Summary

The WDQS graph split updater has been running without issues for multiple days on Yarn (as a test environment). We will start deploying it in a production environment next week.

What we've accomplished

Improve multilingual zero-results rate

The write up for "Harmonization Post-Reindex Evaluation, Part II" is available on MediaWiki: https://www.mediawiki.org/wiki/User:TJones_(WMF)/Notes/Language_Analyzer_Harmonization_Notes#Harmonization_Post-Reindex_Evaluation,_Part_II

WDQS graph splitting

the updater with the new split graph support is running fine in yarn

Misc

Resolve some itermittent failures in the cirrus browser testing suite that was making CI tedious
Look into the cache hit rate of the cirrus cache of ParserOutputPageProperties. This should be seeing ~66% hit rate but instead is seeing <1%. This induces significant load on the mediawiki api clusters. Have added metrics and will re-review after deployment. Probably also add some alerting once fixed.
Provide a potential fix for tracking search satisfaction events (frontend/UI) - https://phabricator.wikimedia.org/T286814
Completion suggester can promote a bad build - https://phabricator.wikimedia.org/T363521