The high-level checklist:
- 1. Merge the first patch for T167246: Refactor "user" & "user_text" fields into "actor" reference table (adding new schemas and code)
- 1.1. Check deployed extensions for needed updates.
- 2. Perform schema change (T188299)
- Interrupt: Remove read-both (gerrit:461440)
- 3. Turn the feature flag to "write both, read old". See if stuff breaks.
- 4. Run the maintenance script(s) to migrate all the old stuff to new stuff.
- s1
- s2
- s3
- s4
- s5
- s6
- s7
- s8
- wikitech
- 5. Turn the feature flag to "write both, read new". See if stuff breaks.
- 5.1. Announce the pending change to wikitech-l@ and cloud@, and give time for people to update.
- 5.2. Make sure all deployed extensions are updated.
- Beta Cluster
- Test wikis
- Group0 wikis
- Group1 wikis
- All wikis
- 6. Turn the feature flag to "new only".
- Beta Cluster
- Test wikis
- Group0 wikis
- Group1 wikis
- All wikis
- 7. Remove old schemas and code
- 7.1. Update WMCS replicas to no longer reference old schemas (T223406).
- 7.2. Write and merge patches to remove $wgActorTableSchemaMigrationStage, supporting code, and old schemas (gerrit:525605)
- 7.3. Submit Schema-change task for WMF production (T233135).
For the cleaning up of revision_actor_temp, see T215466. This and T166733 both block T161671, which in turn is the first step of that task.