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  1. MariaDB Server
  2. MDEV-14018

problem of lock on concurent insert (from spider i guees)

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      On concurent insert maybe (3 ~ 4) I got global read lock, look like because spider may consider MyRocksDB like non transactional engine.

      +-----------+-------------------------+---------------+---------------------+--------------+-------------------------+
      | THREAD_ID | LOCK_MODE               | LOCK_DURATION | LOCK_TYPE           | TABLE_SCHEMA | TABLE_NAME              |
      +-----------+-------------------------+---------------+---------------------+--------------+-------------------------+
      |      6828 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6831 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6848 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6847 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6869 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6870 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6885 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6895 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6886 | MDL_INTENTION_EXCLUSIVE | NULL          | Global read lock    |              |                         |
      |      6895 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_int__25    |
      |      6885 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_int        |
      |      3693 | MDL_SHARED_HIGH_PRIO    | NULL          | Table metadata lock | pmacontrol   | status_value_double__18 |
      |      6828 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6831 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6848 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6847 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6869 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6870 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      |      6886 | MDL_SHARED_WRITE        | NULL          | Table metadata lock | pmacontrol   | status_value_double     |
      +-----------+-------------------------+---------------+---------------------+--------------+-------------------------+
      

      on processlist we can see : (the oldest transaction)

      show table status from `pmacontrol` like 'status_value_double__18'; 
      

      Nothing about a lock in RocksDB (tried to see TokuDB and InnoDB too)

      One sting strange I can execute this query without problem :

      show table status from `pmacontrol` like 'status_value_double__18'; 
      

      but not a select on table : status_value_double__18

      in same time i saw on error log :

      sept. 21 16:04:51 aurelien-rdc mysqld[20310]: 2017-09-21 16:04:51 140320728037568 [Note] /usr/sbin/mysqld (mysqld 10.2.8-MariaDB-10.2.8+maria~xenial) starting as process 20310
      sept. 21 16:04:51 aurelien-rdc mysqld[20310]: 2017-09-21 16:04:51 140320728037568 [ERROR] mysqld: Can't lock aria control file '/var/lib/mysql/aria_log_control' for exclusive use, error: 11. Will retry for 30 sec lines 1-18/18 (END) 
      
      

      A ticket for Kentoku I guess =)

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              • Assignee:
                Kentoku Kentoku Shiba
                Reporter:
                Aurelien_LEQUOY Aurélien LEQUOY
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                • Created:
                  Updated: