
</span>
because there is one
record per pet.
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT(*)
</code>
</a>
counts
the number of rows, so the query to count your animals looks
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa95172463"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 9 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Earlier, you retrieved the names of the people who owned pets.
You can use
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT()
</code>
</a>
if you want
to find out how many pets each owner has:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa8249812"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">owner</span><span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> <span class="token keyword">owner</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> owner <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Benny <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Diane <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Gwen <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> Harold <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
The preceding query uses
<code class="literal">
GROUP BY
</code>
to group
all records for each
<code class="literal">
owner
</code>
. The use of
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT()
</code>
</a>
in conjunction with
<code class="literal">
GROUP BY
</code>
is useful for characterizing your
data under various groupings. The following examples show
different ways to perform animal census operations.
</p>
<p>
Number of animals per species:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa99151542"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> species<span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> species<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> species <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> bird <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> hamster <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> snake <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Number of animals per sex:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa82133022"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> sex<span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> sex<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> sex <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NULL <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> f <span class="token punctuation">|</span> 4 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> m <span class="token punctuation">|</span> 4 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
(In this output,
<code class="literal">
NULL
</code>
indicates that the
sex is unknown.)
</p>
<p>
Number of animals per combination of species and sex:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa35379249"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> species <span class="token punctuation">|</span> sex <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> bird <span class="token punctuation">|</span> NULL <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> bird <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> hamster <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> snake <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
You need not retrieve an entire table when you use
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT()
</code>
</a>
. For example, the
previous query, when performed just on dogs and cats, looks
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa49804223"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet
<span class="token keyword">WHERE</span> species <span class="token operator">=</span> <span class="token string">'dog'</span> <span class="token operator">OR</span> species <span class="token operator">=</span> <span class="token string">'cat'</span>
<span class="token keyword">GROUP</span> <span class="token keyword">BY</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> species <span class="token punctuation">|</span> sex <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Or, if you wanted the number of animals per sex only for
animals whose sex is known:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa40625171"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet
<span class="token keyword">WHERE</span> sex <span class="token operator">IS</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span>
<span class="token keyword">GROUP</span> <span class="token keyword">BY</span> species<span class="token punctuation">,</span> sex<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> species <span class="token punctuation">|</span> sex <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> bird <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> cat <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> dog <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> hamster <span class="token punctuation">|</span> f <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> snake <span class="token punctuation">|</span> m <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
If you name columns to select in addition to the
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT()
</code>
</a>
value, a
<code class="literal">
GROUP
BY
</code>
clause should be present that names those same
columns. Otherwise, the following occurs:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
If the
<a class="link" href="sql-mode.html#sqlmode_only_full_group_by">
<code class="literal">
ONLY_FULL_GROUP_BY
</code>
</a>
SQL
mode is enabled, an error occurs:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa62573871"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> sql_mode <span class="token operator">=</span> <span class="token string">'ONLY_FULL_GROUP_BY'</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">owner</span><span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet<span class="token punctuation">;</span>
<span class="token output">ERROR 1140 (42000)<span class="token punctuation">:</span> In aggregated query without GROUP BY, expression
#1 of SELECT list contains nonaggregated column 'menagerie.pet.owner';
this is incompatible with sql_mode=only_full_group_by</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
If
<a class="link" href="sql-mode.html#sqlmode_only_full_group_by">
<code class="literal">
ONLY_FULL_GROUP_BY
</code>
</a>
is
not enabled, the query is processed by treating all rows
as a single group, but the value selected for each named
column is nondeterministic. The server is free to select
the value from any row:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa43885765"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> sql_mode <span class="token operator">=</span> <span class="token string">''</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token keyword">owner</span><span class="token punctuation">,</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">FROM</span> pet<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> owner <span class="token punctuation">|</span> COUNT(*) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Harold <span class="token punctuation">|</span> 8 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
See also
<a class="xref" href="group-by-handling.html" title="14.19.3 MySQL Handling of GROUP BY">
Section 14.19.3, “MySQL Handling of GROUP BY”
</a>
. See
<a class="xref" href="aggregate-functions.html" title="14.19.1 Aggregate Function Descriptions">
Section 14.19.1, “Aggregate Function Descriptions”
</a>
for information about
<a class="link" href="aggregate-functions.html#function_count">
<code class="literal">
COUNT(
<em class="replaceable">
<code>
expr
</code>
</em>
)
</code>
</a>
behavior and related optimizations.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-howto-repuser.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-howto-repuser">
</a>
19.1.2.3 Creating a User for Replication
</h4>
</div>
</div>
</div>
<p>
Each replica connects to the source using a MySQL user name and
password, so there must be a user account on the source that the
replica can use to connect. The user name is specified by the
<code class="literal">
SOURCE_USER
</code>
option of the
<a class="link" href="change-replication-source-to.html" title="15.4.2.2 CHANGE REPLICATION SOURCE TO Statement">
<code class="literal">
CHANGE REPLICATION SOURCE TO
</code>
</a>
statement when you set up a replica. Any account can be used for
this operation, providing it has been granted the
<a class="link" href="privileges-provided.html#priv_replication-slave">
<code class="literal">
REPLICATION SLAVE
</code>
</a>
privilege. You
can choose to create a different account for each replica, or
connect to the source using the same account for each replica.
</p>
<p>
Although you do not have to create an account specifically for
replication, you should be aware that the replication user name
and password are stored in plain text in the replica's
connection metadata repository
<code class="literal">
mysql.slave_master_info
</code>
(see
<a class="xref" href="replica-logs-status.html" title="19.2.4.2 Replication Metadata Repositories">
Section 19.2.4.2, “Replication Metadata Repositories”
</a>
). Therefore, you may want
to create a separate account that has privileges only for the
replication process, to minimize the possibility of compromise
to other accounts.
</p>
<p>
To create a new account, use
<a class="link" href="create-user.html" title="15.7.1.3 CREATE USER Statement">
<code class="literal">
CREATE
USER
</code>
</a>
. To grant this account the privileges required
for replication, use the
<a class="link" href="grant.html" title="15.7.1.6 GRANT Statement">
<code class="literal">
GRANT
</code>
</a>
statement. If you create an account solely for the purposes of
replication, that account needs only the
<a class="link" href="privileges-provided.html#priv_replication-slave">
<code class="literal">
REPLICATION SLAVE
</code>
</a>
privilege. For
example, to set up a new user,
<code class="literal">
repl
</code>
, that can
connect for replication from any host within the
<code class="literal">
example.com
</code>
domain, issue these statements on
the source:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa91957652"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token string">'repl'</span>@<span class="token string">'%.example.com'</span> <span class="token keyword">IDENTIFIED</span> <span class="token keyword">BY</span> <span class="token string">'<em class="replaceable">password</em>'</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">GRANT</span> <span class="token keyword">REPLICATION</span> <span class="token keyword">SLAVE</span> <span class="token keyword">ON</span> <span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> <span class="token keyword">TO</span> <span class="token string">'repl'</span>@<span class="token string">'%.example.com'</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
See
<a class="xref" href="account-management-statements.html" title="15.7.1 Account Management Statements">
Section 15.7.1, “Account Management Statements”
</a>
, for more
information on statements for manipulation of user accounts.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
To connect to the source using a user account that
authenticates with the
<code class="literal">
caching_sha2_password
</code>
plugin, you must
either set up a secure connection as described in
<a class="xref" href="replication-encrypted-connections.html" title="19.3.1 Setting Up Replication to Use Encrypted Connections">
Section 19.3.1, “Setting Up Replication to Use Encrypted Connections”
</a>
, or enable
the unencrypted connection to support password exchange using
an RSA key pair. The
<code class="literal">
caching_sha2_password
</code>
authentication plugin is the default for new users (see
<a class="xref" href="caching-sha2-pluggable-authentication.html" title="8.4.1.2 Caching SHA-2 Pluggable Authentication">
Section 8.4.1.2, “Caching SHA-2 Pluggable Authentication”
</a>
). If
the user account that you create or use for replication (as
specified by the
<code class="literal">
SOURCE_USER
</code>
option) uses
this authentication plugin, and you are not using a secure
connection, you must enable RSA key pair-based password
exchange for a successful connection.
</p>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/telemetry-trace-format.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="telemetry-trace-format">
</a>
35.3.2 Trace Format
</h3>
</div>
</div>
</div>
<p>
A span represents an operation within a trace. For more
information, see
<a class="ulink" href="https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span" target="_blank">
OpenTelemetry
Span
</a>
. The following span types are emitted by the
telemetry component:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="telemetry-trace-format.html#telemetry-trace-format-control" title="Control Span">
Control Span
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="telemetry-trace-format.html#telemetry-trace-format-session" title="Session Span">
Session Span
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="telemetry-trace-format.html#telemetry-trace-format-statement" title="Statement Span">
Statement Span
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="telemetry-trace-format-control">
</a>
Control Span
</h4>
</div>
</div>
</div>
<p>
Issued when the telemetry configuration changes, notifying
downstream system of which signal collection has been enabled
or disabled.
</p>
<p>
This span type has the following attributes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Name: Control
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
trace_enabled
</code>
: Boolean.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
metrics_enabled
</code>
: Boolean.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
logs_enabled
</code>
: Boolean
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
details
</code>
:
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="telemetry-trace-format-session">
</a>
Session Span
</h4>
</div>
</div>
</div>
<p>
Issued when a client session ends, recording data relevant to
that session from initial connection to close of session.
</p>
<p>
This span type has the following attributes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Name: Session
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.processlist_id
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.thread_id
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.user
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.host
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.group
</code>
</p>
</li>
</ul>
</div>
<p>
This span also contains dynamic attributes generated with the
format
<code class="literal">
mysql.session_attr.
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
,
where
<code class="literal">
<em class="replaceable">
<code>
xxx
</code>
</em>
</code>
is the
session connect attribute name. See
<a class="link" href="performance-schema-session-connect-attrs-table.html" title="29.12.9.2 The session_connect_attrs Table">
<code class="literal">
session_connect_attrs
</code>
</a>
.
</p>
<p>
For example, after the following session disconnects:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa43661161"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">select</span> <span class="token operator">*</span> <span class="token keyword">from</span> session_connect_attrs<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> PROCESSLIST_ID <span class="token punctuation">|</span> ATTR_NAME <span class="token punctuation">|</span> ATTR_VALUE <span class="token punctuation">|</span> ORDINAL_POSITION <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> _pid <span class="token punctuation">|</span> 14488 <span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> _platform <span class="token punctuation">|</span> x86_64 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> _os <span class="token punctuation">|</span> Linux <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> _client_name <span class="token punctuation">|</span> libmysql <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> os_user <span class="token punctuation">|</span> malff <span class="token punctuation">|</span> 4 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> _client_version <span class="token punctuation">|</span> 8.4.0<span class="token punctuation">-</span>tr <span class="token punctuation">|</span> 5 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 10 <span class="token punctuation">|</span> program_name <span class="token punctuation">|</span> mysql <span class="token punctuation">|</span> 6 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">7 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
The session span emitted is:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-json"><div class="docs-select-all right" id="sa500386"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-json">Span #
Trace ID <span class="token operator">:</span> 4137db42febad2d00a4123286076ba18
Parent ID <span class="token operator">:</span>
ID <span class="token operator">:</span> b7ff26660b9fcb35
Name <span class="token operator">:</span> session
Kind <span class="token operator">:</span> Internal
Start time <span class="token operator">:</span> <span class="token number">2023</span>-<span class="token number">01</span>-<span class="token number">11</span> <span class="token number">10</span><span class="token operator">:</span><span class="token number">58</span><span class="token operator">:</span><span class="token number">24.79557649</span> +<span class="token number">0000</span> UTC
End time <span class="token operator">:</span> <span class="token number">2023</span>-<span class="token number">01</span>-<span class="token number">11</span> <span class="token number">11</span><span class="token operator">:</span><span class="token number">00</span><span class="token operator">:</span><span class="token number">50.46695685</span> +<span class="token number">0000</span> UTC
Status code <span class="token operator">:</span> Unset
Status message <span class="token operator">:</span>
Attributes<span class="token operator">:</span>
-> mysql.processlist_id<span class="token operator">:</span> Int(<span class="token number">10</span><span class="token punctuation">)</span>
-> mysql.thread_id<span class="token operator">:</span> Int(<span class="token number">50</span><span class="token punctuation">)</span>
-> mysql.user<span class="token operator">:</span> Str(root<span class="token punctuation">)</span>
-> mysql.host<span class="token operator">:</span> Str(localhost<span class="token punctuation">)</span>
-> mysql.group<span class="token operator">:</span> Str(USR_default<span class="token punctuation">)</span>
-> mysql.session_attr._pid<span class="token operator">:</span> Str(<span class="token number">14488</span><span class="token punctuation">)</span>
-> mysql.session_attr._platform<span class="token operator">:</span> Str(x86_64<span class="token punctuation">)</span>
-> mysql.session_attr._os<span class="token operator">:</span> Str(Linux<span class="token punctuation">)</span>
-> mysql.session_attr._client_name<span class="token operator">:</span> Str(libmysql<span class="token punctuation">)</span>
-> mysql.session_attr.os_user<span class="token operator">:</span> Str(malff<span class="token punctuation">)</span>
-> mysql.session_attr._client_version<span class="token operator">:</span> Str(<span class="token number">8.4</span>.<span class="token number">0</span>-tr<span class="token punctuation">)</span>
-> mysql.session_attr.program_name<span class="token operator">:</span> Str(mysql<span class="token punctuation">)</span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="telemetry-trace-format-statement">
</a>
Statement Span
</h4>
</div>
</div>
</div>
<p>
Issued when a statement execution ends in the server,
recording all relevant statement information from the start of
the execution to its completion.
</p>
<p>
This span type has the following attributes:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
Name: stmt
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.event_name
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.lock_time
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sql_text
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.digest_text
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.current_schema
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.object_type
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.object_schema
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.object_name
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sql_errno
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sqlstate
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.message_text
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.error_count
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.warning_count
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.rows_affected
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.rows_sent
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.rows_examined
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.created_tmp_disk_tables
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.created_tmp_tables
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.select_full_join
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.select_full_range_join
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.select_range
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.select_range_check
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.select_scan
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sort_merge_passes
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sort_range
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sort_rows
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.sort_scan
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.no_index_used
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.no_good_index_used
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.max_controlled_memory
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.max_total_memory
</code>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
mysql.cpu_time
</code>
</p>
</li>
</ul>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/optimizer-tracing-typical-usage.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="optimizer-tracing-typical-usage">
</a>
10.15.1 Typical Usage
</h3>
</div>
</div>
</div>
<p>
To perform optimizer tracing entails the following steps:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Enable tracing by executing
<a class="link" href="set-variable.html" title="15.7.6.1 SET Syntax for Variable Assignment">
<code class="literal">
SET
</code>
</a>
<a class="link" href="server-system-variables.html#sysvar_optimizer_trace">
<code class="literal">
optimizer_trace="enabled=ON"
</code>
</a>
.
</p>
</li>
<li class="listitem">
<p>
Execute the statement to be traced. See
<a class="xref" href="traceable-statements.html" title="10.15.3 Traceable Statements">
Section 10.15.3, “Traceable Statements”
</a>
, for a listing of
statements which can be traced.
</p>
</li>
<li class="listitem">
<p>
Examine the contents of the
<a class="link" href="information-schema-optimizer-trace-table.html" title="28.3.19 The INFORMATION_SCHEMA OPTIMIZER_TRACE Table">
<code class="literal">
INFORMATION_SCHEMA.OPTIMIZER_TRACE
</code>
</a>
table.
</p>
</li>
<li class="listitem">
<p>
To examine traces for multiple queries, repeat the previous
two steps as needed.
</p>
</li>
<li class="listitem">
<p>
To disable tracing after you have finished, execute
<code class="literal">
SET optimizer_trace="enabled=OFF"
</code>
.
</p>
</li>
</ol>
</div>
<p>
You can trace only statements which are executed within the
current session; you cannot see traces from other sessions.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/show-binary-logs.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="show-binary-logs">
</a>
15.7.7.2 SHOW BINARY LOGS Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045171199552">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa43576715"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token datatype">BINARY</span> <span class="token keyword">LOGS</span></code></pre>
</div>
<p>
Lists the binary log files on the server. This statement is used
as part of the procedure described in
<a class="xref" href="purge-binary-logs.html" title="15.4.1.1 PURGE BINARY LOGS Statement">
Section 15.4.1.1, “PURGE BINARY LOGS Statement”
</a>
, that shows how to determine
which logs can be purged.
<a class="link" href="show-binary-logs.html" title="15.7.7.2 SHOW BINARY LOGS Statement">
<code class="literal">
SHOW BINARY
LOGS
</code>
</a>
requires the
<a class="link" href="privileges-provided.html#priv_replication-client">
<code class="literal">
REPLICATION
CLIENT
</code>
</a>
privilege (or the deprecated
<a class="link" href="privileges-provided.html#priv_super">
<code class="literal">
SUPER
</code>
</a>
privilege).
</p>
<p>
Encrypted binary log files have a 512-byte file header that
stores information required for encryption and decryption of the
file. This is included in the file size displayed by
<a class="link" href="show-binary-logs.html" title="15.7.7.2 SHOW BINARY LOGS Statement">
<code class="literal">
SHOW BINARY LOGS
</code>
</a>
. The
<code class="literal">
Encrypted
</code>
column shows whether or not the
binary log file is encrypted. Binary log encryption is active if
<a class="link" href="replication-options-binary-log.html#sysvar_binlog_encryption">
<code class="literal">
binlog_encryption=ON
</code>
</a>
is set for
the server. Existing binary log files are not encrypted or
decrypted if binary log encryption is activated or deactivated
while the server is running.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81445869"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token datatype">BINARY</span> <span class="token keyword">LOGS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Log_name <span class="token punctuation">|</span> File_size <span class="token punctuation">|</span> Encrypted <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> binlog.000015 <span class="token punctuation">|</span> 724935 <span class="token punctuation">|</span> Yes <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> binlog.000016 <span class="token punctuation">|</span> 733481 <span class="token punctuation">|</span> Yes <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-ps-setup-disable-background-threads.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-ps-setup-disable-background-threads">
</a>
30.4.4.4 The ps_setup_disable_background_threads() Procedure
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045061547488">
</a>
<a class="indexterm" name="idm46045061545968">
</a>
<p>
Disables Performance Schema instrumentation for all background
threads. Produces a result set indicating how many background
threads were disabled. Already disabled threads do not count.
