From the checklist at https://wikitech.wikimedia.org/wiki/Schema_changes:
# **ALTERs to run:** https://gerrit.wikimedia.org/r/#/c/380669/48/maintenance/archives/patch-actor-table.sql, minus the changes to the `image` table that are already being done per T187089#3966227
# **Where to run those changes:** all.dblist
# **When to run those changes:** No time constraint.
# **If the schema change is backwards compatible:** Yes. The new columns and tables won't be used until a feature flag is enabled.
# **If the schema change has been tested already on some of the test/beta wikis:** It has been auto-deployed to Beta. I haven't heard that it broke anything.
# **if the data should be made available on the labs replicas and/or dumps:** Treatment of replicas and dumps are the same.
* All columns in the `actor` table can be made available without restriction. Rows must only be available if (1) `actor_user` refers to a visible row in the `user` table or (2) the row is publicly referenced from one of the _actor columns being added in this patch. Extensions converted to have _actor columns will eventually need to be added to that list. Note: From the MediaWiki side, this table should receive manly INSERTs, no UPDATEs, and DELETEs only due to potential maintenance. Also note {T91706}.
* All columns in `revision_actor_temp` can be made available without restriction. Rows must only be available if the corresponding `revision` table row exists (join on `revactor_rev = rev_id`) and has `(rev_deleted & 4) = 0`. Note: From the MediaWiki side, this table should receive INSERTs and DELETEs but no UPDATEs.
* All the _actor columns added to existing tables should be available under the same conditions as the corresponding _user or _user_text columns. These seem to be:
** archive.ar_actor: Available when `(ar_deleted & 4) = 0`.
** ipblocks.ipb_by_actor: Always available (whenever the row itself is).
** image.img_actor: Always available.
** oldimage.oi_actor: Available when `(oi_deleted & 4) = 0`.
** filearchive.fa_actor: Available when `(fa_deleted & 4) = 0`.
** recentchanges.rc_actor: Available when `(rc_deleted & 4) = 0`.
** logging.log_actor: Available when `(log_deleted & 4) = 0`.
Schema change progress:
[] s1
** [] codfw
** [] eqiad
[] s2
** [x] codfw
** [x] eqiad progress T188299#4160112
[] s3
** [x] codfw
** [x] eqiad progress T188299#4212820
[] s4
** [x] codfw
** [x] eqiad progress T188299#4181128
[] s5
** [x] codfw
** [x] eqiad progress T188299#4139168
[] s6
** [x] codfw
** [x] eqiad progress T188299#4149629
[] s7
** [x] codfw
** [x] eqiad progress T188299#4204535
[] s8
** [x] codfw
** [x] eqiad progress T188299#4222209