As part of T51199 I found:
These indexes exist on enwiki, commons etc but they are not on tables.sql:
KEY `log_title_time` (`log_title`(16),`log_timestamp`), KEY `log_title_type_time` (`log_title`(16),`log_type`,`log_timestamp`),
They look to be used, at least they are not being reported as unused on sys.schema_unused_indexes.
The logging table has many drifts from production and tables.sql already T51199: Add index log_type_action, T71127: Discrepancies with logging table on different wikis.
I have created this ticket to have a discussion about those two indexes, my first approach would be to be on the safe side and:
- Add those two indexes to tables.sql (as they are existing on most of the wikis already) as part of this ticket
- Fix the existing drifts (which have bitten us already) (the existing two tickets mentioned above)