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-setup-disable-background-threads-parameters">
</a>
Parameters
</h5>
</div>
</div>
</div>
<p>
None.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-ps-setup-disable-background-threads-example">
</a>
Example
</h5>
</div>
</div>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa37217721"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CALL</span> sys<span class="token punctuation">.</span>ps_setup_disable_background_threads<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> summary <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Disabled 24 background threads <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/optimizing-myisam.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title">
<a name="optimizing-myisam">
</a>
10.6 Optimizing for MyISAM Tables
</h2>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="optimizing-queries-myisam.html">
10.6.1 Optimizing MyISAM Queries
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="optimizing-myisam-bulk-data-loading.html">
10.6.2 Bulk Data Loading for MyISAM Tables
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="repair-table-optimization.html">
10.6.3 Optimizing REPAIR TABLE Statements
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045225828160">
</a>
<p>
The
<a class="link" href="myisam-storage-engine.html" title="18.2 The MyISAM Storage Engine">
<code class="literal">
MyISAM
</code>
</a>
storage engine performs
best with read-mostly data or with low-concurrency operations,
because table locks limit the ability to perform simultaneous
updates. In MySQL,
<a class="link" href="innodb-storage-engine.html" title="Chapter 17 The InnoDB Storage Engine">
<code class="literal">
InnoDB
</code>
</a>
is the
default storage engine rather than
<code class="literal">
MyISAM
</code>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/data-change-optimization.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="data-change-optimization">
</a>
10.2.5 Optimizing Data Change Statements
</h3>
</div>
</div>
</div>
<div class="toc">
<dl class="toc">
<dt>
<span class="section">
<a href="insert-optimization.html">
10.2.5.1 Optimizing INSERT Statements
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="update-optimization.html">
10.2.5.2 Optimizing UPDATE Statements
</a>
</span>
</dt>
<dt>
<span class="section">
<a href="delete-optimization.html">
10.2.5.3 Optimizing DELETE Statements
</a>
</span>
</dt>
</dl>
</div>
<a class="indexterm" name="idm46045227673616">
</a>
<p>
This section explains how to speed up data change statements:
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, and
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
. Traditional OLTP
applications and modern web applications typically do many small
data change operations, where concurrency is vital. Data
analysis and reporting applications typically run data change
operations that affect many rows at once, where the main
considerations is the I/O to write large amounts of data and
keep indexes up-to-date. For inserting and updating large
volumes of data (known in the industry as ETL, for
<span class="quote">
“
<span class="quote">
extract-transform-load
</span>
”
</span>
), sometimes you use other
SQL statements or external commands, that mimic the effects of
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, and
<a class="link" href="delete.html" title="15.2.2 DELETE Statement">
<code class="literal">
DELETE
</code>
</a>
statements.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-programs-ndb-redo-log-reader.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="mysql-cluster-programs-ndb-redo-log-reader">
</a>
25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045100007408">
</a>
<p>
Reads a redo log file, checking it for errors, printing its
contents in a human-readable format, or both.
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html" title="25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log">
<span class="command">
<strong>
ndb_redo_log_reader
</strong>
</span>
</a>
is intended for use
primarily by NDB Cluster developers and Support personnel in
debugging and diagnosing problems.
</p>
<p>
This utility remains under development, and its syntax and
behavior are subject to change in future NDB Cluster releases.
</p>
<p>
The C++ source files for
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html" title="25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log">
<span class="command">
<strong>
ndb_redo_log_reader
</strong>
</span>
</a>
can be found in the directory
<code class="filename">
/storage/ndb/src/kernel/blocks/dblqh/redoLogReader
</code>
.
</p>
<p>
Options that can be used with
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html" title="25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log">
<span class="command">
<strong>
ndb_redo_log_reader
</strong>
</span>
</a>
are shown in the
following table. Additional descriptions follow the table.
</p>
<p>
</p>
<h4>
<a name="idm46045099998880">
</a>
Usage
</h4>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa82684379"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal">ndb_redo_log_reader <em class="replaceable">file_name</em> <span class="token punctuation">[</span><em class="replaceable">options</em><span class="token punctuation">]</span></code></pre>
</div>
<p>
<em class="replaceable">
<code>
file_name
</code>
</em>
is the name of a cluster
redo log file. redo log files are located in the numbered
directories under the data node's data directory
(
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-datadir">
<code class="literal">
DataDir
</code>
</a>
); the path
under this directory to the redo log files matches the pattern
<code class="filename">
ndb_
<em class="replaceable">
<code>
nodeid
</code>
</em>
_fs/D
<em class="replaceable">
<code>
#
</code>
</em>
/DBLQH/S
<em class="replaceable">
<code>
#
</code>
</em>
.FragLog
</code>
.
<em class="replaceable">
<code>
nodeid
</code>
</em>
is the data node's node
ID. The two instances of
<em class="replaceable">
<code>
#
</code>
</em>
each
represent a number (not necessarily the same number); the number
following
<code class="literal">
D
</code>
is in the range 8-39 inclusive;
the range of the number following
<code class="literal">
S
</code>
varies
according to the value of the
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-nooffragmentlogfiles">
<code class="literal">
NoOfFragmentLogFiles
</code>
</a>
configuration parameter, whose default value is 16; thus, the
default range of the number in the file name is 0-15 inclusive.
For more information, see
<a class="ulink" href="/doc/ndb-internals/en/ndb-internals-ndbd-filesystemdir-files.html" target="_top">
NDB Cluster Data Node File System Directory
</a>
.
</p>
<p>
The name of the file to be read may be followed by one or more
of the options listed here:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a name="option_ndb_redo_log_reader_dump">
</a>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_dump">
<code class="option">
-dump
</code>
</a>
</p>
<a class="indexterm" name="idm46045099984384">
</a>
<a class="indexterm" name="idm46045099982896">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for dump">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-dump
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Print dump info.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_redo_log_reader_file-key">
</a>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_file-key">
<code class="option">
--file-key
</code>
</a>
,
<code class="option">
-K
</code>
</p>
<a class="indexterm" name="idm46045099972736">
</a>
<a class="indexterm" name="idm46045099971248">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for file-key">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--file-key=key
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Supply file decryption key using
<code class="literal">
stdin
</code>
,
<code class="literal">
tty
</code>
, or a
<code class="filename">
my.cnf
</code>
file.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_redo_log_reader_file-key-from-stdin">
</a>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_file-key-from-stdin">
<code class="option">
--file-key-from-stdin
</code>
</a>
</p>
<a class="indexterm" name="idm46045099959280">
</a>
<a class="indexterm" name="idm46045099957776">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for file-key-from-stdin">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--file-key-from-stdin
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Supply file decryption key using
<code class="literal">
stdin
</code>
.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_filedescriptors">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for filedescriptors">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-filedescriptors
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_filedescriptors">
<code class="option">
-filedescriptors
</code>
</a>
:
Print file descriptors only.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_help">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for help">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
--help
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_help">
<code class="option">
--help
</code>
</a>
: Print
usage information.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_redo_log_reader_lap">
</a>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_lap">
<code class="option">
-lap
</code>
</a>
</p>
<a class="indexterm" name="idm46045099931536">
</a>
<a class="indexterm" name="idm46045099930048">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for lap">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-lap
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Provide lap info, with max GCI started and completed.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_mbyte">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for mbyte">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-mbyte #
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Numeric
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
15
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_mbyte">
<code class="option">
-mbyte
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
: Starting megabyte.
</p>
<p>
<em class="replaceable">
<code>
#
</code>
</em>
is an integer in the range 0 to
15, inclusive.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_mbyteheaders">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for mbyteheaders">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-mbyteheaders
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_mbyteheaders">
<code class="option">
-mbyteheaders
</code>
</a>
:
Show only the first page header of every megabyte in the
file.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_noprint">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for noprint">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-noprint
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_noprint">
<code class="option">
-noprint
</code>
</a>
: Do not
print the contents of the log file.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_nocheck">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for nocheck">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-nocheck
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_nocheck">
<code class="option">
-nocheck
</code>
</a>
: Do not
check the log file for errors.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_page">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for page">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-page #
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
0
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
31
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_page">
<code class="option">
-page
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
: Start at this page.
</p>
<p>
<em class="replaceable">
<code>
#
</code>
</em>
is an integer in the range 0 to
31, inclusive.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_pageheaders">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for pageheaders">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-pageheaders
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_pageheaders">
<code class="option">
-pageheaders
</code>
</a>
:
Show page headers only.
</p>
</li>
<li class="listitem">
<a name="option_ndb_redo_log_reader_pageindex">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for pageindex">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-pageindex #
</code>
</td>
</tr>
<tr>
<th>
Type
</th>
<td>
Integer
</td>
</tr>
<tr>
<th>
Default Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
<tr>
<th>
Minimum Value
</th>
<td>
<code class="literal">
12
</code>
</td>
</tr>
<tr>
<th>
Maximum Value
</th>
<td>
<code class="literal">
8191
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_pageindex">
<code class="option">
-pageindex
<em class="replaceable">
<code>
#
</code>
</em>
</code>
</a>
: Start at this page
index.
</p>
<p>
<em class="replaceable">
<code>
#
</code>
</em>
is an integer between 12 and
8191, inclusive.
</p>
</li>
<li class="listitem">
<p>
<a name="option_ndb_redo_log_reader_twiddle">
</a>
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html#option_ndb_redo_log_reader_twiddle">
<code class="option">
-twiddle
</code>
</a>
</p>
<a class="indexterm" name="idm46045099834224">
</a>
<a class="indexterm" name="idm46045099832736">
</a>
<div class="informaltable">
<table frame="box" rules="all" summary="Properties for twiddle">
<colgroup>
<col style="width: 30%"/>
<col style="width: 70%"/>
</colgroup>
<tbody>
<tr>
<th>
Command-Line Format
</th>
<td>
<code class="literal">
-twiddle
</code>
</td>
</tr>
</tbody>
</table>
</div>
<p>
Bit-shifted dump.
</p>
</li>
</ul>
</div>
<p>
Like
<a class="link" href="mysql-cluster-programs-ndb-print-backup-file.html" title="25.5.17 ndb_print_backup_file — Print NDB Backup File Contents">
<span class="command">
<strong>
ndb_print_backup_file
</strong>
</span>
</a>
and
<a class="link" href="mysql-cluster-programs-ndb-print-schema-file.html" title="25.5.20 ndb_print_schema_file — Print NDB Schema File Contents">
<span class="command">
<strong>
ndb_print_schema_file
</strong>
</span>
</a>
(and unlike most of the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
utilities that are intended to
be run on a management server host or to connect to a management
server)
<a class="link" href="mysql-cluster-programs-ndb-redo-log-reader.html" title="25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log">
<span class="command">
<strong>
ndb_redo_log_reader
</strong>
</span>
</a>
must be run on a
cluster data node, since it accesses the data node file system
directly. Because it does not make use of the management server,
this utility can be used when the management server is not
running, and even when the cluster has been completely shut
down.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/myisam-start.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="myisam-start">
</a>
18.2.1 MyISAM Startup Options
</h3>
</div>
</div>
</div>
<p>
The following options to
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
can be used to
change the behavior of
<code class="literal">
MyISAM
</code>
tables. For
additional information, see
<a class="xref" href="server-options.html" title="7.1.7 Server Command Options">
Section 7.1.7, “Server Command Options”
</a>
.
</p>
<div class="table">
<a name="idm46045148327984">
</a>
<p class="title">
<b>
Table 18.3 MyISAM Option and Variable Reference
</b>
</p>
<div class="table-contents">
<table frame="box" rules="all" summary="Reference for MyISAM command-line options and system variables.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
<col style="width: 15%"/>
</colgroup>
<thead>
<tr>
<th scope="col">
Name
</th>
<th scope="col">
Cmd-Line
</th>
<th scope="col">
Option File
</th>
<th scope="col">
System Var
</th>
<th scope="col">
Status Var
</th>
<th scope="col">
Var Scope
</th>
<th scope="col">
Dynamic
</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_bulk_insert_buffer_size">
bulk_insert_buffer_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Both
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_concurrent_insert">
concurrent_insert
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_delay_key_write">
delay_key_write
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_have_rtree_keys">
have_rtree_keys
</a>
</th>
<td>
</td>
<td>
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_key_buffer_size">
key_buffer_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-options.html#option_mysqld_log-isam">
log-isam
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
</td>
<td>
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-options.html#option_mysqld_myisam-block-size">
myisam-block-size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
</td>
<td>
</td>
<td>
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_data_pointer_size">
myisam_data_pointer_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_max_sort_file_size">
myisam_max_sort_file_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_mmap_size">
myisam_mmap_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_recover_options">
myisam_recover_options
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
No
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_sort_buffer_size">
myisam_sort_buffer_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Both
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_stats_method">
myisam_stats_method
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Both
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_myisam_use_mmap">
myisam_use_mmap
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Global
</td>
<td>
Yes
</td>
</tr>
<tr>
<th scope="row">
<a class="link" href="server-system-variables.html#sysvar_tmp_table_size">
tmp_table_size
</a>
</th>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
Yes
</td>
<td>
</td>
<td>
Both
</td>
<td>
Yes
</td>
</tr>
</tbody>
</table>
</div>
<div class="table-contents">
<table cellpadding="0" cellspacing="0" style="position: fixed; top: 0px; display: none; left: 401px; width: 739px;">
<thead>
<tr>
<th scope="col" style="width: 195.406px;">
Name
</th>
<th scope="col" style="width: 92.4375px;">
Cmd-Line
</th>
<th scope="col" style="width: 95.8125px;">
Option File
</th>
<th scope="col" style="width: 96.5px;">
System Var
</th>
<th scope="col" style="width: 94.7812px;">
Status Var
</th>
<th scope="col" style="width: 93.7344px;">
Var Scope
</th>
<th scope="col" style="width: 69.3281px;">
Dynamic
</th>
</tr>
</thead>
</table>
</div>
</div>
<br class="table-break"/>
<p>
The following system variables affect the behavior of
<code class="literal">
MyISAM
</code>
tables. For additional information, see
<a class="xref" href="server-system-variables.html" title="7.1.8 Server System Variables">
Section 7.1.8, “Server System Variables”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_bulk_insert_buffer_size">
<code class="literal">
bulk_insert_buffer_size
</code>
</a>
</p>
<a class="indexterm" name="idm46045148203872">
</a>
<a class="indexterm" name="idm46045148202832">
</a>
<p>
The size of the tree cache used in bulk insert optimization.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
This is a limit
<span class="emphasis">
<em>
per thread
</em>
</span>
!
</p>
</div>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_delay_key_write">
<code class="option">
delay_key_write=ALL
</code>
</a>
</p>
<a class="indexterm" name="idm46045148197904">
</a>
<a class="indexterm" name="idm46045148196816">
</a>
<p>
Don't flush key buffers between writes for any
<code class="literal">
MyISAM
</code>
table.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
If you do this, you should not access
<code class="literal">
MyISAM
</code>
tables from another program (such
as from another MySQL server or with
<a class="link" href="myisamchk.html" title="6.6.4 myisamchk — MyISAM Table-Maintenance Utility">
<span class="command">
<strong>
myisamchk
</strong>
</span>
</a>
) when the tables are in use.
Doing so risks index corruption. Using
<a class="link" href="server-options.html#option_mysqld_external-locking">
<code class="option">
--external-locking
</code>
</a>
does not
eliminate this risk.
</p>
</div>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_myisam_max_sort_file_size">
<code class="literal">
myisam_max_sort_file_size
</code>
</a>
</p>
<a class="indexterm" name="idm46045148188144">
</a>
<a class="indexterm" name="idm46045148187040">
</a>
<p>
The maximum size of the temporary file that MySQL is permitted
to use while re-creating a
<code class="literal">
MyISAM
</code>
index
(during
<a class="link" href="repair-table.html" title="15.7.3.5 REPAIR TABLE Statement">
<code class="literal">
REPAIR TABLE
</code>
</a>
,
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
, or
<a class="link" href="load-data.html" title="15.2.9 LOAD DATA Statement">
<code class="literal">
LOAD DATA
</code>
</a>
). If the file size
would be larger than this value, the index is created using
the key cache instead, which is slower. The value is given in
bytes.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_myisam_recover_options">
<code class="literal">
myisam_recover_options=
<em class="replaceable">
<code>
mode
</code>
</em>
</code>
</a>
</p>
<a class="indexterm" name="idm46045148178080">
</a>
<a class="indexterm" name="idm46045148177040">
</a>
<p>
Set the mode for automatic recovery of crashed
<code class="literal">
MyISAM
</code>
tables.
</p>
</li>
<li class="listitem">
<p>
<a class="link" href="server-system-variables.html#sysvar_myisam_sort_buffer_size">
<code class="literal">
myisam_sort_buffer_size
</code>
</a>
</p>
<a class="indexterm" name="idm46045148172320">
</a>
<a class="indexterm" name="idm46045148171280">
</a>
<p>
Set the size of the buffer used when recovering tables.
</p>
</li>
</ul>
</div>
<p>
Automatic recovery is activated if you start
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
with the
<a class="link" href="server-system-variables.html#sysvar_myisam_recover_options">
<code class="literal">
myisam_recover_options
</code>
</a>
system
variable set. In this case, when the server opens a
<code class="literal">
MyISAM
</code>
table, it checks whether the table is
marked as crashed or whether the open count variable for the table
is not 0 and you are running the server with external locking
disabled. If either of these conditions is true, the following
happens:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
The server checks the table for errors.
