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  1. MariaDB Server
  2. MDEV-8364

wsrep_dirty_reads not possible with wsrep_sync_wait (deadlock)

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Minor
    • Resolution: Won't Fix
    • 10.0.17-galera
    • N/A
    • Galera
    • None

    Description

      1. Three node galera cluster, with wsrep_sync_wait=1 in /etc/my.cnf
      2. Kill two of three nodes
      3. Connect to last node, try to enable dirty reads and select data from it. You get a lock wait timeout exception (1205). SET wsrep_sync_wait=0 gets you halfway but you still cannot access table data.

      Server version: 10.0.17-MariaDB-wsrep-log
       
      Copyright (c) 2000, 2015, Oracle, MariaDB Corporation Ab and others.
       
      Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
       
      MariaDB [(none)]> select 1;
      ERROR 1047 (08S01): WSREP has not yet prepared node for application use
      MariaDB [(none)]> set wsrep_dirty_reads=1;
      Query OK, 0 rows affected (0.00 sec)
       
      MariaDB [(none)]> select 1;
      ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
      MariaDB [(none)]> set wsrep_sync_wait=0;
      Query OK, 0 rows affected (0.00 sec)
       
      MariaDB [(none)]> select 1;
      +---+
      | 1 |
      +---+
      | 1 |
      +---+
      1 row in set (0.00 sec)
       
      MariaDB [(none)]> use mysql;
      ERROR 1047 (08S01): WSREP has not yet prepared node for application use
      MariaDB [(none)]> select @@global.wsrep_sync_wait;
      +--------------------------+
      | @@global.wsrep_sync_wait |
      +--------------------------+
      |                        1 |
      +--------------------------+
      1 row in set (0.00 sec)
       
      MariaDB [(none)]> set @@global.wsrep_sync_wait=0;
      Query OK, 0 rows affected (0.00 sec)
       
      MariaDB [(none)]> use mysql;
      ERROR 1047 (08S01): WSREP has not yet prepared node for application use
       

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            nirbhay_c Nirbhay Choubey (Inactive)
            rrva Ragnar Rova
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            Dates

              Created:
              Updated:
              Resolved:

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