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  1. Moodle
  2. MDL-71731

PHPUnit memory usage almost doubled recently (3.10dev)

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      We have started to get some out-of-memory errors in some branches having a good number of unit tests. But it was hard to trace.

      So we tried some "phpunit leak detectors" (a plugin, a listerner...) and, while they reported a good number of tests leaking memory, it was not easy to go checking each:

      https://gist.github.com/stronk7/3632139e3a52d4137a66338c5b005719

      But the final surprise came when it was discovered that 39_STABLE (and earlier) was using "only" ~800 MB to perform complete runs. And MOODLE_310_STABLE (current) and up are the ones requiring ~1800 MB to perform the very same complete runs.

      Initially my thoughts were that, maybe, the upgrade to PHPUnit 8.5 (MDL-67673) could be the culprit, but did run a test before that issue and the memory problem was already there (~1700 MB to run).

      Note that all the runs are with PHPUNIT_LONGTEST set.

      So, at the end, a bisect has been performed between:

      • good: 500c131 - Moodle 3.9.0 release : 886 MB
      • bad: 5903054 - The issue BEFORE PHPUnit 8.5, already wrong: 1700 MB

      And the bisect has ended with:

      0deb19468d0e61c0f3c41fb8d350cd2611fad47e is the first bad commit
      commit 0deb19468d0e61c0f3c41fb8d350cd2611fad47e
      Author: sam marshall <s.marshall@open.ac.uk>
      Date:   Wed May 13 12:11:21 2020 +0100
       
          MDL-68690 Search: Allow Solr to add documents in batches
          
          Adding documents in batches instead of one at a time can make
          indexing using Solr significantly faster.
          
          This adds new API functions for search engines, including
          add_document_batch() to add a batch of documents,
          supports_add_document_batch(), get_batch_max_documents() and
          get_batch_max_content().
       
       search/classes/engine.php                |  97 +++++++++++++++++++--
       search/classes/manager.php               |  36 ++++++--
       search/engine/solr/classes/engine.php    | 100 +++++++++++++++++++++-
       search/engine/solr/tests/engine_test.php | 142 +++++++++++++++++++++++++++++++
       search/upgrade.txt                       |   8 ++
       5 files changed, 367 insertions(+), 16 deletions(-)
      

      To confirm it, I've run PHPUnit tests @ CI:

      So, double confirmation about the issue causing the double memory regression.

      Ciao

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              stronk7 Eloy Lafuente (stronk7)
              stronk7 Eloy Lafuente (stronk7)
              Marina Glancy Marina Glancy
              Andrew Lyons Andrew Lyons
              CiBoT CiBoT
              Amaia Anabitarte, Carlos Escobedo, Ferran Recio, Ilya Tregubov, Sara Arjona (@sarjona), Andrew Lyons, Huong Nguyen, Jun Pataleta, Michael Hawkins, Shamim Rezaie, Simey Lameze
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              Dates

                Created:
                Updated:
                Resolved:
                12/Jul/21

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