</p>
</li>
<li class="listitem">
<p>
If the server finds an error, it tries to do a fast table
repair (with sorting and without re-creating the data file).
</p>
</li>
<li class="listitem">
<p>
If the repair fails because of an error in the data file (for
example, a duplicate-key error), the server tries again, this
time re-creating the data file.
</p>
</li>
<li class="listitem">
<p>
If the repair still fails, the server tries once more with the
old repair option method (write row by row without sorting).
This method should be able to repair any type of error and has
low disk space requirements.
</p>
</li>
</ul>
</div>
<p>
If the recovery wouldn't be able to recover all rows from
previously completed statements and you didn't specify
<code class="literal">
FORCE
</code>
in the value of the
<a class="link" href="server-system-variables.html#sysvar_myisam_recover_options">
<code class="literal">
myisam_recover_options
</code>
</a>
system
variable, automatic repair aborts with an error message in the
error log:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa65220076"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">Error: Couldn't repair table: test.g00pages</code></pre>
</div>
<p>
If you specify
<code class="literal">
FORCE
</code>
, a warning like this is
written instead:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-none"><div class="docs-select-all right" id="sa57058481"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">Warning: Found 344 of 354 rows when repairing ./test/g00pages</code></pre>
</div>
<p>
If the automatic recovery value includes
<code class="literal">
BACKUP
</code>
, the recovery process creates files with
names of the form
<code class="filename">
<em class="replaceable">
<code>
tbl_name-datetime
</code>
</em>
.BAK
</code>
.
You should have a
<span class="command">
<strong>
cron
</strong>
</span>
script that
automatically moves these files from the database directories to
backup media.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-config-example.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysql-cluster-config-example">
</a>
25.4.3.1 NDB Cluster Configuration: Basic Example
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045120743520">
</a>
<a class="indexterm" name="idm46045120742032">
</a>
<a class="indexterm" name="idm46045120740544">
</a>
<p>
To support NDB Cluster, you should update
<code class="filename">
my.cnf
</code>
as shown in the following example.
You may also specify these parameters on the command line when
invoking the executables.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The options shown here should not be confused with those that
are used in
<code class="filename">
config.ini
</code>
global
configuration files. Global configuration options are
discussed later in this section.
</p>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa47666699"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token comment" spellcheck="true"># my.cnf</span>
<span class="token comment" spellcheck="true"># example additions to my.cnf for NDB Cluster</span>
<span class="token comment" spellcheck="true"># (valid in MySQL 8.4)</span>
<span class="token comment" spellcheck="true"># enable ndbcluster storage engine, and provide connection string for</span>
<span class="token comment" spellcheck="true"># management server host (default port is 1186)</span>
<span class="token selector">[mysqld]</span>
<span class="token constant">ndbcluster</span>
<span class="token constant">ndb-connectstring</span><span class="token attr-value"><span class="token punctuation">=</span>ndb_mgmd.mysql.com</span>
<span class="token comment" spellcheck="true"># provide connection string for management server host (default port: 1186)</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">connect-string</span><span class="token attr-value"><span class="token punctuation">=</span>ndb_mgmd.mysql.com</span>
<span class="token comment" spellcheck="true"># provide connection string for management server host (default port: 1186)</span>
<span class="token selector">[ndb_mgm]</span>
<span class="token constant">connect-string</span><span class="token attr-value"><span class="token punctuation">=</span>ndb_mgmd.mysql.com</span>
<span class="token comment" spellcheck="true"># provide location of cluster configuration file</span>
<span class="token comment" spellcheck="true"># IMPORTANT: When starting the management server with this option in the</span>
<span class="token comment" spellcheck="true"># configuration file, the use of --initial or --reload on the command line when</span>
<span class="token comment" spellcheck="true"># invoking ndb_mgmd is also required.</span>
<span class="token selector">[ndb_mgmd]</span>
<span class="token constant">config-file</span><span class="token attr-value"><span class="token punctuation">=</span>/etc/config.ini</span></code></pre>
</div>
<p>
(For more information on connection strings, see
<a class="xref" href="mysql-cluster-connection-strings.html" title="25.4.3.3 NDB Cluster Connection Strings">
Section 25.4.3.3, “NDB Cluster Connection Strings”
</a>
.)
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa368294"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token comment" spellcheck="true"># my.cnf</span>
<span class="token comment" spellcheck="true"># example additions to my.cnf for NDB Cluster</span>
<span class="token comment" spellcheck="true"># (works on all versions)</span>
<span class="token comment" spellcheck="true"># enable ndbcluster storage engine, and provide connection string for management</span>
<span class="token comment" spellcheck="true"># server host to the default port 1186</span>
<span class="token selector">[mysqld]</span>
<span class="token constant">ndbcluster</span>
<span class="token constant">ndb-connectstring</span><span class="token attr-value"><span class="token punctuation">=</span>ndb_mgmd.mysql.com:1186</span></code></pre>
</div>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
Once you have started a
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
process with
the
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDBCLUSTER
</code>
</a>
and
<code class="literal">
ndb-connectstring
</code>
parameters in the
<code class="literal">
[mysqld]
</code>
in the
<code class="filename">
my.cnf
</code>
file as shown previously, you cannot execute any
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
or
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
statements without
having actually started the cluster. Otherwise, these
statements fail with an error.
<span class="emphasis">
<em>
This is by
design
</em>
</span>
.
</p>
</div>
<p>
You may also use a separate
<code class="literal">
[mysql_cluster]
</code>
section in the cluster
<code class="filename">
my.cnf
</code>
file for
settings to be read and used by all executables:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa47590244"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token comment" spellcheck="true"># cluster-specific settings</span>
<span class="token selector">[mysql_cluster]</span>
<span class="token constant">ndb-connectstring</span><span class="token attr-value"><span class="token punctuation">=</span>ndb_mgmd.mysql.com:1186</span></code></pre>
</div>
<p>
For additional
<a class="link" href="mysql-cluster.html" title="Chapter 25 MySQL NDB Cluster 8.4">
<code class="literal">
NDB
</code>
</a>
variables that
can be set in the
<code class="filename">
my.cnf
</code>
file, see
<a class="xref" href="mysql-cluster-options-variables.html#mysql-cluster-system-variables" title="25.4.3.9.2 NDB Cluster System Variables">
Section 25.4.3.9.2, “NDB Cluster System Variables”
</a>
.
</p>
<p>
The NDB Cluster global configuration file is by convention named
<code class="filename">
config.ini
</code>
(but this is not required). If
needed, it is read by
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
at startup and
can be placed in any location that can be read by it. The
location and name of the configuration are specified using
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_config-file">
<code class="option">
--config-file=
<em class="replaceable">
<code>
path_name
</code>
</em>
</code>
</a>
with
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
on the command line. This
option has no default value, and is ignored if
<a class="link" href="mysql-cluster-programs-ndb-mgmd.html" title="25.5.4 ndb_mgmd — The NDB Cluster Management Server Daemon">
<span class="command">
<strong>
ndb_mgmd
</strong>
</span>
</a>
uses the configuration cache.
</p>
<p>
The global configuration file for NDB Cluster uses INI format,
which consists of sections preceded by section headings
(surrounded by square brackets), followed by the appropriate
parameter names and values. One deviation from the standard INI
format is that the parameter name and value can be separated by
a colon (
<code class="literal">
:
</code>
) as well as the equal sign
(
<code class="literal">
=
</code>
); however, the equal sign is preferred.
Another deviation is that sections are not uniquely identified
by section name. Instead, unique sections (such as two different
nodes of the same type) are identified by a unique ID specified
as a parameter within the section.
</p>
<p>
Default values are defined for most parameters, and can also be
specified in
<code class="filename">
config.ini
</code>
. To create a
default value section, simply add the word
<code class="literal">
default
</code>
to the section name. For example, an
<code class="literal">
[ndbd]
</code>
section contains parameters that apply
to a particular data node, whereas an
<code class="literal">
[ndbd
default]
</code>
section contains parameters that apply to all
data nodes. Suppose that all data nodes should use the same data
memory size. To configure them all, create an
<code class="literal">
[ndbd
default]
</code>
section that contains a
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-datamemory">
<code class="literal">
DataMemory
</code>
</a>
line to
specify the data memory size.
</p>
<p>
If used, the
<code class="literal">
[ndbd default]
</code>
section must
precede any
<code class="literal">
[ndbd]
</code>
sections in the
configuration file. This is also true for
<code class="literal">
default
</code>
sections of any other type.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
In some older releases of NDB Cluster, there was no default
value for
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-noofreplicas">
<code class="literal">
NoOfReplicas
</code>
</a>
, which
always had to be specified explicitly in the
<code class="literal">
[ndbd
default]
</code>
section. Although this parameter now has a
default value of 2, which is the recommended setting in most
common usage scenarios, it is still recommended practice to
set this parameter explicitly.
</p>
</div>
<p>
The global configuration file must define the computers and
nodes involved in the cluster and on which computers these nodes
are located. An example of a simple configuration file for a
cluster consisting of one management server, two data nodes and
two MySQL servers is shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa76558969"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token comment" spellcheck="true"># file "config.ini" - 2 data nodes and 2 SQL nodes</span>
<span class="token comment" spellcheck="true"># This file is placed in the startup directory of ndb_mgmd (the</span>
<span class="token comment" spellcheck="true"># management server)</span>
<span class="token comment" spellcheck="true"># The first MySQL Server can be started from any host. The second</span>
<span class="token comment" spellcheck="true"># can be started only on the host mysqld_5.mysql.com</span>
<span class="token selector">[ndbd default]</span>
<span class="token constant">NoOfReplicas</span><span class="token attr-value"><span class="token punctuation">=</span> 2</span>
<span class="token constant">DataDir</span><span class="token attr-value"><span class="token punctuation">=</span> /var/lib/mysql-cluster</span>
<span class="token selector">[ndb_mgmd]</span>
<span class="token constant">Hostname</span><span class="token attr-value"><span class="token punctuation">=</span> ndb_mgmd.mysql.com</span>
<span class="token constant">DataDir</span><span class="token attr-value"><span class="token punctuation">=</span> /var/lib/mysql-cluster</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">HostName</span><span class="token attr-value"><span class="token punctuation">=</span> ndbd_2.mysql.com</span>
<span class="token selector">[ndbd]</span>
<span class="token constant">HostName</span><span class="token attr-value"><span class="token punctuation">=</span> ndbd_3.mysql.com</span>
<span class="token selector">[mysqld]</span>
<span class="token selector">[mysqld]</span>
<span class="token constant">HostName</span><span class="token attr-value"><span class="token punctuation">=</span> mysqld_5.mysql.com</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The preceding example is intended as a minimal starting
configuration for purposes of familiarization with NDB Cluster
, and is almost certain not to be sufficient for production
settings. See
<a class="xref" href="mysql-cluster-config-starting.html" title="25.4.3.2 Recommended Starting Configuration for NDB Cluster">
Section 25.4.3.2, “Recommended Starting Configuration for NDB Cluster”
</a>
,
which provides a more complete example starting configuration.
</p>
</div>
<p>
Each node has its own section in the
<code class="filename">
config.ini
</code>
file. For example, this cluster
has two data nodes, so the preceding configuration file contains
two
<code class="literal">
[ndbd]
</code>
sections defining these nodes.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
Do not place comments on the same line as a section heading in
the
<code class="filename">
config.ini
</code>
file; this causes the
management server not to start because it cannot parse the
configuration file in such cases.
</p>
</div>
<h5>
<a name="mysql-cluster-config-ini-sections">
</a>
Sections of the config.ini File
</h5>
<p>
There are six different sections that you can use in the
<code class="filename">
config.ini
</code>
configuration file, as described
in the following list:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
[computer]
</code>
: Defines cluster hosts. This
is not required to configure a viable NDB Cluster, but be
may used as a convenience when setting up a large cluster.
See
<a class="xref" href="mysql-cluster-computer-definition.html" title="25.4.3.4 Defining Computers in an NDB Cluster">
Section 25.4.3.4, “Defining Computers in an NDB Cluster”
</a>
, for
more information.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[ndbd]
</code>
: Defines a cluster data node
(
<a class="link" href="mysql-cluster-programs-ndbd.html" title="25.5.1 ndbd — The NDB Cluster Data Node Daemon">
<span class="command">
<strong>
ndbd
</strong>
</span>
</a>
process). See
<a class="xref" href="mysql-cluster-ndbd-definition.html" title="25.4.3.6 Defining NDB Cluster Data Nodes">
Section 25.4.3.6, “Defining NDB Cluster Data Nodes”
</a>
, for
details.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[mysqld]
</code>
: Defines the cluster's MySQL
server nodes (also called SQL or API nodes). For a
discussion of SQL node configuration, see
<a class="xref" href="mysql-cluster-api-definition.html" title="25.4.3.7 Defining SQL and Other API Nodes in an NDB Cluster">
Section 25.4.3.7, “Defining SQL and Other API Nodes in an NDB Cluster”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[mgm]
</code>
or
<code class="literal">
[ndb_mgmd]
</code>
:
Defines a cluster management server (MGM) node. For
information concerning the configuration of management
nodes, see
<a class="xref" href="mysql-cluster-mgm-definition.html" title="25.4.3.5 Defining an NDB Cluster Management Server">
Section 25.4.3.5, “Defining an NDB Cluster Management Server”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[tcp]
</code>
: Defines a TCP/IP connection
between cluster nodes, with TCP/IP being the default
transport protocol. Normally,
<code class="literal">
[tcp]
</code>
or
<code class="literal">
[tcp default]
</code>
sections are not required
to set up an NDB Cluster, as the cluster handles this
automatically; however, it may be necessary in some
situations to override the defaults provided by the cluster.
See
<a class="xref" href="mysql-cluster-tcp-definition.html" title="25.4.3.10 NDB Cluster TCP/IP Connections">
Section 25.4.3.10, “NDB Cluster TCP/IP Connections”
</a>
, for
information about available TCP/IP configuration parameters
and how to use them. (You may also find
<a class="xref" href="mysql-cluster-tcp-definition-direct.html" title="25.4.3.11 NDB Cluster TCP/IP Connections Using Direct Connections">
Section 25.4.3.11, “NDB Cluster TCP/IP Connections Using Direct Connections”
</a>
to be
of interest in some cases.)
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[shm]
</code>
: Defines shared-memory connections
between nodes. In MySQL 8.4, it is enabled by
default, but should still be considered experimental. For a
discussion of SHM interconnects, see
<a class="xref" href="mysql-cluster-shm-definition.html" title="25.4.3.12 NDB Cluster Shared-Memory Connections">
Section 25.4.3.12, “NDB Cluster Shared-Memory Connections”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
[sci]
</code>
: Defines Scalable Coherent
Interface connections between cluster data nodes. Not
supported in NDB 8.4.
</p>
</li>
</ul>
</div>
<p>
You can define
<code class="literal">
default
</code>
values for each
section. If used, a
<code class="literal">
default
</code>
section should
come before any other sections of that type. For example, an
<code class="literal">
[ndbd default]
</code>
section should appear in the
configuration file before any
<code class="literal">
[ndbd]
</code>
sections.
</p>
<p>
NDB Cluster parameter names are case-insensitive, unless
specified in MySQL Server
<code class="filename">
my.cnf
</code>
or
<code class="filename">
my.ini
</code>
files.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/example-auto-increment.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="example-auto-increment">
</a>
5.6.9 Using AUTO_INCREMENT
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045324592208">
</a>
<a class="indexterm" name="idm46045324591136">
</a>
<a class="indexterm" name="idm46045324590064">
</a>
<p>
The
<code class="literal">
AUTO_INCREMENT
</code>
attribute can be used to
generate a unique identity for new rows:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa89455029"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> animals <span class="token punctuation">(</span>
id <span class="token datatype">MEDIUMINT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span> <span class="token keyword">AUTO_INCREMENT</span><span class="token punctuation">,</span>
<span class="token keyword">name</span> <span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">30</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
<span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>id<span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span>
<span class="token punctuation">(</span><span class="token string">'dog'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'cat'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'penguin'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token punctuation">(</span><span class="token string">'lax'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'whale'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'ostrich'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> animals<span class="token punctuation">;</span></code></pre>
</div>
<p>
Which returns:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa2699765"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">+----+---------+
| id | name |
+----+---------+
| 1 | dog |
| 2 | cat |
| 3 | penguin |
| 4 | lax |
| 5 | whale |
| 6 | ostrich |
+----+---------+</code></pre>
</div>
<p>
No value was specified for the
<code class="literal">
AUTO_INCREMENT
</code>
column, so MySQL assigned sequence numbers automatically. You
can also explicitly assign 0 to the column to generate sequence
numbers, unless the
<a class="link" href="sql-mode.html#sqlmode_no_auto_value_on_zero">
<code class="literal">
NO_AUTO_VALUE_ON_ZERO
</code>
</a>
SQL mode
is enabled. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa22351037"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span>id<span class="token punctuation">,</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token string">'groundhog'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
If the column is declared
<code class="literal">
NOT NULL
</code>
, it is
also possible to assign
<code class="literal">
NULL
</code>
to the column to
generate sequence numbers. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa76458133"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span>id<span class="token punctuation">,</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span><span class="token string">'squirrel'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
When you insert any other value into an
<code class="literal">
AUTO_INCREMENT
</code>
column, the column is set to
that value and the sequence is reset so that the next
automatically generated value follows sequentially from the
largest column value. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa87424710"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span>id<span class="token punctuation">,</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token number">100</span><span class="token punctuation">,</span><span class="token string">'rabbit'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span>id<span class="token punctuation">,</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span><span class="token string">'mouse'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> animals<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> id <span class="token punctuation">|</span> name <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> dog <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> cat <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 3 <span class="token punctuation">|</span> penguin <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 4 <span class="token punctuation">|</span> lax <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 5 <span class="token punctuation">|</span> whale <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 6 <span class="token punctuation">|</span> ostrich <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 7 <span class="token punctuation">|</span> groundhog <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 8 <span class="token punctuation">|</span> squirrel <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 100 <span class="token punctuation">|</span> rabbit <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 101 <span class="token punctuation">|</span> mouse <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
Updating an existing
<code class="literal">
AUTO_INCREMENT
</code>
column
value also resets the
<code class="literal">
AUTO_INCREMENT
</code>
sequence.
</p>
<p>
You can retrieve the most recent automatically generated
<code class="literal">
AUTO_INCREMENT
</code>
value with the
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
SQL function or
the
<a class="ulink" href="/doc/c-api/8.4/en/mysql-insert-id.html" target="_top">
<code class="literal">
mysql_insert_id()
</code>
</a>
C API
function. These functions are connection-specific, so their
return values are not affected by another connection which is
also performing inserts.
</p>
<p>
Use the smallest integer data type for the
<code class="literal">
AUTO_INCREMENT
</code>
column that is large enough to
hold the maximum sequence value you require. When the column
reaches the upper limit of the data type, the next attempt to
generate a sequence number fails. Use the
<code class="literal">
UNSIGNED
</code>
attribute if possible to allow a
greater range. For example, if you use
<a class="link" href="integer-types.html" title="13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT">
<code class="literal">
TINYINT
</code>
</a>
, the maximum permissible
sequence number is 127. For
<a class="link" href="integer-types.html" title="13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT">
<code class="literal">
TINYINT
UNSIGNED
</code>
</a>
, the maximum is 255. See
<a class="xref" href="integer-types.html" title="13.1.2 Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT">
Section 13.1.2, “Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT,
MEDIUMINT, BIGINT”
</a>
for the ranges of all the
integer types.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
For a multiple-row insert,
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
and
<a class="ulink" href="/doc/c-api/8.4/en/mysql-insert-id.html" target="_top">
<code class="literal">
mysql_insert_id()
</code>
</a>
actually
return the
<code class="literal">
AUTO_INCREMENT
</code>
key from the
<span class="emphasis">
<em>
first
</em>
</span>
of the inserted rows. This enables
multiple-row inserts to be reproduced correctly on other
servers in a replication setup.
</p>
</div>
<p>
To start with an
<code class="literal">
AUTO_INCREMENT
</code>
value other
than 1, set that value with
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE
TABLE
</code>
</a>
or
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
,
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa48544495"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> tbl <span class="token keyword">AUTO_INCREMENT</span> <span class="token operator">=</span> <span class="token number">100</span><span class="token punctuation">;</span></code></pre>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="example-auto-increment-innodb-notes">
</a>
InnoDB Notes
</h4>
</div>
</div>
</div>
<p>
For information about
<code class="literal">
AUTO_INCREMENT
</code>
usage
specific to
<code class="literal">
InnoDB
</code>
, see
<a class="xref" href="innodb-auto-increment-handling.html" title="17.6.1.6 AUTO_INCREMENT Handling in InnoDB">
Section 17.6.1.6, “AUTO_INCREMENT Handling in InnoDB”
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="example-auto-increment-myisam-notes">
</a>
MyISAM Notes
</h4>
</div>
</div>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For
<code class="literal">
MyISAM
</code>
tables, you can specify
<code class="literal">
AUTO_INCREMENT
</code>
on a secondary column in
a multiple-column index. In this case, the generated value
for the
<code class="literal">
AUTO_INCREMENT
</code>
column is
calculated as
<a class="link" href="aggregate-functions.html#function_max">
<code class="literal">
MAX(
<em class="replaceable">
<code>
auto_increment_column
</code>
</em>
)
+ 1 WHERE
prefix=
<em class="replaceable">
<code>
given-prefix
</code>
</em>
</code>
</a>
.
This is useful when you want to put data into ordered
groups.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81353980"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> animals <span class="token punctuation">(</span>
grp <span class="token datatype">ENUM</span><span class="token punctuation">(</span><span class="token string">'fish'</span><span class="token punctuation">,</span><span class="token string">'mammal'</span><span class="token punctuation">,</span><span class="token string">'bird'</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
id <span class="token datatype">MEDIUMINT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span> <span class="token keyword">AUTO_INCREMENT</span><span class="token punctuation">,</span>
<span class="token keyword">name</span> <span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">30</span><span class="token punctuation">)</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span>
<span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>grp<span class="token punctuation">,</span>id<span class="token punctuation">)</span>
<span class="token punctuation">)</span> <span class="token keyword">ENGINE</span><span class="token operator">=</span>MyISAM<span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> animals <span class="token punctuation">(</span>grp<span class="token punctuation">,</span><span class="token keyword">name</span><span class="token punctuation">)</span> <span class="token keyword">VALUES</span>
<span class="token punctuation">(</span><span class="token string">'mammal'</span><span class="token punctuation">,</span><span class="token string">'dog'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'mammal'</span><span class="token punctuation">,</span><span class="token string">'cat'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token punctuation">(</span><span class="token string">'bird'</span><span class="token punctuation">,</span><span class="token string">'penguin'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'fish'</span><span class="token punctuation">,</span><span class="token string">'lax'</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token string">'mammal'</span><span class="token punctuation">,</span><span class="token string">'whale'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
<span class="token punctuation">(</span><span class="token string">'bird'</span><span class="token punctuation">,</span><span class="token string">'ostrich'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> animals <span class="token keyword">ORDER</span> <span class="token keyword">BY</span> grp<span class="token punctuation">,</span>id<span class="token punctuation">;</span></code></pre>
</div>
<p>
Which returns:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-none"><div class="docs-select-all right" id="sa83059400"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-none">+--------+----+---------+
| grp | id | name |
+--------+----+---------+
| fish | 1 | lax |
| mammal | 1 | dog |
| mammal | 2 | cat |
| mammal | 3 | whale |
| bird | 1 | penguin |
| bird | 2 | ostrich |
+--------+----+---------+</code></pre>
</div>
<p>
In this case (when the
<code class="literal">
AUTO_INCREMENT
</code>
column is part of a multiple-column index),
<code class="literal">
AUTO_INCREMENT
</code>
values are reused if you
delete the row with the biggest
<code class="literal">
AUTO_INCREMENT
</code>
value in any group. This
happens even for
<code class="literal">
MyISAM
</code>
tables, for
which
<code class="literal">
AUTO_INCREMENT
</code>
values normally
are not reused.
</p>
</li>
<li class="listitem">
<p>
If the
<code class="literal">
AUTO_INCREMENT
</code>
column is part of
multiple indexes, MySQL generates sequence values using
the index that begins with the
<code class="literal">
AUTO_INCREMENT
</code>
column, if there is one.
For example, if the
<code class="literal">
animals
</code>
table
contained indexes
<code class="literal">
PRIMARY KEY (grp, id)
</code>
and
<code class="literal">
INDEX (id)
</code>
, MySQL would ignore the
<code class="literal">
PRIMARY KEY
</code>
for generating sequence
values. As a result, the table would contain a single
sequence, not a sequence per
<code class="literal">
grp
</code>
value.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="example-auto-increment-further-reading">
</a>
Further Reading
</h4>
</div>
</div>
</div>
<p>
More information about
<code class="literal">
AUTO_INCREMENT
</code>
is
available here:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
How to assign the
<code class="literal">
AUTO_INCREMENT
</code>
attribute to a column:
<a class="xref" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
Section 15.1.20, “CREATE TABLE Statement”
</a>
, and
<a class="xref" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
Section 15.1.9, “ALTER TABLE Statement”
</a>
.
</p>
</li>
<li class="listitem">
<p>
How
<code class="literal">
AUTO_INCREMENT
</code>
behaves depending on
the
<a class="link" href="sql-mode.html#sqlmode_no_auto_value_on_zero">
<code class="literal">
NO_AUTO_VALUE_ON_ZERO
</code>
</a>
SQL mode:
<a class="xref" href="sql-mode.html" title="7.1.11 Server SQL Modes">
Section 7.1.11, “Server SQL Modes”
</a>
.
</p>
</li>
<li class="listitem">
<p>
How to use the
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
function
to find the row that contains the most recent
<code class="literal">
AUTO_INCREMENT
</code>
value:
<a class="xref" href="information-functions.html" title="14.15 Information Functions">
Section 14.15, “Information Functions”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Setting the
<code class="literal">
AUTO_INCREMENT
</code>
value to be
used:
<a class="xref" href="server-system-variables.html" title="7.1.8 Server System Variables">
Section 7.1.8, “Server System Variables”
</a>
.
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="innodb-auto-increment-handling.html" title="17.6.1.6 AUTO_INCREMENT Handling in InnoDB">
Section 17.6.1.6, “AUTO_INCREMENT Handling in InnoDB”
</a>
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
AUTO_INCREMENT
</code>
and replication:
<a class="xref" href="replication-features-auto-increment.html" title="19.5.1.1 Replication and AUTO_INCREMENT">
Section 19.5.1.1, “Replication and AUTO_INCREMENT”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Server-system variables related to
<code class="literal">
AUTO_INCREMENT
</code>
(
<a class="link" href="replication-options-source.html#sysvar_auto_increment_increment">
<code class="literal">
auto_increment_increment
</code>
</a>
and
<a class="link" href="replication-options-source.html#sysvar_auto_increment_offset">
<code class="literal">
auto_increment_offset
</code>
</a>
)
that can be used for replication:
<a class="xref" href="server-system-variables.html" title="7.1.8 Server System Variables">
Section 7.1.8, “Server System Variables”
</a>
.
</p>
</li>
</ul>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/group-replication-configuring-instances.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="group-replication-configuring-instances">
</a>
20.2.1.2 Configuring an Instance for Group Replication
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045134271264">
</a>
<p>
This section explains the configuration settings required for
MySQL Server instances that you want to use for Group
Replication. For background information, see
<a class="xref" href="group-replication-requirements-and-limitations.html" title="20.3 Requirements and Limitations">
Section 20.3, “Requirements and Limitations”
</a>
.
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="group-replication-configuring-instances.html#group-replication-storage-engines" title="Storage Engines">
Storage Engines
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="group-replication-configuring-instances.html#group-replication-configure-replication-framework" title="Replication Framework">
Replication Framework
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="group-replication-configuring-instances.html#group-replication-configure-plugin" title="Group Replication Settings">
Group Replication Settings
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="group-replication-storage-engines">
</a>
Storage Engines
</h5>
</div>
</div>
</div>
<p>
For Group Replication, data must be stored in the InnoDB
transactional storage engine (for details of why, see
<a class="xref" href="group-replication-requirements.html" title="20.3.1 Group Replication Requirements">
Section 20.3.1, “Group Replication Requirements”
</a>
). The use of
other storage engines, including the temporary
<a class="link" href="memory-storage-engine.html" title="18.3 The MEMORY Storage Engine">
<code class="literal">
MEMORY
</code>
</a>
storage engine, might
cause errors in Group Replication. Set the
<a class="link" href="server-system-variables.html#sysvar_disabled_storage_engines">
<code class="literal">
disabled_storage_engines
</code>
</a>
system variable as follows to prevent their use:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-ini"><div class="docs-select-all right" id="sa24941636"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">disabled_storage_engines</span><span class="token attr-value"><span class="token punctuation">=</span>"MyISAM,BLACKHOLE,FEDERATED,ARCHIVE,MEMORY"</span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="group-replication-configure-replication-framework">
</a>
Replication Framework
</h5>
</div>
</div>
</div>
<p>
The following settings configure replication according to the
MySQL Group Replication requirements.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa33611259"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">server_id</span><span class="token attr-value"><span class="token punctuation">=</span>1</span>
<span class="token constant">gtid_mode</span><span class="token attr-value"><span class="token punctuation">=</span>ON</span>
<span class="token constant">enforce_gtid_consistency</span><span class="token attr-value"><span class="token punctuation">=</span>ON</span></code></pre>
</div>
<p>
These settings configure the server to use the unique
identifier number 1, to enable
<a class="xref" href="replication-gtids.html" title="19.1.3 Replication with Global Transaction Identifiers">
Section 19.1.3, “Replication with Global Transaction Identifiers”
</a>
, and to allow execution of
only statements that can be safely logged using a GTID.
</p>
<p>
This setting disables checksums for events written to the
binary log, which default to being enabled. Group Replication
in MySQL 8.4 supports the presence of checksums
in the binary log and can use them to verify the integrity of
events on some channels, so you can use the default setting.
For more details, see
<a class="xref" href="group-replication-limitations.html" title="20.3.2 Group Replication Limitations">
Section 20.3.2, “Group Replication Limitations”
</a>
.
</p>
<p>
See also
<a class="xref" href="group-replication-requirements.html" title="20.3.1 Group Replication Requirements">
Section 20.3.1, “Group Replication Requirements”
</a>
.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="group-replication-configure-plugin">
</a>
Group Replication Settings
</h5>
</div>
</div>
</div>
<p>
At this point the option file ensures that the server is
configured and is instructed to instantiate the replication
infrastructure under a given configuration. The following
section configures the Group Replication settings for the
server.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-ini"><div class="docs-select-all right" id="sa60074913"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-ini"><span class="token constant">plugin_load_add</span><span class="token attr-value"><span class="token punctuation">=</span>'group_replication.so'</span>
<span class="token constant">group_replication_group_name</span><span class="token attr-value"><span class="token punctuation">=</span>"aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"</span>
<span class="token constant">group_replication_start_on_boot</span><span class="token attr-value"><span class="token punctuation">=</span>off</span>
<span class="token constant">group_replication_local_address</span><span class="token attr-value"><span class="token punctuation">=</span> "s1:33061"</span>
<span class="token constant">group_replication_group_seeds</span><span class="token attr-value"><span class="token punctuation">=</span> "s1:33061,s2:33061,s3:33061"</span>
<span class="token constant">group_replication_bootstrap_group</span><span class="token attr-value"><span class="token punctuation">=</span>off</span></code></pre>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="option">
plugin-load-add
</code>
adds the Group
Replication plugin to the list of plugins which the server
loads at startup. This is preferable in a production
deployment to installing the plugin manually.
</p>
</li>
<li class="listitem">
<p>
Configuring
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_name">
<code class="literal">
group_replication_group_name
</code>
</a>
tells the plugin that the group that it is joining, or
creating, is named
"aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa".
</p>
<p>
The value of
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_name">
<code class="literal">
group_replication_group_name
</code>
</a>
must be a valid UUID. You can use
<code class="literal">
SELECT
UUID()
</code>
to generate one. This UUID forms part of
the GTIDs that are used when transactions received by
group members from clients, and view change events that
are generated internally by the group members, are written
to the binary log.
</p>
</li>
<li class="listitem">
<p>
Configuring the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_start_on_boot">
<code class="literal">
group_replication_start_on_boot
</code>
</a>
variable to
<code class="literal">
off
</code>
instructs the plugin to
not start operations automatically when the server starts.
This is important when setting up Group Replication as it
ensures you can configure the server before manually
starting the plugin. Once the member is configured you can
set
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_start_on_boot">
<code class="literal">
group_replication_start_on_boot
</code>
</a>
to
<code class="literal">
on
</code>
so that Group Replication starts
automatically upon server boot.
</p>
</li>
<li class="listitem">
<p>
Configuring
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
sets the network address and port which the member uses
for internal communication with other members in the
group. Group Replication uses this address for internal
member-to-member connections involving remote instances of
the group communication engine (XCom, a Paxos variant).
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
The group replication local address must be different to
the host name and port used for SQL client connections,
which are defined by MySQL Server's
<a class="link" href="server-system-variables.html#sysvar_hostname">
<code class="literal">
hostname
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_port">
<code class="literal">
port
</code>
</a>
system variables.
It must not be used for client applications. It must be
only be used for internal communication between the
members of the group while running Group Replication.
</p>
</div>
<p>
The network address configured by
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
must be resolvable by all group members. For example, if
each server instance is on a different machine with a
fixed network address, you could use the IP address of the
machine, such as 10.0.0.1. If you use a host name, you
must use a fully qualified name, and ensure it is
resolvable through DNS, correctly configured
<code class="literal">
/etc/hosts
</code>
files, or other name
resolution processes. IPv6 addresses (or host names that
resolve to them) can be used as well as IPv4 addresses; a
group can contain a mix of members using IPv6 and members
using IPv4. For more information on Group Replication
support for IPv6 networks and on mixed IPv4 and IPv6
groups, see
<a class="xref" href="group-replication-ipv6.html" title="20.5.5 Support For IPv6 And For Mixed IPv6 And IPv4 Groups">
Section 20.5.5, “Support For IPv6 And For Mixed IPv6 And IPv4 Groups”
</a>
.
</p>
<p>
The recommended port for
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
is 33061. This is used by Group Replication as the unique
identifier for a group member within the replication
group. You can use the same port for all members of a
replication group as long as the host names or IP
addresses are all different, as demonstrated in this
tutorial. Alternatively you can use the same host name or
IP address for all members as long as the ports are all
different, for example as shown in
<a class="xref" href="group-replication-deploying-locally.html" title="20.2.2 Deploying Group Replication Locally">
Section 20.2.2, “Deploying Group Replication Locally”
</a>
.
</p>
<p>
The connection that an existing member offers to a joining
member for Group Replication's distributed recovery
process is not the network address configured by
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
.
