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  1. Moodle
  2. MDL-46826

forum_discussions requires index on course field

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    • MOODLE_26_STABLE, MOODLE_27_STABLE, MOODLE_28_STABLE
    • MOODLE_26_STABLE, MOODLE_27_STABLE
    • wip-MDL-46826-master
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      repeat testing from MDL-31089, you can limit it to test 2 and test 6 only (group and no-group modes)
      master only: verify upgrade to forum version 20140815 works and the index on forum_discussion (course) is created.

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      repeat testing from MDL-31089 , you can limit it to test 2 and test 6 only (group and no-group modes) master only: verify upgrade to forum version 20140815 works and the index on forum_discussion (course) is created.

    Description

      Occasionally, queries pop up which use forum_discussions.course as the filter condition, and join forum_posts and friends to fetch some data.

      This does not work very well as there is no index on the course field, so it results in quite poor queries.

      The latest case seems to be MDL-31089 which has made forum_print_overview a very serious bottleneck, found when testing 2.5 vs 2.7 performance.

      An index should be added to the course field to prevent these problems.

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              marina Marina Glancy
              tlevi Tony Levi
              Ankit Agarwal Ankit Agarwal
              Eloy Lafuente (stronk7) Eloy Lafuente (stronk7)
              Andrew Lyons Andrew Lyons
              Amaia Anabitarte, Carlos Escobedo, Ferran Recio, Ilya Tregubov, Laurent David, Raquel Ortega, Sara Arjona (@sarjona), Andrew Lyons, Huong Nguyen, Jun Pataleta, Michael Hawkins, Shamim Rezaie, Simey Lameze, Stevani Andolo, Matteo Scaramuccia, Andrew Lyons, Huong Nguyen, Jun Pataleta, Michael Hawkins, Shamim Rezaie, Simey Lameze, Stevani Andolo
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              Dates

                Created:
                Updated:
                Resolved:
                8/Sep/14