title: Wordpress error establishing a database connection - Memory Issue
body: <p>I have been running this wordpress site for a long time with no issues, however have recently been getting the error "Error establishing a database connection". If I restart mySQL the problem is temporarily fixed but will soon comes back.</p>
  
  <p>After looking through the MySQL log files I believe the problem is because of some sort of memory leak, however I am having trouble tracking down the root of the problem.</p>
  
  <p>I have read that the problem could be coming from a swapfile not being configured, however I have configured the swap as follows:</p>
  
  <pre><code>             total       used       free     shared    buffers     cached
  Mem:           987        968         18         26         18        137
  -/+ buffers/cache:        812        175
  Swap:          255         35        220
  </code></pre>
  
  <p>It would be awesome if anyone could help me make sense of this log file.</p>
  
  <p>MySQL Log File:</p>
  
  <pre><code>2016-03-17 06:48:45 3575 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
  2016-03-17 06:48:45 3575 [Note] Plugin 'FEDERATED' is disabled.
  2016-03-17 06:48:45 3575 [ERROR] Function 'innodb' already exists
  2016-03-17 06:48:45 3575 [Warning] Couldn't load plugin named 'innodb' with soname 'ha_innodb.so'.
  2016-03-17 06:48:45 3575 [ERROR] Function 'federated' already exists
  2016-03-17 06:48:45 3575 [Warning] Couldn't load plugin named 'federated' with soname 'ha_federated.so'.
  2016-03-17 06:48:45 3575 [ERROR] Function 'blackhole' already exists
  2016-03-17 06:48:45 3575 [Warning] Couldn't load plugin named 'blackhole' with soname 'ha_blackhole.so'.
  2016-03-17 06:48:45 3575 [ERROR] Function 'archive' already exists
  2016-03-17 06:48:45 3575 [Warning] Couldn't load plugin named 'archive' with soname 'ha_archive.so'.
  2016-03-17 06:48:45 3575 [Note] InnoDB: Using atomics to ref count buffer pool pages
  2016-03-17 06:48:45 3575 [Note] InnoDB: The InnoDB memory heap is disabled
  2016-03-17 06:48:45 3575 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
  2016-03-17 06:48:45 3575 [Note] InnoDB: Memory barrier is not used
  2016-03-17 06:48:45 3575 [Note] InnoDB: Compressed tables use zlib 1.2.8
  2016-03-17 06:48:45 3575 [Note] InnoDB: Using Linux native AIO
  2016-03-17 06:48:45 3575 [Note] InnoDB: Using CPU crc32 instructions
  2016-03-17 06:48:45 3575 [Note] InnoDB: Initializing buffer pool, size = 128.0M
  InnoDB: mmap(137363456 bytes) failed; errno 12
  2016-03-17 06:48:45 3575 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
  2016-03-17 06:48:45 3575 [ERROR] Plugin 'InnoDB' init function returned error.
  2016-03-17 06:48:45 3575 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
  2016-03-17 06:48:45 3575 [ERROR] Unknown/unsupported storage engine: InnoDB
  2016-03-17 06:48:45 3575 [ERROR] Aborting
  
  2016-03-17 06:48:45 3575 [Note] Binlog end
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'partition'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'BLACKHOLE'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'ARCHIVE'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'PERFORMANCE_SCHEMA'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_DATAFILES'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_TABLESPACES'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN_COLS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_FOREIGN'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_FIELDS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_COLUMNS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_INDEXES'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_TABLESTATS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_SYS_TABLES'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_INDEX_TABLE'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_INDEX_CACHE'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_CONFIG'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_BEING_DELETED'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_DELETED'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_FT_DEFAULT_STOPWORD'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_METRICS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_BUFFER_POOL_STATS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE_LRU'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_BUFFER_PAGE'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX_RESET'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMP_PER_INDEX'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMPMEM_RESET'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMPMEM'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMP_RESET'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_CMP'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_LOCK_WAITS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_LOCKS'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'INNODB_TRX'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'CSV'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'MEMORY'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'MRG_MYISAM'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'MyISAM'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'sha256_password'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'mysql_old_password'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'mysql_native_password'
  2016-03-17 06:48:45 3575 [Note] Shutting down plugin 'binlog'
  2016-03-17 06:48:45 3575 [Note] /usr/sbin/mysqld: Shutdown complete
  
  2016-03-17 06:48:46 3606 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
  2016-03-17 06:48:46 3606 [Note] Plugin 'FEDERATED' is disabled.
  2016-03-17 06:48:46 3606 [ERROR] Function 'innodb' already exists
  2016-03-17 06:48:46 3606 [Warning] Couldn't load plugin named 'innodb' with soname 'ha_innodb.so'.
  2016-03-17 06:48:46 3606 [ERROR] Function 'federated' already exists
  2016-03-17 06:48:46 3606 [Warning] Couldn't load plugin named 'federated' with soname 'ha_federated.so'.
  2016-03-17 06:48:46 3606 [ERROR] Function 'blackhole' already exists
  2016-03-17 06:48:46 3606 [Warning] Couldn't load plugin named 'blackhole' with soname 'ha_blackhole.so'.
  2016-03-17 06:48:46 3606 [ERROR] Function 'archive' already exists
  2016-03-17 06:48:46 3606 [Warning] Couldn't load plugin named 'archive' with soname 'ha_archive.so'.
  2016-03-17 06:48:46 3606 [Note] InnoDB: Using atomics to ref count buffer pool pages
  2016-03-17 06:48:46 3606 [Note] InnoDB: The InnoDB memory heap is disabled
  2016-03-17 06:48:46 3606 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
  2016-03-17 06:48:46 3606 [Note] InnoDB: Memory barrier is not used
  2016-03-17 06:48:46 3606 [Note] InnoDB: Compressed tables use zlib 1.2.8
  2016-03-17 06:48:46 3606 [Note] InnoDB: Using Linux native AIO
  2016-03-17 06:48:46 3606 [Note] InnoDB: Using CPU crc32 instructions
  2016-03-17 06:48:46 3606 [Note] InnoDB: Initializing buffer pool, size = 128.0M
  InnoDB: mmap(137363456 bytes) failed; errno 12
  2016-03-17 06:48:46 3606 [ERROR] InnoDB: Cannot allocate memory for the buffer pool
  2016-03-17 06:48:46 3606 [ERROR] Plugin 'InnoDB' init function returned error.
  2016-03-17 06:48:46 3606 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
  2016-03-17 06:48:46 3606 [ERROR] Unknown/unsupported storage engine: InnoDB
  2016-03-17 06:48:46 3606 [ERROR] Aborting
  </code></pre>