Parser cache

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The parser cache is currently (2011-08-31) backed by MariaDB with hot keys also residing in MediaWiki's main cache (Memcached).

The configuration is in CommonSettings.php (mediawiki-config.git) as part of a MultiWrite wgObjectCaches key.

Current configuration

  • Cache retention period is set to (as of 2021-06-07 - see T282761):
    • 21 days for wiki pages
    • 10 days for talk pages
  • Semi-random tasks from 2021 containing various current knowledge about parser cache: T282761.
  • Grafana: Parser Cache
  • Each data center has its own parser cache; since multi-DC MediaWiki, it is possible for eqiad and codfw to consistently respond with different parser cache contents (can be tested with WikimediaDebug). A purge appears to correctly purge the parser cache in both data centers. Lucas Werkmeister (WMDE) (talk) 14:11, 13 October 2023 (UTC)Reply[reply]


Prior to 2011, the parser cache was solely memcached-based.

In 2011, we introduced the MySQL-based parser cache. See Parser cache expansion and Disk-backed object cache for details of the 2011 project.

In 2020, an additional local on-host Memcached tier was enabled for parser cache (T264604).