Currently somewhere this is breaking a wmf wiki as not all wmf wiki's have been updated to the new index due to the fact there was no migration sql patch which there is now https://gerrit.wikimedia.org/r/#/c/344452/
Where to run those changes: all wiki's
When to run those changes: when ever the patches are merged and when the train is run next.
- Schema changes to run:
- CREATE INDEX ar_usertext_timestamp ON archive (ar_user_text,ar_timestamp);
- ALTER TABLE archive DROP INDEX usertext_timestamp;