Use stemming in the MySQL fulltext search engine
Summary:
Ref T6740. When we index a document, also save a copy of the stemmed version.
When querying, search the combined corpus for the terms.
(We may need to tune this a bit later since it's possible for literal, quoted terms to match in the stemmed section, but I think this wil rarely cause issues in practice.)
A downside here is that search sort of breaks if you upgrade into this and don't reindex. I wasn't able to find a way to issue the query that remained compatible with older indexes and didn't have awful performance, so my plan is:
- Put this on secure.
- Rebuild the index.
- If things look good after a couple of days, add a way that we can tell people they need to rebuild the search index with a setup warning.
We might get some reports between now and then, but if this is super awful we should know by the end of the weekend.
Test Plan:
WOW AMAZING
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T6740
Differential Revision: https://secure.phabricator.com/D16947