Group members offer their standard SQL client connection
to joining members for distributed recovery, as specified
by MySQL Server's
<a class="link" href="server-system-variables.html#sysvar_hostname">
<code class="literal">
hostname
</code>
</a>
and
<a class="link" href="server-system-variables.html#sysvar_port">
<code class="literal">
port
</code>
</a>
; they may (also)
advertise an alternative list of distributed recovery
endpoints as dedicated client connections for joining
members. For more details, see
<a class="xref" href="group-replication-distributed-recovery-connections.html" title="20.5.4.1 Connections for Distributed Recovery">
Section 20.5.4.1, “Connections for Distributed Recovery”
</a>
.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
Distributed recovery can fail if a joining member cannot
correctly identify the other members using the host name
as defined by MySQL Server's
<a class="link" href="server-system-variables.html#sysvar_hostname">
<code class="literal">
hostname
</code>
</a>
system
variable. It is recommended that operating systems
running MySQL have a properly configured unique host
name, either using DNS or local settings. The host name
that the server is using for SQL client connections can
be verified in the
<code class="literal">
Member_host
</code>
column
of the Performance Schema table
<a class="link" href="performance-schema-replication-group-members-table.html" title="29.12.11.16 The replication_group_members Table">
<code class="literal">
replication_group_members
</code>
</a>
.
If multiple group members externalize a default host
name set by the operating system, there is a chance of
the joining member not resolving it to the correct
member address and not being able to connect for
distributed recovery. In this situation you can use
MySQL Server's
<a class="link" href="replication-options-replica.html#sysvar_report_host">
<code class="literal">
report_host
</code>
</a>
system
variable to configure a unique host name to be
externalized by each of the servers.
</p>
</div>
</li>
<li class="listitem">
<p>
Configuring
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_seeds">
<code class="literal">
group_replication_group_seeds
</code>
</a>
sets the hostname and port of the group members which are
used by the new member to establish its connection to the
group. These members are called the seed members. Once the
connection is established, the group membership
information is listed in the Performance Schema table
<a class="link" href="performance-schema-replication-group-members-table.html" title="29.12.11.16 The replication_group_members Table">
<code class="literal">
replication_group_members
</code>
</a>
.
Usually the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_seeds">
<code class="literal">
group_replication_group_seeds
</code>
</a>
list contains the
<code class="literal">
hostname:port
</code>
of each
of the group member's
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
,
but this is not obligatory and a subset of the group
members can be chosen as seeds.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
The
<code class="literal">
hostname:port
</code>
listed in
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_seeds">
<code class="literal">
group_replication_group_seeds
</code>
</a>
is the seed member's internal network address,
configured by
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
and not the
<code class="literal">
hostname:port
</code>
used for
SQL client connections, which is shown for example in
the Performance Schema table
<a class="link" href="performance-schema-replication-group-members-table.html" title="29.12.11.16 The replication_group_members Table">
<code class="literal">
replication_group_members
</code>
</a>
.
</p>
</div>
<p>
The server that starts the group does not make use of this
option, since it is the initial server and as such, it is
in charge of bootstrapping the group. In other words, any
existing data which is on the server bootstrapping the
group is what is used as the data for the next joining
member. The second server joining asks the one and only
member in the group to join, any missing data on the
second server is replicated from the donor data on the
bootstrapping member, and then the group expands. The
third server joining can ask any of these two to join,
data is synchronized to the new member, and then the group
expands again. Subsequent servers repeat this procedure
when joining.
</p>
<div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Warning
</div>
<p>
When joining multiple servers at the same time, make
sure that they point to seed members that are already in
the group. Do not use members that are also joining the
group as seeds, because they might not yet be in the
group when contacted.
</p>
<p>
It is good practice to start the bootstrap member first,
and let it create the group. Then make it the seed
member for the rest of the members that are joining.
This ensures that there is a group formed when joining
the rest of the members.
</p>
<p>
Creating a group and joining multiple members at the
same time is not supported. It might work, but chances
are that the operations race and then the act of joining
the group ends up in an error or a time out.
</p>
</div>
<p>
A joining member must communicate with a seed member using
the same protocol (IPv4 or IPv6) that the seed member
advertises in the
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_group_seeds">
<code class="literal">
group_replication_group_seeds
</code>
</a>
option. For the purpose of IP address permissions for
Group Replication, the allowlist on the seed member must
include an IP address for the joining member for the
protocol offered by the seed member, or a host name that
resolves to an address for that protocol. This address or
host name must be set up and permitted in addition to the
joining member's
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_local_address">
<code class="literal">
group_replication_local_address
</code>
</a>
if the protocol for that address does not match the seed
member's advertised protocol. If a joining member does not
have a permitted address for the appropriate protocol, its
connection attempt is refused. For more information, see
<a class="xref" href="group-replication-ip-address-permissions.html" title="20.6.4 Group Replication IP Address Permissions">
Section 20.6.4, “Group Replication IP Address Permissions”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Configuring
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_bootstrap_group">
<code class="literal">
group_replication_bootstrap_group
</code>
</a>
instructs the plugin whether to bootstrap the group or
not. In this case, even though s1 is the first member of
the group we set this variable to off in the option file.
Instead we configure
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_bootstrap_group">
<code class="literal">
group_replication_bootstrap_group
</code>
</a>
when the instance is running, to ensure that only one
member actually bootstraps the group.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
The
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_bootstrap_group">
<code class="literal">
group_replication_bootstrap_group
</code>
</a>
variable must only be enabled on one server instance
belonging to a group at any time, usually the first time
you bootstrap the group (or in case the entire group is
brought down and back up again). If you bootstrap the
group multiple times, for example when multiple server
instances have this option set, then they could create
an artificial split brain scenario, in which two
distinct groups with the same name exist. Always set
<a class="link" href="group-replication-system-variables.html#sysvar_group_replication_bootstrap_group">
<code class="literal">
group_replication_bootstrap_group=off
</code>
</a>
after the first server instance comes online.
</p>
</div>
</li>
</ul>
</div>
<p>
The system variables described in this tutorial are the
required configuration settings to start a new member, but
further system variables are also available to configure group
members. These are listed in
<a class="xref" href="group-replication-options.html" title="20.9 Group Replication Variables">
Section 20.9, “Group Replication Variables”
</a>
.
</p>
<div class="important" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Important
</div>
<p>
A number of system variables, some specific to Group
Replication and others not, are group-wide configuration
settings that must have the same value on all group members.
If the group members have a value set for one of these
system variables, and a joining member has a different value
set for it, the joining member cannot join the group and an
error message is returned. If the group members have a value
set for this system variable, and the joining member does
not support the system variable, it cannot join the group.
These system variables are all identified in
<a class="xref" href="group-replication-options.html" title="20.9 Group Replication Variables">
Section 20.9, “Group Replication Variables”
</a>
.
</p>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-ndbinfo-diskpagebuffer.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="mysql-cluster-ndbinfo-diskpagebuffer">
</a>
25.6.17.31 The ndbinfo diskpagebuffer Table
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045089450048">
</a>
<p>
The
<code class="literal">
diskpagebuffer
</code>
table provides statistics
about disk page buffer usage by NDB Cluster Disk Data tables.
</p>
<p>
The
<code class="literal">
diskpagebuffer
</code>
table contains the
following columns:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
node_id
</code>
</p>
<p>
The data node ID
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
block_instance
</code>
</p>
<p>
Block instance
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
pages_written
</code>
</p>
<p>
Number of pages written to disk.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
pages_written_lcp
</code>
</p>
<p>
Number of pages written by local checkpoints.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
pages_read
</code>
</p>
<p>
Number of pages read from disk
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
log_waits
</code>
</p>
<p>
Number of page writes waiting for log to be written to disk
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
page_requests_direct_return
</code>
</p>
<p>
Number of requests for pages that were available in buffer
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
page_requests_wait_queue
</code>
</p>
<p>
Number of requests that had to wait for pages to become
available in buffer
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
page_requests_wait_io
</code>
</p>
<p>
Number of requests that had to be read from pages on disk
(pages were unavailable in buffer)
</p>
</li>
</ul>
</div>
<h5>
<a name="idm46045089428400">
</a>
Notes
</h5>
<p>
You can use this table with NDB Cluster Disk Data tables to
determine whether
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-diskpagebuffermemory">
<code class="literal">
DiskPageBufferMemory
</code>
</a>
is
sufficiently large to allow data to be read from the buffer
rather from disk; minimizing disk seeks can help improve
performance of such tables.
</p>
<p>
You can determine the proportion of reads from
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-diskpagebuffermemory">
<code class="literal">
DiskPageBufferMemory
</code>
</a>
to
the total number of reads using a query such as this one, which
obtains this ratio as a percentage:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96163295"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span>
node_id<span class="token punctuation">,</span>
<span class="token number">100</span> <span class="token operator">*</span> page_requests_direct_return <span class="token operator">/</span>
<span class="token punctuation">(</span>page_requests_direct_return <span class="token operator">+</span> page_requests_wait_io<span class="token punctuation">)</span>
<span class="token keyword">AS</span> hit_ratio
<span class="token keyword">FROM</span> ndbinfo<span class="token punctuation">.</span>diskpagebuffer<span class="token punctuation">;</span></code></pre>
</div>
<p>
The result from this query should be similar to what is shown
here, with one row for each data node in the cluster (in this
example, the cluster has 4 data nodes):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa7522426"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> node_id <span class="token punctuation">|</span> hit_ratio <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 5 <span class="token punctuation">|</span> 97.6744 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 6 <span class="token punctuation">|</span> 97.6879 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 7 <span class="token punctuation">|</span> 98.1776 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 8 <span class="token punctuation">|</span> 98.1343 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">4 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
<code class="literal">
hit_ratio
</code>
values approaching 100% indicate
that only a very small number of reads are being made from disk
rather than from the buffer, which means that Disk Data read
performance is approaching an optimum level. If any of these
values are less than 95%, this is a strong indicator that the
setting for
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-diskpagebuffermemory">
<code class="literal">
DiskPageBufferMemory
</code>
</a>
needs to be increased in the
<code class="filename">
config.ini
</code>
file.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
A change in
<a class="link" href="mysql-cluster-ndbd-definition.html#ndbparam-ndbd-diskpagebuffermemory">
<code class="literal">
DiskPageBufferMemory
</code>
</a>
requires a rolling restart of all of the cluster's data
nodes before it takes effect.
</p>
</div>
<p>
<code class="literal">
block_instance
</code>
refers to an instance of a
kernel block. Together with the block name, this number can be
used to look up a given instance in the
<a class="link" href="mysql-cluster-ndbinfo-threadblocks.html" title="25.6.17.62 The ndbinfo threadblocks Table">
<code class="literal">
threadblocks
</code>
</a>
table. Using this
information, you can obtain information about disk page buffer
metrics relating to individual threads; an example query using
<code class="literal">
LIMIT 1
</code>
to limit the output to a single
thread is shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa95476951"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span>
<span class="token operator">></span> node_id<span class="token punctuation">,</span> thr_no<span class="token punctuation">,</span> block_name<span class="token punctuation">,</span> thread_name<span class="token punctuation">,</span> pages_written<span class="token punctuation">,</span>
<span class="token operator">></span> pages_written_lcp<span class="token punctuation">,</span> pages_read<span class="token punctuation">,</span> log_waits<span class="token punctuation">,</span>
<span class="token operator">></span> page_requests_direct_return<span class="token punctuation">,</span> page_requests_wait_queue<span class="token punctuation">,</span>
<span class="token operator">></span> page_requests_wait_io
<span class="token operator">></span> <span class="token keyword">FROM</span> ndbinfo<span class="token punctuation">.</span>diskpagebuffer
<span class="token operator">></span> <span class="token keyword">INNER</span> <span class="token keyword">JOIN</span> ndbinfo<span class="token punctuation">.</span>threadblocks <span class="token keyword">USING</span> <span class="token punctuation">(</span>node_id<span class="token punctuation">,</span> block_instance<span class="token punctuation">)</span>
<span class="token operator">></span> <span class="token keyword">INNER</span> <span class="token keyword">JOIN</span> ndbinfo<span class="token punctuation">.</span>threads <span class="token keyword">USING</span> <span class="token punctuation">(</span>node_id<span class="token punctuation">,</span> thr_no<span class="token punctuation">)</span>
<span class="token operator">></span> <span class="token keyword">WHERE</span> block_name <span class="token operator">=</span> <span class="token string">'PGMAN'</span> <span class="token keyword">LIMIT</span> <span class="token number">1</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
node_id<span class="token punctuation">:</span> 1
thr_no<span class="token punctuation">:</span> 1
block_name<span class="token punctuation">:</span> PGMAN
thread_name<span class="token punctuation">:</span> rep
pages_written<span class="token punctuation">:</span> 0
pages_written_lcp<span class="token punctuation">:</span> 0
pages_read<span class="token punctuation">:</span> 1
log_waits<span class="token punctuation">:</span> 0
page_requests_direct_return<span class="token punctuation">:</span> 4
page_requests_wait_queue<span class="token punctuation">:</span> 0
page_requests_wait_io<span class="token punctuation">:</span> 1
</span><span class="token output">1 row in set (0.01 sec)</span></code></pre>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/sys-format-time.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="sys-format-time">
</a>
30.4.5.6 The format_time() Function
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045060951616">
</a>
<a class="indexterm" name="idm46045060950160">
</a>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<a class="link" href="sys-format-time.html" title="30.4.5.6 The format_time() Function">
<code class="literal">
format_time()
</code>
</a>
is deprecated,
and subject to removal in a future MySQL version.
Applications that use it should be migrated to use the
built-in
<a class="link" href="performance-schema-functions.html#function_format-pico-time">
<code class="literal">
FORMAT_PICO_TIME()
</code>
</a>
function instead. See
<a class="xref" href="performance-schema-functions.html" title="14.21 Performance Schema Functions">
Section 14.21, “Performance Schema Functions”
</a>
</p>
</div>
<p>
Given a Performance Schema latency or wait time in
picoseconds, converts it to human-readable format and returns
a string consisting of a value and a units indicator.
Depending on the size of the value, the units part is
<code class="literal">
ps
</code>
(picoseconds),
<code class="literal">
ns
</code>
(nanoseconds),
<code class="literal">
us
</code>
(microseconds),
<code class="literal">
ms
</code>
(milliseconds),
<code class="literal">
s
</code>
(seconds),
<code class="literal">
m
</code>
(minutes),
<code class="literal">
h
</code>
(hours),
<code class="literal">
d
</code>
(days), or
<code class="literal">
w
</code>
(weeks).
</p>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-time-parameters">
</a>
Parameters
</h5>
</div>
</div>
</div>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<code class="literal">
picoseconds TEXT
</code>
: The picoseconds
value to format.
</p>
</li>
</ul>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-time-return-value">
</a>
Return Value
</h5>
</div>
</div>
</div>
<p>
A
<code class="literal">
TEXT
</code>
value.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h5 class="title">
<a name="sys-format-time-example">
</a>
Example
</h5>
</div>
</div>
</div>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa8758880"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> sys<span class="token punctuation">.</span>format_time<span class="token punctuation">(</span><span class="token number">3501</span><span class="token punctuation">)</span><span class="token punctuation">,</span> sys<span class="token punctuation">.</span>format_time<span class="token punctuation">(</span><span class="token number">188732396662000</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> sys.format_time(3501) <span class="token punctuation">|</span> sys.format_time(188732396662000) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 3.50 ns <span class="token punctuation">|</span> 3.15 m <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/insert-on-duplicate.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="insert-on-duplicate">
</a>
15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement
</h4>
</div>
</div>
</div>
<p>
If you specify an
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
clause and a row to be inserted would cause a duplicate value in
a
<code class="literal">
UNIQUE
</code>
index or
<code class="literal">
PRIMARY
KEY
</code>
, an
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
of the
old row occurs. For example, if column
<code class="literal">
a
</code>
is
declared as
<code class="literal">
UNIQUE
</code>
and contains the value
<code class="literal">
1
</code>
, the following two statements have similar
effect:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa59006052"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c<span class="token operator">=</span>c<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span>
<span class="token keyword">UPDATE</span> t1 <span class="token keyword">SET</span> c<span class="token operator">=</span>c<span class="token operator">+</span><span class="token number">1</span> <span class="token keyword">WHERE</span> a<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The effects are not quite identical: For an
<code class="literal">
InnoDB
</code>
table where
<code class="literal">
a
</code>
is an
auto-increment column, the
<code class="literal">
INSERT
</code>
statement
increases the auto-increment value but the
<code class="literal">
UPDATE
</code>
does not.
</p>
<p>
If column
<code class="literal">
b
</code>
is also unique, the
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
is equivalent to this
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
statement instead:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa15446400"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">UPDATE</span> t1 <span class="token keyword">SET</span> c<span class="token operator">=</span>c<span class="token operator">+</span><span class="token number">1</span> <span class="token keyword">WHERE</span> a<span class="token operator">=</span><span class="token number">1</span> <span class="token operator">OR</span> b<span class="token operator">=</span><span class="token number">2</span> <span class="token keyword">LIMIT</span> <span class="token number">1</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
If
<code class="literal">
a=1 OR b=2
</code>
matches several rows, only
<span class="emphasis">
<em>
one
</em>
</span>
row is updated. In general, you should
try to avoid using an
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
clause on tables with multiple unique indexes.
</p>
<p>
With
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
, the
affected-rows value per row is 1 if the row is inserted as a new
row, 2 if an existing row is updated, and 0 if an existing row
is set to its current values. If you specify the
<code class="literal">
CLIENT_FOUND_ROWS
</code>
flag to the
<a class="ulink" href="/doc/c-api/8.4/en/mysql-real-connect.html" target="_top">
<code class="literal">
mysql_real_connect()
</code>
</a>
C API
function when connecting to
<a class="link" href="mysqld.html" title="6.3.1 mysqld — The MySQL Server">
<span class="command">
<strong>
mysqld
</strong>
</span>
</a>
, the
affected-rows value is 1 (not 0) if an existing row is set to
its current values.
</p>
<p>
If a table contains an
<code class="literal">
AUTO_INCREMENT
</code>
column
and
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT
... ON DUPLICATE KEY UPDATE
</code>
</a>
inserts or updates a row,
the
<a class="link" href="information-functions.html#function_last-insert-id">
<code class="literal">
LAST_INSERT_ID()
</code>
</a>
function
returns the
<code class="literal">
AUTO_INCREMENT
</code>
value.
