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  1. MariaDB Server
  2. MDEV-23586

Mariabackup: GTID saved for replication in 10.4.14 is wrong

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      It appears that the fix for https://jira.mariadb.org/browse/MDEV-21953 has introduced a serious regression and now any backup taken with MariaDB server 10.4.14 and above saves the wrong GTID.

      To reproduce, take a mariabackup from a 10.4.14 instance, then notice how the reported position does refer to a GTID which is not proper. In the example below, the PIT corresponds to position 25035029, but the reported GTID 0-1-18691 is wrong and if used, yields several duplicate keys errors. In fact the correct GTID for that position would be 0-1-18699 as reported by BINLOG_GTID_POS() function.

      This wrong GTID is saved to the xtrabackup_slave_info and since the position is no longer saved there (WHY???) the resulting backup does not carry a valid PIT information anymore.
      This is hitting a customer of ours and makes all backups inconsistent due to wrong PIT info, hence the critical priority.

      Thanks to Andrea Ponzo who found and verified this issue.

      Workaround: downgrade server to 10.4.13

      [00] 2020-08-26 12:25:52 Backup created in directory '/root/backup/andre2/xtrabackup_backupfiles/'
      [00] 2020-08-26 12:25:52 MySQL binlog position: filename 'm2-bin.000007', position '25035029', GTID of the last change '0-1-18691'
      [00] 2020-08-26 12:25:52 MySQL slave binlog position: master host '192.168.56.101', gtid_slave_pos 0-1-18691
      [00] 2020-08-26 12:25:52 Streaming backup-my.cnf
      [00] 2020-08-26 12:25:52         ...done
      [00] 2020-08-26 12:25:52 Streaming xtrabackup_info
      [00] 2020-08-26 12:25:52         ...done
      [00] 2020-08-26 12:25:52 Redo log (from LSN 29523906 to 31884588) was copied.
      [00] 2020-08-26 12:25:52 completed OK!
      prepare
      2020-08-26 12:26:53 0 [Note] InnoDB: Starting crash recovery from checkpoint LSN=30269374
      2020-08-26 12:26:53 0 [Note] InnoDB: Starting final batch to recover 286 pages from redo log.
      2020-08-26 12:26:53 0 [Note] InnoDB: Last binlog file './m2-bin.000007', position 25035029
      [00] 2020-08-26 12:26:54 Last binlog file ./m2-bin.000007, position 25035029
      [00] 2020-08-26 12:26:54 completed OK!
      MariaDB [test]> SELECT BINLOG_GTID_POS("m2-bin.000007",25035029 );
      +--------------------------------------------+
      | BINLOG_GTID_POS("m2-bin.000007",25035029 ) |
      +--------------------------------------------+
      | 0-1-18699                                  |
      +--------------------------------------------+
      1 row in set (0.133 sec)
      

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              Assignee:
              monty Michael Widenius
              Reporter:
              rpizzi Rick Pizzi
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                Updated:
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