title: SQL error while installing OTRS5
body: <p>I need your help, i am upgrading OTRS4 to OTRS5 on a centos7 in my company and i have an issue with the database migration step 6.2</p>
  
  <p><a href="https://otrs.github.io/doc/manual/admin/5.0/en/html/upgrading.html" rel="nofollow">https://otrs.github.io/doc/manual/admin/5.0/en/html/upgrading.html</a></p>
  
  <p>It's a perl script that update the old otrs database </p>
  
  <p>Here's what i got i run the script:</p>
  
  <pre><code>root@otrs:cat /opt/otrs/scripts/DBUpdate-to-5.pl | mysql -p -f -u root otrs5
  Enter password:
  ERROR 1061 (42000) at line 4: Duplicate key name 'link_relation_list_source'
  ERROR 1061 (42000) at line 5: Duplicate key name 'link_relation_list_target'
  ERROR 1050 (42S01) at line 9: Table 'scheduler_task' already exists
  ERROR 1050 (42S01) at line 28: Table 'scheduler_future_task' already exists
  ERROR 1050 (42S01) at line 47: Table 'scheduler_recurrent_task' already exists
  ERROR 1091 (42000) at line 68: Can't DROP 'text2'; check that column/key exists
  ERROR 1050 (42S01) at line 72: Table 'notification_event_message' already exists
  ERROR 1050 (42S01) at line 87: Table 'cloud_service_config' already exists
  ERROR 1005 (HY000) at line 101: Can't create table 'otrs5.#sql-918_f727' (errno: 121)
  ERROR 1005 (HY000) at line 102: Can't create table 'otrs5.#sql-918_f727' (errno: 121)
  ERROR 1005 (HY000) at line 103: Can't create table 'otrs5.#sql-918_f727' (errno: 121)
  ERROR 1005 (HY000) at line 104: Can't create table 'otrs5.#sql-918_f727' (errno: 121)
  
  
  root@otrs: su -c "/opt/otrs/scripts/DBUpdate-to-5.pl" -s /bin/bash otrs
  
  Migration started...
  
  Step 1 of 17: Refresh configuration cache...
  If you see warnings about 'Subroutine Load redefined', that's fine, no need to worry!
  done.
  
  Step 2 of 17: Check framework version...done.
  
  Step 3 of 17: Migrate Database Column Types...done.
  
  Step 4 of 17: Migrate charset to UTF-8 on auto_response table...done.
  
  Step 5 of 17: Migrate charset to UTF-8 on notification_event table...done.
  
  Step 6 of 17: Migrate event based notifications to support multiple languages...done.
  
  Step 7 of 17: Migrate notifications to event based notifications...ERROR: OTRS-DBUpdate-to-5.pl-42 Perl: 5.16.3 OS: linux Time: Wed Dec 2 15:38:33 2015
  
  Message: Can't add notification 'Old Ticket new note notification ( Duplicate Name )', notification already exists!
  
  Traceback (17187):
  Module: Kernel::System::NotificationEvent::NotificationAdd Line: 271
  Module: main::_MigrateNotifications Line: 1109
  Module: /opt/otrs//scripts/DBUpdate-to-5.pl Line: 162
  </code></pre>
  
  <p>i am upgrading the "otrs5" database it's the old otrs4 database that i have imported</p>
  
  <pre><code>MariaDB [otrs5]&gt; SHOW DATABASES;
  +--------------------+
  | Database |
  +--------------------+
  | information_schema |
  | mysql |
  | otrs5 |
  | performance_schema |
  | test |
  +--------------------+
  5 rows in set (0.00 sec)
  </code></pre>
  
  <p>it's seems that i have a foreign key error, </p>
  
  <pre><code>MariaDB [(none)]&gt; SHOW ENGINE INNODB STATUS;
  ...
  
  | InnoDB | |
  =====================================
  151203 15:05:28 INNODB MONITOR OUTPUT
  =====================================
  Per second averages calculated from the last 27 seconds
  -----------------
  BACKGROUND THREAD
  -----------------
  srv_master_thread loops: 6410 1_second, 6409 sleeps, 634 10_second, 67 background, 67 flush
  srv_master_thread log flush and writes: 6667
  ----------
  SEMAPHORES
  ----------
  OS WAIT ARRAY INFO: reservation count 72, signal count 72
  Mutex spin waits 3, rounds 90, OS waits 3
  RW-shared spins 86, rounds 2580, OS waits 66
  RW-excl spins 0, rounds 90, OS waits 3
  Spin rounds per wait: 30.00 mutex, 30.00 RW-shared, 90.00 RW-excl
  ------------------------
  LATEST FOREIGN KEY ERROR
  ------------------------
  151203 15:01:12 Error in foreign key constraint creation for table `otrs5`.`#sql-918_f752`.
  A foreign key constraint of name `otrs5`.`FK_cloud_service_config_valid_id_id`
  already exists. (Note that internally InnoDB adds 'databasename'
  in front of the user-defined constraint name.)
  Note that InnoDB's FOREIGN KEY system tables store
  constraint names as case-insensitive, with the
  MySQL standard latin1_swedish_ci collation. If you
  create tables or databases whose names differ only in
  the character case, then collisions in constraint
  names can occur. Workaround: name your constraints
  explicitly with unique names.
  --------
  FILE I/O
  --------
  I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
  I/O thread 1 state: waiting for completed aio requests (log thread)
  I/O thread 2 state: waiting for completed aio requests (read thread)
  I/O thread 3 state: waiting for completed aio requests (read thread)
  I/O thread 4 state: waiting for completed aio requests (read thread)
  I/O thread 5 state: waiting for completed aio requests (read thread)
  I/O thread 6 state: waiting for completed aio requests (write thread)
  I/O thread 7 state: waiting for completed aio requests (write thread)
  I/O thread 8 state: waiting for completed aio requests (write thread)
  I/O thread 9 state: waiting for completed aio requests (write thread)
  Pending normal aio reads: 0 [0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0] ,
  ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
  Pending flushes (fsync) log: 0; buffer pool: 0
  1879 OS file reads, 2600 OS file writes, 767 OS fsyncs
  0.00 reads/s, 0 avg bytes/read, 1.48 writes/s, 0.59 fsyncs/s
  -------------------------------------
  INSERT BUFFER AND ADAPTIVE HASH INDEX
  -------------------------------------
  Ibuf: size 1, free list len 0, seg size 2, 0 merges
  merged operations:
  insert 0, delete mark 0, delete 0
  discarded operations:
  insert 0, delete mark 0, delete 0
  Hash table size 276671, node heap has 3 buffer(s)
  0.11 hash searches/s, 5.15 non-hash searches/s
  ---
  LOG
  ---
  Log sequence number 111668678
  Log flushed up to 111668678
  Last checkpoint at 111668678
  Max checkpoint age 869019772
  Checkpoint age target 841862905
  Modified age 0
  Checkpoint age 0
  0 pending log writes, 0 pending chkp writes
  599 log i/o's done, 0.52 log i/o's/second
  ----------------------
  BUFFER POOL AND MEMORY
  ----------------------
  Total memory allocated 137756672; in additional pool allocated 0
  Total memory allocated by read views 384
  Internal hash tables (constant factor + variable factor)
  Adaptive hash index 2266736 (2213368 + 53368)
  Page hash 139112 (buffer pool 0 only)
  Dictionary cache 1725743 (554768 + 1170975)
  File system 83536 (82672 + 864)
  Lock system 334376 (332872 + 1504)
  Recovery system 0 (0 + 0)
  Dictionary memory allocated 1170975
  Buffer pool size 8191
  Buffer pool size, bytes 134201344
  Free buffers 6261
  Database pages 1927
  Old database pages 727
  Modified db pages 0
  Pending reads 0
  Pending writes: LRU 0, flush list 0, single page 0
  Pages made young 0, not young 0
  0.00 youngs/s, 0.00 non-youngs/s
  Pages read 1866, created 61, written 1909
  0.00 reads/s, 0.00 creates/s, 0.93 writes/s
  Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
  Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
  LRU len: 1927, unzip_LRU len: 0
  I/O sum[0]:cur[0], unzip sum[0]:cur[0]
  --------------
  ROW OPERATIONS
  --------------
  0 queries inside InnoDB, 0 queries in queue
  1 read views open inside InnoDB
  0 transactions active inside InnoDB
  0 out of 1000 descriptors used
  ---OLDEST VIEW---
  Normal read view
  Read view low limit trx n:o 1CBAB
  Read view up limit trx id 1CBAB
  Read view low limit trx id 1CBAB
  Read view individually stored trx ids:
  -----------------
  Main thread process no. 2328, id 140526940509952, state: sleeping
  Number of rows inserted 131, updated 151, deleted 473, read 1837
  0.07 inserts/s, 0.22 updates/s, 0.07 deletes/s, 1.07 reads/s
  ------------
  TRANSACTIONS
  ------------
  Trx id counter 1CBAB
  Purge done for trx's n:o &lt; 1CB9B undo n:o &lt; 0
  History list length 1037
  LIST OF TRANSACTIONS FOR EACH SESSION:
  ---TRANSACTION 1CBA5, not started
  MySQL thread id 63319, OS thread handle 0x7fcefa9b1700, query id 645787 localhost otrs
  ---TRANSACTION 0, not started
  MySQL thread id 63317, OS thread handle 0x7fcefa968700, query id 645794 localhost root
  SHOW ENGINE INNODB STATUS
  ---TRANSACTION 1CB86, not started
  MySQL thread id 63296, OS thread handle 0x7fcefa8d6700, query id 645743 localhost otrs
  ---TRANSACTION 1CBAA, not started
  MySQL thread id 63295, OS thread handle 0x7fcefaa43700, query id 645793 localhost otrs
  ----------------------------
  END OF INNODB MONITOR OUTPUT
  ============================
  ...
  </code></pre>