Uploaded image for project: 'Moodle'
  1. Moodle
  2. MDL-52801

healthcheck hangs up on a certain set of data: introduce new DML aggregation method for concatenation

    XMLWordPrintable

Details

    Description

      problem_000013 class from admin/tool/health/index.php sends an unoptimal database query which makes N*M scans in the database (N,M - number of rows in

      {question}

      ,

      {question_multianswer}

      accordingly) which is very time-consuming process.

      TO REPRODUCE:
      create 500k records in both tables and try to run
      /admin/tool/health/index.php script

      WHAT EXPECTED:
      linear complexity at least. Execution time < 30 seconds

      WHAT HAPPENED:
      N^2 complexity. Execution time > 900 seconds

      Attachments

        Issue Links

          Activity

            People

              Unassigned Unassigned
              baleevskii Grigory Baleevskiy
              Votes:
              1 Vote for this issue
              Watchers:
              8 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved: