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  1. MariaDB Server
  2. MDEV-20946

Hard FTWRL deadlock under user level locks

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.4
    • Fix Version/s: 10.4.19
    • Component/s: Locking
    • Labels:
      None

      Description

      CREATE TABLE t1(a INT);
      SELECT GET_LOCK("l1", 0);
       
      connect(con1,localhost,root,,);
      LOCK TABLES t1 WRITE;
       
      connection default;
      sleep 1;
      send FLUSH TABLES WITH READ LOCK;
       
      connection con1;
      sleep 1;
      send SELECT GET_LOCK("l1", 10);
       
      connection default;
      reap;
       
      connection con1;
      reap;
      disconnect con1;
       
      connection default;
      SELECT RELEASE_LOCK("l1");
      UNLOCK TABLES;
      DROP TABLE t1;
      

      After MDEV-5336 FTWRL is designed such that it doesn't expect outer MDL locks being held when it is called. Either release user level locks or forbid FTWRL when they're active.

      BACKUP STAGE will likely be affected by this when it receives fixes for some outstanding deadlocks.

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              Assignee:
              monty Michael Widenius
              Reporter:
              svoj Sergey Vojtovich
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                Updated:
                Resolved:

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