</p>
<p>
The
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
clause can
contain multiple column assignments, separated by commas.
</p>
<p>
It is possible to use
<code class="literal">
IGNORE
</code>
with
<code class="literal">
ON
DUPLICATE KEY UPDATE
</code>
in an
<code class="literal">
INSERT
</code>
statement, but this may not behave as you expect when inserting
multiple rows into a table that has multiple unique keys. This
becomes apparent when an updated value is itself a duplicate key
value. Consider the table
<code class="literal">
t
</code>
, created and
populated by the statements shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa44163582"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t <span class="token punctuation">(</span>a <span class="token keyword">SERIAL</span><span class="token punctuation">,</span> b <span class="token datatype">BIGINT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span> <span class="token keyword">UNIQUE</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>b<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.03 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 2 rows affected (0.01 sec)</span>
<span class="token output">Records: 2 Duplicates: 0 Warnings: 0</span>
<span class="token prompt">mysql></span> <span class="token keyword">TABLE</span> t<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> b <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
Now we attempt to insert two rows, one of which contains a
duplicate key value, using
<code class="literal">
ON DUPLICATE KEY
UPDATE
</code>
, where the
<code class="literal">
UPDATE
</code>
clause
itself results in a duplicate key value:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa41392532"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span> <span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> a<span class="token operator">=</span>a<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">,</span> b<span class="token operator">=</span>b<span class="token number">-1</span><span class="token punctuation">;</span>
<span class="token output">ERROR 1062 (23000)<span class="token punctuation">:</span> Duplicate entry '1' for key 't.b'</span>
<span class="token prompt">mysql></span> <span class="token keyword">TABLE</span> t<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> b <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">2 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
The first row contains a duplicate value for one of the
table's unique keys (column
<code class="literal">
a
</code>
), but
<code class="literal">
b=b+1
</code>
in the
<code class="literal">
UPDATE
</code>
clause
results in a unique key violation for column
<code class="literal">
b
</code>
; the statement is immediately rejected with
an error, and no rows are updated. Let us repeat the statement,
this time adding the
<strong class="userinput">
<code>
IGNORE
</code>
</strong>
keyword, like
this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa32389108"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">IGNORE</span> <span class="token keyword">INTO</span> t <span class="token keyword">VALUES</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span>
<span class="token prompt"> -></span> <span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> a<span class="token operator">=</span>a<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">,</span> b<span class="token operator">=</span>b<span class="token number">-1</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 1 row affected, 1 warning (0.00 sec)</span>
<span class="token output">Records: 2 Duplicates: 1 Warnings: 1</span></code></pre>
</div>
<p>
This time, the previous error is demoted to a warning, as shown
here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81096315"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Level <span class="token punctuation">|</span> Code <span class="token punctuation">|</span> Message <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Warning <span class="token punctuation">|</span> 1062 <span class="token punctuation">|</span> Duplicate entry '1' for key 't.b' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span></code></pre>
</div>
<p>
Because the statement was not rejected, execution continues.
This means that the second row is inserted into
<code class="literal">
t
</code>
, as we can see here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa7370420"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">TABLE</span> t<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> b <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 2 <span class="token punctuation">|</span> 2 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> 3 <span class="token punctuation">|</span> 3 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">3 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
In assignment value expressions in the
<code class="literal">
ON DUPLICATE KEY
UPDATE
</code>
clause, you can use the
<a class="link" href="miscellaneous-functions.html#function_values">
<code class="literal">
VALUES(
<em class="replaceable">
<code>
col_name
</code>
</em>
)
</code>
</a>
function to refer to column values from the
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
portion of the
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT ...
ON DUPLICATE KEY UPDATE
</code>
</a>
statement. In other words,
<a class="link" href="miscellaneous-functions.html#function_values">
<code class="literal">
VALUES(
<em class="replaceable">
<code>
col_name
</code>
</em>
)
</code>
</a>
in the
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
clause refers
to the value of
<em class="replaceable">
<code>
col_name
</code>
</em>
that would
be inserted, had no duplicate-key conflict occurred. This
function is especially useful in multiple-row inserts. The
<a class="link" href="miscellaneous-functions.html#function_values">
<code class="literal">
VALUES()
</code>
</a>
function is meaningful
only as an introducer for
<code class="literal">
INSERT
</code>
statement
value lists, or in the
<code class="literal">
ON DUPLICATE KEY
UPDATE
</code>
clause of an
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
statement, and returns
<code class="literal">
NULL
</code>
otherwise. For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa71383506"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c<span class="token operator">=</span><span class="token keyword">VALUES</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token operator">+</span><span class="token keyword">VALUES</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
That statement is identical to the following two statements:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa66883053"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c<span class="token operator">=</span><span class="token number">3</span><span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c<span class="token operator">=</span><span class="token number">9</span><span class="token punctuation">;</span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
The use of
<a class="link" href="miscellaneous-functions.html#function_values">
<code class="literal">
VALUES()
</code>
</a>
to refer to
the new row and columns is deprecated, and subject to removal
in a future version of MySQL. Instead, use row and column
aliases, as described in the next few paragraphs of this
section.
</p>
</div>
<p>
It is possible to use an alias for the row, with, optionally,
one or more of its columns to be inserted, following the
<code class="literal">
VALUES
</code>
or
<code class="literal">
SET
</code>
clause, and
preceded by the
<code class="literal">
AS
</code>
keyword. Using the row
alias
<code class="literal">
new
</code>
, the statement shown previously
using
<code class="literal">
VALUES()
</code>
to access the new column
values can be written in the form shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa13369123"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> <span class="token keyword">new</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c <span class="token operator">=</span> <span class="token keyword">new</span><span class="token punctuation">.</span>a<span class="token operator">+</span><span class="token keyword">new</span><span class="token punctuation">.</span>b<span class="token punctuation">;</span></code></pre>
</div>
<p>
If, in addition, you use the column aliases
<code class="literal">
m
</code>
,
<code class="literal">
n
</code>
, and
<code class="literal">
p
</code>
, you can omit the row alias in the
assignment clause and write the same statement like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa38535964"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">,</span>c<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token number">6</span><span class="token punctuation">)</span> <span class="token keyword">AS</span> <span class="token keyword">new</span><span class="token punctuation">(</span>m<span class="token punctuation">,</span>n<span class="token punctuation">,</span>p<span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c <span class="token operator">=</span> m<span class="token operator">+</span>n<span class="token punctuation">;</span></code></pre>
</div>
<p>
When using column aliases in this fashion, you must still use a
row alias following the
<code class="literal">
VALUES
</code>
clause, even
if you do not make direct use of it in the assignment clause.
</p>
<p>
An
<code class="literal">
INSERT ... SELECT ... ON DUPLICATE KEY
UPDATE
</code>
statement that uses
<code class="literal">
VALUES()
</code>
in the
<code class="literal">
UPDATE
</code>
clause, like this one, throws a
warning:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa20452088"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1
<span class="token keyword">SELECT</span> c<span class="token punctuation">,</span> c<span class="token operator">+</span>d <span class="token keyword">FROM</span> t2
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> b <span class="token operator">=</span> <span class="token keyword">VALUES</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
You can eliminate such warnings by using a subquery instead,
like this:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa41828373"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> c<span class="token punctuation">,</span> c<span class="token operator">+</span>d <span class="token keyword">AS</span> e <span class="token keyword">FROM</span> t2<span class="token punctuation">)</span> <span class="token keyword">AS</span> dt
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> b <span class="token operator">=</span> e<span class="token punctuation">;</span></code></pre>
</div>
<p>
You can also use row and column aliases with a
<code class="literal">
SET
</code>
clause, as mentioned previously.
Employing
<code class="literal">
SET
</code>
instead of
<code class="literal">
VALUES
</code>
in the two
<code class="literal">
INSERT ... ON
DUPLICATE KEY UPDATE
</code>
statements just shown can be done
as shown here:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa95135256"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">SET</span> a<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">,</span>b<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span>c<span class="token operator">=</span><span class="token number">3</span> <span class="token keyword">AS</span> <span class="token keyword">new</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c <span class="token operator">=</span> <span class="token keyword">new</span><span class="token punctuation">.</span>a<span class="token operator">+</span><span class="token keyword">new</span><span class="token punctuation">.</span>b<span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">SET</span> a<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">,</span>b<span class="token operator">=</span><span class="token number">2</span><span class="token punctuation">,</span>c<span class="token operator">=</span><span class="token number">3</span> <span class="token keyword">AS</span> <span class="token keyword">new</span><span class="token punctuation">(</span>m<span class="token punctuation">,</span>n<span class="token punctuation">,</span>p<span class="token punctuation">)</span>
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> c <span class="token operator">=</span> m<span class="token operator">+</span>n<span class="token punctuation">;</span></code></pre>
</div>
<p>
The row alias must not be the same as the name of the table. If
column aliases are not used, or if they are the same as the
column names, they must be distinguished using the row alias in
the
<code class="literal">
ON DUPLICATE KEY UPDATE
</code>
clause. Column
aliases must be unique with regard to the row alias to which
they apply (that is, no column aliases referring to columns of
the same row may be the same).
</p>
<p>
For
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT
... SELECT
</code>
</a>
statements, these rules apply regarding
acceptable forms of
<code class="literal">
SELECT
</code>
query expressions
that you can refer to in an
<code class="literal">
ON DUPLICATE KEY
UPDATE
</code>
clause:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
References to columns from queries on a single table, which
may be a derived table.
</p>
</li>
<li class="listitem">
<p>
References to columns from queries on a join over multiple
tables.
</p>
</li>
<li class="listitem">
<p>
References to columns from
<code class="literal">
DISTINCT
</code>
queries.
</p>
</li>
<li class="listitem">
<p>
References to columns in other tables, as long as the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
does not use
<code class="literal">
GROUP BY
</code>
. One side effect is that you
must qualify references to nonunique column names.
</p>
</li>
</ul>
</div>
<p>
References to columns from a
<a class="link" href="union.html" title="15.2.18 UNION Clause">
<code class="literal">
UNION
</code>
</a>
are not supported. To work
around this restriction, rewrite the
<a class="link" href="union.html" title="15.2.18 UNION Clause">
<code class="literal">
UNION
</code>
</a>
as a derived table so that
its rows can be treated as a single-table result set. For
example, this statement produces an error:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa25552272"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span>
<span class="token keyword">SELECT</span> c<span class="token punctuation">,</span> d <span class="token keyword">FROM</span> t2
<span class="token keyword">UNION</span>
<span class="token keyword">SELECT</span> e<span class="token punctuation">,</span> f <span class="token keyword">FROM</span> t3
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> b <span class="token operator">=</span> b <span class="token operator">+</span> c<span class="token punctuation">;</span></code></pre>
</div>
<p>
Instead, use an equivalent statement that rewrites the
<a class="link" href="union.html" title="15.2.18 UNION Clause">
<code class="literal">
UNION
</code>
</a>
as a derived table:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa65484287"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> c<span class="token punctuation">,</span> d <span class="token keyword">FROM</span> t2
<span class="token keyword">UNION</span>
<span class="token keyword">SELECT</span> e<span class="token punctuation">,</span> f <span class="token keyword">FROM</span> t3<span class="token punctuation">)</span> <span class="token keyword">AS</span> dt
<span class="token keyword">ON</span> <span class="token keyword">DUPLICATE</span> <span class="token keyword">KEY</span> <span class="token keyword">UPDATE</span> b <span class="token operator">=</span> b <span class="token operator">+</span> c<span class="token punctuation">;</span></code></pre>
</div>
<p>
The technique of rewriting a query as a derived table also
enables references to columns from
<code class="literal">
GROUP BY
</code>
queries.
</p>
<p>
Because the results of
<a class="link" href="insert-select.html" title="15.2.7.1 INSERT ... SELECT Statement">
<code class="literal">
INSERT ...
SELECT
</code>
</a>
statements depend on the ordering of rows from
the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
and this order cannot
always be guaranteed, it is possible when logging
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT ...
SELECT ON DUPLICATE KEY UPDATE
</code>
</a>
statements for the
source and the replica to diverge. Thus,
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT ...
SELECT ON DUPLICATE KEY UPDATE
</code>
</a>
statements are flagged
as unsafe for statement-based replication. Such statements
produce a warning in the error log when using statement-based
mode and are written to the binary log using the row-based
format when using
<code class="literal">
MIXED
</code>
mode. An
<a class="link" href="insert-on-duplicate.html" title="15.2.7.2 INSERT ... ON DUPLICATE KEY UPDATE Statement">
<code class="literal">
INSERT ...
ON DUPLICATE KEY UPDATE
</code>
</a>
statement against a table
having more than one unique or primary key is also marked as
unsafe. (Bug #11765650, Bug #58637)
</p>
<p>
See also
<a class="xref" href="replication-sbr-rbr.html" title="19.2.1.1 Advantages and Disadvantages of Statement-Based and Row-Based Replication">
Section 19.2.1.1, “Advantages and Disadvantages of Statement-Based and Row-Based
Replication”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-backups-mysqldump.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="replication-solutions-backups-mysqldump">
</a>
19.4.1.1 Backing Up a Replica Using mysqldump
</h4>
</div>
</div>
</div>
<p>
Using
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
to create a copy of a
database enables you to capture all of the data in the database
in a format that enables the information to be imported into
another instance of MySQL Server (see
<a class="xref" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
Section 6.5.4, “mysqldump — A Database Backup Program”
</a>
). Because the format of the
information is SQL statements, the file can easily be
distributed and applied to running servers in the event that you
need access to the data in an emergency. However, if the size of
your data set is very large,
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
may be
impractical.
</p>
<div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Tip
</div>
<p>
Consider using the
<a class="ulink" href="/doc/mysql-shell/8.4/en/mysql-shell-utilities-dump-instance-schema.html" target="_top">
MySQL Shell dump utilities
</a>
, which provide parallel dumping with multiple threads, file compression, and progress information display, as well as cloud features such as Oracle Cloud Infrastructure Object Storage streaming, and MySQL HeatWave Service compatibility checks and modifications. Dumps can be easily imported into a MySQL Server instance or a MySQL HeatWave Service DB System using the
<a class="ulink" href="/doc/mysql-shell/8.4/en/mysql-shell-utilities-load-dump.html" target="_top">
MySQL Shell load dump utilities
</a>
. Installation instructions for MySQL Shell can be found
<a class="ulink" href="/doc/mysql-shell/8.4/en/mysql-shell-install.html" target="_top">
here
</a>
.
</p>
</div>
<p>
When using
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
, you should stop
replication on the replica before starting the dump process to
ensure that the dump contains a consistent set of data:
</p>
<div class="orderedlist">
<ol class="orderedlist" type="1">
<li class="listitem">
<p>
Stop the replica from processing requests. You can stop
replication completely on the replica using
<a class="link" href="mysqladmin.html" title="6.5.2 mysqladmin — A MySQL Server Administration Program">
<span class="command">
<strong>
mysqladmin
</strong>
</span>
</a>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa8257958"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqladmin</span> stop-replica</code></pre>
</div>
<p>
Alternatively, you can stop only the replication SQL thread
to pause event execution:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa58383647"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysql</span> <span class="token property">-e</span> <span class="token atrule">'STOP REPLICA SQL_THREAD;'</span></code></pre>
</div>
<p>
This enables the replica to continue to receive data change
events from the source's binary log and store them in the
relay logs using the replication receiver thread, but
prevents the replica from executing these events and
changing its data. Within busy replication environments,
permitting the replication receiver thread to run during
backup may speed up the catch-up process when you restart
the replication applier thread.
</p>
</li>
<li class="listitem">
<p>
Run
<a class="link" href="mysqldump.html" title="6.5.4 mysqldump — A Database Backup Program">
<span class="command">
<strong>
mysqldump
</strong>
</span>
</a>
to dump your databases. You
may either dump all databases or select databases to be
dumped. For example, to dump all databases:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa1448280"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqldump</span> <span class="token property">--all-databases</span> > fulldb<span class="token punctuation">.</span>dump</code></pre>
</div>
</li>
<li class="listitem">
<p>
Once the dump has completed, start replication again:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-terminal"><div class="docs-select-all right" id="sa76738624"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-terminal"><span class="token prompt">$> </span><span class="token command">mysqladmin</span> start-replica</code></pre>
</div>
</li>
</ol>
</div>
<p>
In the preceding example, you may want to add login credentials
(user name, password) to the commands, and bundle the process up
into a script that you can run automatically each day.
</p>
<p>
If you use this approach, make sure you monitor the replication
process to ensure that the time taken to run the backup does not
affect the replica's ability to keep up with events from the
source. See
<a class="xref" href="replication-administration-status.html" title="19.1.7.1 Checking Replication Status">
Section 19.1.7.1, “Checking Replication Status”
</a>
.
If the replica is unable to keep up, you may want to add another
replica and distribute the backup process. For an example of how
to configure this scenario, see
<a class="xref" href="replication-solutions-partitioning.html" title="19.4.6 Replicating Different Databases to Different Replicas">
Section 19.4.6, “Replicating Different Databases to Different Replicas”
</a>
.
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/charset-binary-collations.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="charset-binary-collations">
</a>
12.8.5 The binary Collation Compared to _bin Collations
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045217020496">
</a>
<a class="indexterm" name="idm46045217019424">
</a>
<a class="indexterm" name="idm46045217017936">
</a>
<a class="indexterm" name="idm46045217016864">
</a>
<p>
This section describes how the
<code class="literal">
binary
</code>
collation for binary strings compares to
<code class="literal">
_bin
</code>
collations for nonbinary strings.
</p>
<p>
Binary strings (as stored using the
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
BINARY
</code>
</a>
,
<a class="link" href="binary-varbinary.html" title="13.3.3 The BINARY and VARBINARY Types">
<code class="literal">
VARBINARY
</code>
</a>
, and
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
BLOB
</code>
</a>
data types) have a character
set and collation named
<code class="literal">
binary
</code>
. Binary
strings are sequences of bytes and the numeric values of those
bytes determine comparison and sort order. See
<a class="xref" href="charset-binary-set.html" title="12.10.8 The Binary Character Set">
Section 12.10.8, “The Binary Character Set”
</a>
.
</p>
<p>
Nonbinary strings (as stored using the
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
CHAR
</code>
</a>
,
<a class="link" href="char.html" title="13.3.2 The CHAR and VARCHAR Types">
<code class="literal">
VARCHAR
</code>
</a>
, and
<a class="link" href="blob.html" title="13.3.4 The BLOB and TEXT Types">
<code class="literal">
TEXT
</code>
</a>
data types) have a character
set and collation other than
<code class="literal">
binary
</code>
. A given
nonbinary character set can have several collations, each of
which defines a particular comparison and sort order for the
characters in the set. For most character sets, one of these is
the binary collation, indicated by a
<code class="literal">
_bin
</code>
suffix in the collation name. For example, the binary collations
for
<code class="literal">
latin1
</code>
and
<code class="literal">
big5
</code>
are
named
<code class="literal">
latin1_bin
</code>
and
<code class="literal">
big5_bin
</code>
, respectively.
<code class="literal">
utf8mb4
</code>
is an exception that has two binary
collations,
<code class="literal">
utf8mb4_bin
</code>
and
<code class="literal">
utf8mb4_0900_bin
</code>
; see
<a class="xref" href="charset-unicode-sets.html" title="12.10.1 Unicode Character Sets">
Section 12.10.1, “Unicode Character Sets”
</a>
.
</p>
<p>
The
<code class="literal">
binary
</code>
collation differs from
<code class="literal">
_bin
</code>
collations in several respects,
discussed in the following sections:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
<a class="xref" href="charset-binary-collations.html#charset-binary-collations-comparison-units" title="The Unit for Comparison and Sorting">
The Unit for Comparison and Sorting
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="charset-binary-collations.html#charset-binary-collations-charset-conversion" title="Character Set Conversion">
Character Set Conversion
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="charset-binary-collations.html#charset-binary-collations-lettercase-conversion" title="Lettercase Conversion">
Lettercase Conversion
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="charset-binary-collations.html#charset-binary-collations-trailing-space-comparisons" title="Trailing Space Handling in Comparisons">
Trailing Space Handling in Comparisons
</a>
</p>
</li>
<li class="listitem">
<p>
<a class="xref" href="charset-binary-collations.html#charset-binary-collations-trailing-space-inserts-retrievals" title="Trailing Space Handling for Inserts and Retrievals">
Trailing Space Handling for Inserts and Retrievals
</a>
</p>
</li>
</ul>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="charset-binary-collations-comparison-units">
</a>
The Unit for Comparison and Sorting
</h4>
</div>
</div>
</div>
<p>
Binary strings are sequences of bytes. For the
<code class="literal">
binary
</code>
collation, comparison and sorting
are based on numeric byte values. Nonbinary strings are
sequences of characters, which might be multibyte. Collations
for nonbinary strings define an ordering of the character
values for comparison and sorting. For
<code class="literal">
_bin
</code>
collations, this ordering is based on numeric character code
values, which is similar to ordering for binary strings except
that character code values might be multibyte.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="charset-binary-collations-charset-conversion">
</a>
Character Set Conversion
</h4>
</div>
</div>
</div>
<p>
A nonbinary string has a character set and is automatically
converted to another character set in many cases, even when
the string has a
<code class="literal">
_bin
</code>
collation:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
When assigning column values to another column that has a
different character set:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa19430897"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">UPDATE</span> t1 <span class="token keyword">SET</span> utf8mb4_bin_column<span class="token operator">=</span>latin1_column<span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>latin1_column<span class="token punctuation">)</span> <span class="token keyword">SELECT</span> utf8mb4_bin_column <span class="token keyword">FROM</span> t2<span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
When assigning column values for
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
or
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
using a string
literal:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa36274693"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">NAMES</span> latin1<span class="token punctuation">;</span>
<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token punctuation">(</span>utf8mb4_bin_column<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token string">'string-in-latin1'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
</li>
<li class="listitem">
<p>
When sending results from the server to a client:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa55516445"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SET</span> <span class="token keyword">NAMES</span> latin1<span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> utf8mb4_bin_column <span class="token keyword">FROM</span> t2<span class="token punctuation">;</span></code></pre>
</div>
</li>
</ul>
</div>
<p>
For binary string columns, no conversion occurs. For cases
similar to those preceding, the string value is copied
byte-wise.
</p>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="charset-binary-collations-lettercase-conversion">
</a>
Lettercase Conversion
</h4>
</div>
</div>
</div>
<p>
Collations for nonbinary character sets provide information
about lettercase of characters, so characters in a nonbinary
string can be converted from one lettercase to another, even
for
<code class="literal">
_bin
</code>
collations that ignore lettercase
for ordering:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa26206441"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">NAMES</span> utf8mb4 <span class="token keyword">COLLATE</span> utf8mb4_bin<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">LOWER</span><span class="token punctuation">(</span><span class="token string">'aA'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token function">UPPER</span><span class="token punctuation">(</span><span class="token string">'zZ'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> LOWER('aA') <span class="token punctuation">|</span> UPPER('zZ') <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> aa <span class="token punctuation">|</span> ZZ <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<p>
The concept of lettercase does not apply to bytes in a binary
string. To perform lettercase conversion, the string must
first be converted to a nonbinary string using a character set
appropriate for the data stored in the string:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa5305550"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">NAMES</span> <span class="token datatype">binary</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token function">LOWER</span><span class="token punctuation">(</span><span class="token string">'aA'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token function">LOWER</span><span class="token punctuation">(</span><span class="token function">CONVERT</span><span class="token punctuation">(</span><span class="token string">'aA'</span> <span class="token keyword">USING</span> utf8mb4<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> LOWER('aA') <span class="token punctuation">|</span> LOWER(CONVERT('aA' USING utf8mb4)) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> aA <span class="token punctuation">|</span> aa <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="charset-binary-collations-trailing-space-comparisons">
</a>
Trailing Space Handling in Comparisons
</h4>
</div>
</div>
</div>
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</a>
<a class="indexterm" name="idm46045216961952">
</a>
<a class="indexterm" name="idm46045216960464">
</a>
<a class="indexterm" name="idm46045216958976">
</a>
<a class="indexterm" name="idm46045216957488">
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</a>
<p>
MySQL collations have a pad attribute, which has a value of
<code class="literal">
PAD SPACE
</code>
or
<code class="literal">
NO PAD
</code>
:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
Most MySQL collations have a pad attribute of
<code class="literal">
PAD
SPACE
</code>
.
</p>
</li>
<li class="listitem">
<p>
The Unicode collations based on UCA 9.0.0 and higher have
a pad attribute of
<code class="literal">
NO PAD
</code>
; see
<a class="xref" href="charset-unicode-sets.html" title="12.10.1 Unicode Character Sets">
Section 12.10.1, “Unicode Character Sets”
</a>
.
</p>
</li>
</ul>
</div>
<p>
For nonbinary strings (
<code class="literal">
CHAR
</code>
,
<code class="literal">
VARCHAR
</code>
, and
<code class="literal">
TEXT
</code>
values), the string collation pad attribute determines
treatment in comparisons of trailing spaces at the end of
strings:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
For
<code class="literal">
PAD SPACE
</code>
collations, trailing
spaces are insignificant in comparisons; strings are
compared without regard to trailing spaces.
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
NO PAD
</code>
collations treat trailing spaces
as significant in comparisons, like any other character.
</p>
</li>
</ul>
</div>
<p>
The differing behaviors can be demonstrated using the two
<code class="literal">
utf8mb4
</code>
binary collations, one of which is
<code class="literal">
PAD SPACE
</code>
, the other of which is
<code class="literal">
NO PAD
</code>
. The example also shows how to use
the
<code class="literal">
INFORMATION_SCHEMA
</code>
<a class="link" href="information-schema-collations-table.html" title="28.3.6 The INFORMATION_SCHEMA COLLATIONS Table">
<code class="literal">
COLLATIONS
</code>
</a>
table to determine the
pad attribute for collations.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa88397106"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> COLLATION_NAME<span class="token punctuation">,</span> PAD_ATTRIBUTE
<span class="token keyword">FROM</span> INFORMATION_SCHEMA<span class="token punctuation">.</span>COLLATIONS
<span class="token keyword">WHERE</span> COLLATION_NAME <span class="token operator">LIKE</span> <span class="token string">'utf8mb4%bin'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> COLLATION_NAME <span class="token punctuation">|</span> PAD_ATTRIBUTE <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> utf8mb4_bin <span class="token punctuation">|</span> PAD SPACE <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> utf8mb4_0900_bin <span class="token punctuation">|</span> NO PAD <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">NAMES</span> utf8mb4 <span class="token keyword">COLLATE</span> utf8mb4_bin<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token string">'a '</span> <span class="token operator">=</span> <span class="token string">'a'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 'a ' = 'a' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">NAMES</span> utf8mb4 <span class="token keyword">COLLATE</span> utf8mb4_0900_bin<span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token string">'a '</span> <span class="token operator">=</span> <span class="token string">'a'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 'a ' = 'a' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<div class="admon-title">
Note
</div>
<p>
<span class="quote">
“
<span class="quote">
Comparison
</span>
”
</span>
in this context does not include
the
<a class="link" href="string-comparison-functions.html#operator_like">
<code class="literal">
LIKE
</code>
</a>
pattern-matching
operator, for which trailing spaces are significant,
regardless of collation.
</p>
</div>
<p>
For binary strings (
<code class="literal">
BINARY
</code>
,
<code class="literal">
VARBINARY
</code>
, and
<code class="literal">
BLOB
</code>
values), all bytes are significant in comparisons, including
trailing spaces:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa96651854"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> <span class="token keyword">NAMES</span> <span class="token datatype">binary</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token string">'a '</span> <span class="token operator">=</span> <span class="token string">'a'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 'a ' = 'a' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
<div class="simplesect">
<div class="titlepage">
<div>
<div class="simple">
<h4 class="title">
<a name="charset-binary-collations-trailing-space-inserts-retrievals">
</a>
Trailing Space Handling for Inserts and Retrievals
</h4>
</div>
</div>
</div>
<p>
<code class="literal">
CHAR(
<em class="replaceable">
<code>
N
</code>
</em>
)
</code>
columns
store nonbinary strings
<em class="replaceable">
<code>
N
</code>
</em>
characters long. For inserts, values shorter than
<em class="replaceable">
<code>
N
</code>
</em>
characters are extended with
spaces. For retrievals, trailing spaces are removed.
</p>
<p>
<code class="literal">
BINARY(
<em class="replaceable">
<code>
N
</code>
</em>
)
</code>
columns store binary strings
<em class="replaceable">
<code>
N
</code>
</em>
bytes long. For inserts, values shorter than
<em class="replaceable">
<code>
N
</code>
</em>
bytes are extended with
<code class="literal">
0x00
</code>
bytes. For retrievals, nothing is
removed; a value of the declared length is always returned.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa81658707"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>
a <span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span> <span class="token keyword">CHARACTER</span> <span class="token keyword">SET</span> utf8mb4 <span class="token keyword">COLLATE</span> utf8mb4_bin<span class="token punctuation">,</span>
b <span class="token datatype">BINARY</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">)</span>
<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token string">'x'</span><span class="token punctuation">,</span><span class="token string">'x'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token string">'x '</span><span class="token punctuation">,</span><span class="token string">'x '</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> <span class="token function">HEX</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token function">HEX</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span> <span class="token keyword">FROM</span> t1<span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> a <span class="token punctuation">|</span> b <span class="token punctuation">|</span> HEX(a) <span class="token punctuation">|</span> HEX(b) <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> x <span class="token punctuation">|</span> 0x78000000000000000000 <span class="token punctuation">|</span> 78 <span class="token punctuation">|</span> 78000000000000000000 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">|</span> x <span class="token punctuation">|</span> 0x78200000000000000000 <span class="token punctuation">|</span> 78 <span class="token punctuation">|</span> 78200000000000000000 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span></code></pre>
</div>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/show-warnings.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="show-warnings">
</a>
15.7.7.42 SHOW WARNINGS Statement
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045168963904">
</a>
<a class="indexterm" name="idm46045168962832">
</a>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa16487968"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span> <span class="token punctuation">[</span><span class="token keyword">LIMIT</span> <span class="token punctuation">[</span><span class="token keyword"><em class="replaceable">offset</em></span><span class="token punctuation">,</span><span class="token punctuation">]</span> <span class="token keyword"><em class="replaceable">row_count</em></span><span class="token punctuation">]</span>
<span class="token keyword">SHOW</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">WARNINGS</span></code></pre>
</div>
<p>
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW WARNINGS
</code>
</a>
is a diagnostic
statement that displays information about the conditions
(errors, warnings, and notes) resulting from executing a
statement in the current session. Warnings are generated for DML
statements such as
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
,
<a class="link" href="update.html" title="15.2.17 UPDATE Statement">
<code class="literal">
UPDATE
</code>
</a>
, and
<a class="link" href="load-data.html" title="15.2.9 LOAD DATA Statement">
<code class="literal">
LOAD DATA
</code>
</a>
as well as DDL
statements such as
<a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
<code class="literal">
CREATE TABLE
</code>
</a>
and
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER TABLE
</code>
</a>
.
</p>
<p>
The
<code class="literal">
LIMIT
</code>
clause has the same syntax as for
the
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement. See
<a class="xref" href="select.html" title="15.2.13 SELECT Statement">
Section 15.2.13, “SELECT Statement”
</a>
.
</p>
<p>
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW WARNINGS
</code>
</a>
is also used
following
<a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
<code class="literal">
EXPLAIN
</code>
</a>
, to display the
extended information generated by
<a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
<code class="literal">
EXPLAIN
</code>
</a>
. See
<a class="xref" href="explain-extended.html" title="10.8.3 Extended EXPLAIN Output Format">
Section 10.8.3, “Extended EXPLAIN Output Format”
</a>
.
</p>
<p>
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW WARNINGS
</code>
</a>
displays
information about the conditions resulting from execution of the
most recent nondiagnostic statement in the current session. If
the most recent statement resulted in an error during parsing,
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW WARNINGS
</code>
</a>
shows the resulting
conditions, regardless of statement type (diagnostic or
nondiagnostic).
</p>
<p>
The
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW COUNT(*)
WARNINGS
</code>
</a>
diagnostic statement displays the total
number of errors, warnings, and notes. You can also retrieve
this number from the
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
system variable:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa43342381"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SHOW</span> <span class="token function">COUNT</span><span class="token punctuation">(</span><span class="token operator">*</span><span class="token punctuation">)</span> <span class="token keyword">WARNINGS</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token variable">@@warning_count</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
A difference in these statements is that the first is a
diagnostic statement that does not clear the message list. The
second, because it is a
<a class="link" href="select.html" title="15.2.13 SELECT Statement">
<code class="literal">
SELECT
</code>
</a>
statement is considered nondiagnostic and does clear the message
list.
</p>
<p>
A related diagnostic statement,
<a class="link" href="show-errors.html" title="15.7.7.18 SHOW ERRORS Statement">
<code class="literal">
SHOW
ERRORS
</code>
</a>
, shows only error conditions (it excludes
warnings and notes), and
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW COUNT(*)
ERRORS
</code>
</a>
statement displays the total number of errors.
See
<a class="xref" href="show-errors.html" title="15.7.7.18 SHOW ERRORS Statement">
Section 15.7.7.18, “SHOW ERRORS Statement”
</a>
.
<a class="link" href="get-diagnostics.html" title="15.6.7.3 GET DIAGNOSTICS Statement">
<code class="literal">
GET
DIAGNOSTICS
</code>
</a>
can be used to examine information for
individual conditions. See
<a class="xref" href="get-diagnostics.html" title="15.6.7.3 GET DIAGNOSTICS Statement">
Section 15.6.7.3, “GET DIAGNOSTICS Statement”
</a>
.
</p>
<p>
Here is a simple example that shows data-conversion warnings for
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
. The example assumes that
strict SQL mode is disabled. With strict mode enabled, the
warnings would become errors and terminate the
<a class="link" href="insert.html" title="15.2.7 INSERT Statement">
<code class="literal">
INSERT
</code>
</a>
.
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa26844419"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> t1 <span class="token punctuation">(</span>a <span class="token datatype">TINYINT</span> <span class="token operator">NOT</span> <span class="token boolean">NULL</span><span class="token punctuation">,</span> b <span class="token datatype">CHAR</span><span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.05 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> t1 <span class="token keyword">VALUES</span><span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span><span class="token string">'mysql'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token boolean">NULL</span><span class="token punctuation">,</span><span class="token string">'test'</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token punctuation">(</span><span class="token number">300</span><span class="token punctuation">,</span><span class="token string">'xyz'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 3 rows affected, 3 warnings (0.00 sec)</span>
<span class="token output">Records: 3 Duplicates: 0 Warnings: 3</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Level<span class="token punctuation">:</span> Warning
Code<span class="token punctuation">:</span> 1265
Message<span class="token punctuation">:</span> Data truncated for column 'b' at row 1
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 2. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Level<span class="token punctuation">:</span> Warning
Code<span class="token punctuation">:</span> 1048
Message<span class="token punctuation">:</span> Column 'a' cannot be null
<span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 3. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
Level<span class="token punctuation">:</span> Warning
Code<span class="token punctuation">:</span> 1264
Message<span class="token punctuation">:</span> Out of range value for column 'a' at row 3
</span><span class="token output">3 rows in set (0.00 sec)</span></code></pre>
</div>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
system
variable controls the maximum number of error, warning, and note
messages for which the server stores information, and thus the
number of messages that
<a class="link" href="show-warnings.html" title="15.7.7.42 SHOW WARNINGS Statement">
<code class="literal">
SHOW
WARNINGS
</code>
</a>
displays. To change the number of messages
the server can store, change the value of
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
.
