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:
[] s1
** [x] codfw
** [] eqiad progress T191316#4275245 (only primary master pending, but it will be failed over the 18th July - so it will get done that day T197069)
[] s2
** [x] codfw
** [] eqiad progress T191316#4312206
[] s3
** [] codfw
** [] eqiad
[] s4
** [x] codfw
** [x] eqiad progress T191316#4270987
[] s5
** [x] codfw
** [x] eqiad progress T191316#4248154
[] s6
** [x] codfw
** [x] eqiad progress T191316#4260469
[] s7
** [] codfw
** [] eqiad
[] s8
** [x] codfw
** [] eqiad