This is a cleanup, there should be no harm in waiting until it can be combined with other changes to the archive table that require depooling replicas. I know of several coming up in the foreseeable future:
- Dropping ar_text and ar_flags (https://gerrit.wikimedia.org/r/c/393929/, currently blocked on T185128)
- A patch to drop ar_comment once the comment table migration is complete.
- A patch to drop ar_user and ar_user_text once the actor table migration is complete.
- A patch for T183487 to drop ar_text_id, ar_content_model, and ar_content_format once MCR migration is complete.
This must not be run until T191307 is resolved. But since I plan to take care of that either this week or next, while I fully expect this to not be started for months, that shouldn't be a problem.
From the checklist at https://wikitech.wikimedia.org/wiki/Schema_changes:
- ALTERs to run: https://gerrit.wikimedia.org/r/c/402932/8/maintenance/archives/patch-ar_rev_id-not-null.sql
- Where to run those changes: all.dblist
- When to run those changes: No time constraint. See details above.
- If the schema change is backwards compatible: Yes.
- If the schema change has been tested already on some of the test/beta wikis: It'll be automatically deployed to Beta Cluster soon enough, if it hasn't already.
- if the data should be made available on the labs replicas and/or dumps: N/A, there is no new data in this change
Schema change progress:
- eqiad progress T191316#4312206
- eqiad progress T191316#4394062
- eqiad progress T191316#4270987
- eqiad progress T191316#4248154
- eqiad progress T191316#4260469
- eqiad progress T191316#4387324
- eqiad progress T191316#4320909