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  1. MariaDB Server
  2. MDEV-407

Print EXPLAIN [ANALYZE] in the slow query log

    Details

    • Type: Task
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Fix Version/s: None
    • Component/s: None
    • Labels:
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      Description

      SHOW EXPLAIN allows to produce EXPLAIN during the query execution. We are now able to save it in the slow query log.

      The user interface is as follows:

      "explain" is a new flag in log-slow-verbosity argument:

      [mysqld]
      ...
      log-slow-verbosity=query_plan,explain

      The output is printed into slow query log like this:

      # User@Host: root[root] @ localhost []
      # Thread_id: 2  Schema: j4  QC_hit: No
      # Query_time: 0.000629  Lock_time: 0.000202  Rows_sent: 3  Rows_examined: 3
      # Full_scan: Yes  Full_join: No  Tmp_table: No  Tmp_table_on_disk: No
      # Filesort: No  Filesort_on_disk: No  Merge_passes: 0
      ## <explain>
      ##   id select_type     table   type    possible_keys   key     key_len ref     rows    Extra
      ##   1  SIMPLE  t1      ALL     NULL    NULL    NULL    NULL    3       Using where
      ## </explain>
      SET timestamp=1381828772;
      select * from t1 where a between 1 and 3333;

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              • Assignee:
                psergey Sergei Petrunia
                Reporter:
                psergey Sergei Petrunia
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                • Created:
                  Updated:
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