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  1. Percona Server for MySQL
  2. PS-680

LP #1192354: accessing information_schema.partitions causes plans to change

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    Details

    • Type: Bug
    • Status: Done
    • Priority: High
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None

      Description

      **Reported in Launchpad by Sergei Glushchenko last update 11-10-2013 14:26:02

      This is to track upstream bug http://bugs.mysql.com/bug.php?id=69179.
      All credits to Justin Swanhart.

      [9 May 4:22] Justin Swanhart
      Description:
      MySQL 5.6 supposed supports persistent statistics.

      I enabled persistent statistics in my "my.cnf" and I also enabled them with the ALTER TABLE statement. However, in my testing, a read-only workload quickly resets the statistics as evidenced by query plans changes which result in severe performance loss.

      In my testing, the first few batches of test queries will execute in 20 seconds or less with the data in the buffer pool, but then a batch of queries will start taking 80 seconds or more. An examination of the EXPLAIN plan on one of the queries in the batch shows a query plan change.

      Reproduction steps are described in upstream bug report.

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            Reporter:
            lpjirasync lpjirasync (Inactive)
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