When deleting, SELECT ... FOR UPDATE is run not only over page/revision, but also over comment. This is likely to cause more contention, as the same comment would be used for other pages/deletions/etc. We should assume comments are unmutable, and avoid locking them.
More context at T191875#4119830
| Subject | Repo | Branch | Lines +/- | |
|---|---|---|---|---|
| WikiPage: Avoid locking comment and actor tables in doDeleteArticleReal | mediawiki/core | master | +20 -1 |
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Resolved | • Marostegui | T191875 Deletion not working on English Wikipedia | |||
| Resolved | Anomie | T191892 Reduce locking contention on deletion of pages |
I believe this have been happening for some time now, but this incident only made it more real (happening not only for large deletes, but for small ones, too): https://logstash.wikimedia.org/goto/9facbbd99d63704f215285470b16d6f5
Change 425283 had a related patch set uploaded (by Anomie; owner: Anomie):
[mediawiki/core@master] WikiPage: Avoid locking comment and actor tables in doDeleteArticleReal
Change 425283 merged by jenkins-bot:
[mediawiki/core@master] WikiPage: Avoid locking comment and actor tables in doDeleteArticleReal
This should be resolved now, for deployment next week. If you'd like it backported let me know.