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  1. MariaDB Server
  2. MDEV-30688

unknown DML blocking reason

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Details

    • Bug
    • Status: Open (View Workflow)
    • Major
    • Resolution: Unresolved
    • 10.6.10
    • 10.6
    • Server
    • None
    • redhat 7 on VMware

    Description

      Hi,

      Our DB is a 3 nodes Galera cluster and all traffic are mainly handled by one DB node only.

      We experienced DB hang today. During real time monitoring, found DML were just querying or killed. We cannot find any reason of the blocking. NO Galera flow control , no row blocking. Show engine innodb status has the transaction but no useful information. You can see below example thread 4932094.

      ProcessList :

      4932094 besdb_user 172.24.150.132:42964 bes_core Killed 660 Update INSERT INTO tb_bes_op_status_upload_hist (ti_upload_toll_domain_id, bi_bes_env_id, i_op_status, vc_create_user_id, vc_update_user_id) VALUES ('9', '3', '0', 'DASTSC1', 'DASTSC1') 660572.384 0 0 0.000 82024 82024 0 1453748629 INSERT INTO tb_bes_op_status_upload_hist (ti_upload_toll_domain_id, bi_bes_env_id, i_op_status, vc_create_user_id, vc_update_user_id) VALUES ('9', '3', '0', 'DASTSC1', 'DASTSC1')

      show engine innodb status:

      ---TRANSACTION 1251810249, ACTIVE 1027 sec inserting
      mysql tables in use 1, locked 1
      1 lock struct(s), heap size 1128, 0 row lock(s)
      MariaDB thread id 4932094, OS thread handle 140036119787264, query id 1453748629 172.24.150.132 besdb_user Update
      INSERT INTO tb_bes_op_status_upload_hist (ti_upload_toll_domain_id, bi_bes_env_id, i_op_status, vc_create_user_id, vc_update_user_id) VALUES ('9', '3', '0', 'DASTSC1', 'DASTSC1')
      TABLE LOCK table `bes_core`.`tb_bes_op_status_upload_hist` trx id 1251810249 lock mode IX

      Metadata lock:
      ------------------------------------------------------------------------------------------------------------+

      THREAD_ID LOCK_MODE LOCK_DURATION LOCK_TYPE TABLE_SCHEMA TABLE_NAME

      ------------------------------------------------------------------------------------------------------------+

      4932094 MDL_BACKUP_TRANS_DML NULL Backup lock    
      4932094 MDL_SHARED_WRITE NULL Table metadata lock bes_core tb_bes_op_status_upload_hist

      ------------------------------------------------------------------------------------------------------------+

      Attached below for reference
      mariadb-error.log - DB error log
      list_mariadb_session_tdffsbe_tdb04.log - process list every 1 min (only 100 each time)
      show-engine-innodb-status.txt - output of "show engine innodb status"
      metadata-lock-info.txt - metadata lock info
      mariadb.cnf - DB option file

      Regards,
      William Wong

      Attachments

        1. mariadb.cnf
          7 kB
        2. show-engine-innodb-status.txt
          1.01 MB
        3. metadata-lock-info.txt
          1.56 MB
        4. list_mariadb_session_tdffsbe_tdb04.log
          6.60 MB
        5. mariadb-error.log
          2.96 MB

        Activity

          People

            janlindstrom Jan Lindström
            frelist William Wong
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            Dates

              Created:
              Updated:

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