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  1. Moodle
  2. MDL-22098

Broken caching in the grade item classes leads ot O(n) DB queries in the grader report

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Details

    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • 1.9.8
    • 1.9.9
    • Gradebook
    • None
    • MOODLE_19_STABLE
    • MOODLE_19_STABLE

    Description

      I think the diff makes the problem clear.

      Index: lib/grade/grade_item.php
      @@ -871,7 +871,7 @@
            * @return object Grade_category
            */
           function load_item_category() {
      -        if (empty($this->category->id)) {
      +        if (empty($this->item_category->id)) {
                   $this->item_category = $this->get_item_category();
               }
               return $this->item_category;

      This was causing one DB query per category, per student, when showing the grader report, which is very, very bad.

      Andy, adding you as QA assignee, because I believe you are Mr Gradebook these days.

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              timhunt Tim Hunt
              timhunt Tim Hunt
              Nobody Nobody
              Adrian Greeve, Jake Dallimore, Mathew May, Mihail Geshoski, Sujith Haridasan
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              Dates

                Created:
                Updated:
                Resolved:
                8/Jun/10