</p>
<p>
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
controls only
how many messages are stored, not how many are counted. The
value of
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
is not
limited by
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
,
even if the number of messages generated exceeds
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
. The following
example demonstrates this. The
<a class="link" href="alter-table.html" title="15.1.9 ALTER TABLE Statement">
<code class="literal">
ALTER
TABLE
</code>
</a>
statement produces three warning messages
(strict SQL mode is disabled for the example to prevent an error
from occurring after a single conversion issue). Only one
message is stored and displayed because
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
has been set to
1, but all three are counted (as shown by the value of
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa89056037"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">VARIABLES</span> <span class="token operator">LIKE</span> <span class="token string">'max_error_count'</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Variable_name <span class="token punctuation">|</span> Value <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> max_error_count <span class="token punctuation">|</span> 1024 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> max_error_count<span class="token operator">=</span><span class="token number">1</span><span class="token punctuation">,</span> sql_mode <span class="token operator">=</span> <span class="token string">''</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> t1 <span class="token keyword">MODIFY</span> b <span class="token datatype">CHAR</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 3 rows affected, 3 warnings (0.00 sec)</span>
<span class="token output">Records: 3 Duplicates: 0 Warnings: 3</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Level <span class="token punctuation">|</span> Code <span class="token punctuation">|</span> Message <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Warning <span class="token punctuation">|</span> 1263 <span class="token punctuation">|</span> Data truncated for column 'b' at row 1 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token variable">@@warning_count</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> @@warning_count <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 3 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.01 sec)</span></code></pre>
</div>
<p>
To disable message storage, set
<a class="link" href="server-system-variables.html#sysvar_max_error_count">
<code class="literal">
max_error_count
</code>
</a>
to 0. In this
case,
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
still
indicates how many warnings occurred, but messages are not
stored and cannot be displayed.
</p>
<p>
The
<a class="link" href="server-system-variables.html#sysvar_sql_notes">
<code class="literal">
sql_notes
</code>
</a>
system variable
controls whether note messages increment
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
and whether the
server stores them. By default,
<a class="link" href="server-system-variables.html#sysvar_sql_notes">
<code class="literal">
sql_notes
</code>
</a>
is 1, but if set to
0, notes do not increment
<a class="link" href="server-system-variables.html#sysvar_warning_count">
<code class="literal">
warning_count
</code>
</a>
and the server
does not store them:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa32211030"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> <span class="token keyword">SET</span> sql_notes <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">DROP</span> <span class="token keyword">TABLE</span> <span class="token keyword">IF</span> <span class="token keyword">EXISTS</span> test<span class="token punctuation">.</span>no_such_table<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected, 1 warning (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Level <span class="token punctuation">|</span> Code <span class="token punctuation">|</span> Message <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> Note <span class="token punctuation">|</span> 1051 <span class="token punctuation">|</span> Unknown table 'test.no_such_table' <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SET</span> sql_notes <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span>
<span class="token prompt">mysql></span> <span class="token keyword">DROP</span> <span class="token keyword">TABLE</span> <span class="token keyword">IF</span> <span class="token keyword">EXISTS</span> test<span class="token punctuation">.</span>no_such_table<span class="token punctuation">;</span>
<span class="token output">Query OK, 0 rows affected (0.00 sec)</span>
<span class="token prompt">mysql></span> <span class="token keyword">SHOW</span> <span class="token keyword">WARNINGS</span><span class="token punctuation">;</span>
<span class="token output">Empty set (0.00 sec)</span></code></pre>
</div>
<p>
The MySQL server sends to each client a count indicating the
total number of errors, warnings, and notes resulting from the
most recent statement executed by that client. From the C API,
this value can be obtained by calling
<a class="ulink" href="/doc/c-api/8.4/en/mysql-warning-count.html" target="_top">
<code class="literal">
mysql_warning_count()
</code>
</a>
. See
<a class="ulink" href="/doc/c-api/8.4/en/mysql-warning-count.html" target="_top">
mysql_warning_count()
</a>
.
</p>
<p>
In the
<a class="link" href="mysql.html" title="6.5.1 mysql — The MySQL Command-Line Client">
<span class="command">
<strong>
mysql
</strong>
</span>
</a>
client, you can enable and
disable automatic warnings display using the
<code class="literal">
warnings
</code>
and
<code class="literal">
nowarning
</code>
commands, respectively, or their shortcuts,
<code class="literal">
\W
</code>
and
<code class="literal">
\w
</code>
(see
<a class="xref" href="mysql-commands.html" title="6.5.1.2 mysql Client Commands">
Section 6.5.1.2, “mysql Client Commands”
</a>
). For example:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa42761718"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql></span> \W
<span class="token keyword">Show</span> <span class="token keyword">warnings</span> enabled<span class="token punctuation">.</span>
<span class="token prompt">mysql></span> <span class="token keyword">SELECT</span> <span class="token number">1</span><span class="token operator">/</span><span class="token number">0</span><span class="token punctuation">;</span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> 1/0 <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output"><span class="token punctuation">|</span> NULL <span class="token punctuation">|</span></span>
<span class="token output"><span class="token punctuation">+</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">-</span><span class="token punctuation">+</span></span>
<span class="token output">1 row in set, 1 warning (0.03 sec)</span>
Warning <span class="token punctuation">(</span><span class="token keyword">Code</span> <span class="token number">1365</span><span class="token punctuation">)</span>: Division <span class="token keyword">by</span> <span class="token number">0</span>
<span class="token prompt">mysql></span> \w
<span class="token keyword">Show</span> <span class="token keyword">warnings</span> disabled<span class="token punctuation">.</span></code></pre>
</div>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/row-subqueries.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h4 class="title">
<a name="row-subqueries">
</a>
15.2.15.5 Row Subqueries
</h4>
</div>
</div>
</div>
<a class="indexterm" name="idm46045179918704">
</a>
<a class="indexterm" name="idm46045179917632">
</a>
<a class="indexterm" name="idm46045179916592">
</a>
<a class="indexterm" name="idm46045179915520">
</a>
<p>
Scalar or column subqueries return a single value or a column of
values. A
<span class="emphasis">
<em>
row subquery
</em>
</span>
is a subquery
variant that returns a single row and can thus return more than
one column value. Legal operators for row subquery comparisons
are:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa1425441"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token operator">=</span> <span class="token operator">></span> <span class="token operator"><</span> <span class="token operator">>=</span> <span class="token operator"><=</span> <span class="token operator"><></span> <span class="token operator">!=</span> <span class="token operator"><=></span></code></pre>
</div>
<p>
Here are two examples:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa50997061"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1
<span class="token keyword">WHERE</span> <span class="token punctuation">(</span>col1<span class="token punctuation">,</span>col2<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> col3<span class="token punctuation">,</span> col4 <span class="token keyword">FROM</span> t2 <span class="token keyword">WHERE</span> id <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1
<span class="token keyword">WHERE</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span>col1<span class="token punctuation">,</span>col2<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> col3<span class="token punctuation">,</span> col4 <span class="token keyword">FROM</span> t2 <span class="token keyword">WHERE</span> id <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
For both queries, if the table
<code class="literal">
t2
</code>
contains a
single row with
<code class="literal">
id = 10
</code>
, the subquery returns
a single row. If this row has
<code class="literal">
col3
</code>
and
<code class="literal">
col4
</code>
values equal to the
<code class="literal">
col1
</code>
and
<code class="literal">
col2
</code>
values of
any rows in
<code class="literal">
t1
</code>
, the
<code class="literal">
WHERE
</code>
expression is
<code class="literal">
TRUE
</code>
and each query returns
those
<code class="literal">
t1
</code>
rows. If the
<code class="literal">
t2
</code>
row
<code class="literal">
col3
</code>
and
<code class="literal">
col4
</code>
values
are not equal the
<code class="literal">
col1
</code>
and
<code class="literal">
col2
</code>
values of any
<code class="literal">
t1
</code>
row,
the expression is
<code class="literal">
FALSE
</code>
and the query returns
an empty result set. The expression is
<span class="emphasis">
<em>
unknown
</em>
</span>
(that is,
<code class="literal">
NULL
</code>
)
if the subquery produces no rows. An error occurs if the
subquery produces multiple rows because a row subquery can
return at most one row.
</p>
<p>
For information about how each operator works for row
comparisons, see
<a class="xref" href="comparison-operators.html" title="14.4.2 Comparison Functions and Operators">
Section 14.4.2, “Comparison Functions and Operators”
</a>
.
</p>
<p>
The expressions
<code class="literal">
(1,2)
</code>
and
<code class="literal">
ROW(1,2)
</code>
are sometimes called
<span class="firstterm">
row constructors
</span>
. The two
are equivalent. The row constructor and the row returned by the
subquery must contain the same number of values.
</p>
<p>
A row constructor is used for comparisons with subqueries that
return two or more columns. When a subquery returns a single
column, this is regarded as a scalar value and not as a row, so
a row constructor cannot be used with a subquery that does not
return at least two columns. Thus, the following query fails
with a syntax error:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa14776059"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> <span class="token keyword">ROW</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token keyword">SELECT</span> column1 <span class="token keyword">FROM</span> t2<span class="token punctuation">)</span></code></pre>
</div>
<p>
Row constructors are legal in other contexts. For example, the
following two statements are semantically equivalent (and are
handled in the same way by the optimizer):
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa59912864"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> <span class="token punctuation">(</span>column1<span class="token punctuation">,</span>column2<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> t1 <span class="token keyword">WHERE</span> column1 <span class="token operator">=</span> <span class="token number">1</span> <span class="token operator">AND</span> column2 <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
The following query answers the request,
<span class="quote">
“
<span class="quote">
find all rows in
table
<code class="literal">
t1
</code>
that also exist in table
<code class="literal">
t2
</code>
</span>
”
</span>
:
</p>
<div class="copytoclipboard-wrapper">
<pre class="programlisting language-sql"><div class="docs-select-all right" id="sa66758527"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">SELECT</span> column1<span class="token punctuation">,</span>column2<span class="token punctuation">,</span>column3
<span class="token keyword">FROM</span> t1
<span class="token keyword">WHERE</span> <span class="token punctuation">(</span>column1<span class="token punctuation">,</span>column2<span class="token punctuation">,</span>column3<span class="token punctuation">)</span> <span class="token keyword">IN</span>
<span class="token punctuation">(</span><span class="token keyword">SELECT</span> column1<span class="token punctuation">,</span>column2<span class="token punctuation">,</span>column3 <span class="token keyword">FROM</span> t2<span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
</div>
<p>
For more information about the optimizer and row constructors,
see
<a class="xref" href="row-constructor-optimization.html" title="10.2.1.22 Row Constructor Expression Optimization">
Section 10.2.1.22, “Row Constructor Expression Optimization”
</a>
</p>
</div>
<br/>
</div>
|
https://dev.mysql.com/doc/refman/8.4/en/charset-collation-names.html | <div id="docs-body">
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title">
<a name="charset-collation-names">
</a>
12.3.1 Collation Naming Conventions
</h3>
</div>
</div>
</div>
<a class="indexterm" name="idm46045217948640">
</a>
<p>
MySQL collation names follow these conventions:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
A collation name starts with the name of the character set
with which it is associated, generally followed by one or
more suffixes indicating other collation characteristics.
For example,
<code class="literal">
utf8mb4_0900_ai_ci
</code>
and
<code class="literal">
latin1_swedish_ci
</code>
are collations for the
<code class="literal">
utf8mb4
</code>
and
<code class="literal">
latin1
</code>
character sets, respectively. The
<code class="literal">
binary
</code>
character set has a single collation, also named
<code class="literal">
binary
</code>
, with no suffixes.
</p>
</li>
<li class="listitem">
<p>
A language-specific collation includes a locale code or
language name. For example,
<code class="literal">
utf8mb4_tr_0900_ai_ci
</code>
and
<code class="literal">
utf8mb4_hu_0900_ai_ci
</code>
sort characters for
the
<code class="literal">
utf8mb4
</code>
character set using the rules
of Turkish and Hungarian, respectively.
<code class="literal">
utf8mb4_turkish_ci
</code>
and
<code class="literal">
utf8mb4_hungarian_ci
</code>
are similar but
based on a less recent version of the Unicode Collation
Algorithm.
</p>
</li>
<li class="listitem">
<p>
Collation suffixes indicate whether a collation is
case-sensitive, accent-sensitive, or kana-sensitive (or some
combination thereof), or binary. The following table shows
the suffixes used to indicate these characteristics.
</p>
<a class="indexterm" name="idm46045217935344">
</a>
<a class="indexterm" name="idm46045217934272">
</a>
<a class="indexterm" name="idm46045217932784">
</a>
<a class="indexterm" name="idm46045217931712">
</a>
<a class="indexterm" name="idm46045217930224">
</a>
<a class="indexterm" name="idm46045217929152">
</a>
<a class="indexterm" name="idm46045217927664">
</a>
<a class="indexterm" name="idm46045217926592">
</a>
<a class="indexterm" name="idm46045217925104">
</a>
<a class="indexterm" name="idm46045217924032">
</a>
<a class="indexterm" name="idm46045217922544">
</a>
<a class="indexterm" name="idm46045217921472">
</a>
<div class="table">
<a name="charset-collation-sensitivity-suffixes">
</a>
<p class="title">
<b>
Table 12.1 Collation Suffix Meanings
</b>
</p>
<div class="table-contents">
<table summary="Collation suffixes that indicate lettercase sensitivity, accent sensitivity, kana sensitivity, binary.">
<colgroup>
<col style="width: 20%"/>
<col style="width: 80%"/>
</colgroup>
<thead>
<tr>
<th>
Suffix
</th>
<th>
Meaning
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<code class="literal">
_ai
</code>
</td>
<td>
Accent-insensitive
</td>
</tr>
<tr>
<td>
<code class="literal">
_as
</code>
</td>
<td>
Accent-sensitive
</td>
</tr>
<tr>
<td>
<code class="literal">
_ci
</code>
</td>
<td>
Case-insensitive
</td>
</tr>
<tr>
<td>
<code class="literal">
_cs
</code>
</td>
<td>
Case-sensitive
</td>
</tr>
<tr>
<td>
<code class="literal">
_ks
</code>
</td>
<td>
Kana-sensitive
</td>
</tr>
<tr>
<td>
<code class="literal">
_bin
</code>
</td>
<td>
Binary
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>
For nonbinary collation names that do not specify accent
sensitivity, it is determined by case sensitivity. If a
collation name does not contain
<code class="literal">
_ai
</code>
or
<code class="literal">
_as
</code>
,
<code class="literal">
_ci
</code>
in the name
implies
<code class="literal">
_ai
</code>
and
<code class="literal">
_cs
</code>
in
the name implies
<code class="literal">
_as
</code>
. For example,
<code class="literal">
latin1_general_ci
</code>
is explicitly
case-insensitive and implicitly accent-insensitive,
<code class="literal">
latin1_general_cs
</code>
is explicitly
case-sensitive and implicitly accent-sensitive, and
<code class="literal">
utf8mb4_0900_ai_ci
</code>
is explicitly
case-insensitive and accent-insensitive.
</p>
<p>
For Japanese collations, the
<code class="literal">
_ks
</code>
suffix
indicates that a collation is kana-sensitive; that is, it
distinguishes Katakana characters from Hiragana characters.
Japanese collations without the
<code class="literal">
_ks
</code>
suffix are not kana-sensitive and treat Katakana and
Hiragana characters equal for sorting.
</p>
<p>
For the
<code class="literal">
binary
</code>
collation of the
<code class="literal">
binary
</code>
character set, comparisons are
based on numeric byte values. For the
<code class="literal">
_bin
</code>
collation of a nonbinary character
set, comparisons are based on numeric character code values,
which differ from byte values for multibyte characters. For
information about the differences between the
<code class="literal">
binary
</code>
collation of the
<code class="literal">
binary
</code>
character set and the
<code class="literal">
_bin
</code>
collations of nonbinary character
sets, see
<a class="xref" href="charset-binary-collations.html" title="12.8.5 The binary Collation Compared to _bin Collations">
Section 12.8.5, “The binary Collation Compared to _bin Collations”
</a>
.
</p>
</li>
<li class="listitem">
<p>
Collation names for Unicode character sets may include a
version number to indicate the version of the Unicode
Collation Algorithm (UCA) on which the collation is based.
UCA-based collations without a version number in the name
use the version-4.0.0 UCA weight keys. For example:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
<p>
<code class="literal">
utf8mb4_0900_ai_ci
</code>
is based on UCA
9.0.0 weight keys
(
<a class="ulink" href="http://www.unicode.org/Public/UCA/9.0.0/allkeys.txt" target="_blank">
http://www.unicode.org/Public/UCA/9.0.0/allkeys.txt
</a>
).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf8mb4_unicode_520_ci
</code>
is based on
UCA 5.2.0 weight keys
(
<a class="ulink" href="http://www.unicode.org/Public/UCA/5.2.0/allkeys.txt" target="_blank">
http://www.unicode.org/Public/UCA/5.2.0/allkeys.txt
</a>
).
</p>
</li>
<li class="listitem">
<p>
<code class="literal">
utf8mb4_unicode_ci
</code>
(with no version
named) is based on UCA 4.0.0 weight keys
(
<a class="ulink" href="http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt" target="_blank">
http://www.unicode.org/Public/UCA/4.0.0/allkeys-4.0.0.txt
</a>
).
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
For Unicode character sets, the
<code class="literal">
<em class="replaceable">
<code>
xxx
</code>
</em>
_general_mysql500_ci
</code>
collations preserve the pre-5.1.24 ordering of the original
<code class="literal">
<em class="replaceable">
<code>
xxx
</code>
</em>
_general_ci
</code>
collations and permit upgrades for tables created before
MySQL 5.1.24 (Bug #27877).
</p>
</li>
</ul>
</div>
</div>
<br/>
</div>
|
Subsets and Splits