The following schema changes should be applied to the revision and archive table in production, at DBA's discretion:
* Drop rev_text_id, rev_content_model, and rev_content_format that MCR obsoleted.
* Drop ar_text_id, ar_content_model, and ar_content_format that MCR obsoleted.
* Replace rev_comment with rev_comment_id.
* Replace rev_user and rev_user_text with rev_actor, plus associated index changes.
The fields that are going to be dropped have been unused for several months now. Code for accessing them has been removed from core. The patch for dropping them in the updater has been merged, see T251343.
The following patch fields should be applied:
** The ALTER TABLES to run: https://gerrit.wikimedia.org/r/c/mediawiki/core/+/552339/15/maintenance/archives/patch-archive-MCR.sql
* https://gerrit.wikimedia.org/r/c/mediawiki/core/+/552339/15/maintenance/archives/patch-revision-actor-comment-MCR.sql
The patches should be applied to all wikis eventually. It may be wise to test them on labs first, then group0, then the rest. Since the changes alter big tables, they will require a master switch, or may even have to wait for a data center switch. DB lists to apply the patch to:
[] all-labs.dblist on the cloud cluster* Where to run those changes: all wikis
[] group0.dblist* When to run those changes: These changes can be applied at any time
[] group1.dblist* If the schema change is backwards compatible: The necessary conversion scripts have long ago been run. The fields that are being dropped have not been created for new installations for a while. The fields that are going to be dropped have been unused for several months now. Code for accessing them has been removed from core
[] group2.dblist
These changes can be applied at any time* If the schema change has been tested already on some of the test/beta wikis. Usually, the necessary conversion scripts have long ago been run.
The fields that are being dropped have not been created for new installations for a while.as a last test, change should be applied to testwiki first: The schema without these fields has been under testing in CI
So* If it involves new columns or tables, the schema without these fields has been under testing in CI.
The following new columns should be made available on labs and dumps:if the data should be made available on the labs replicas: Some work needed on labs views: T238966#6118001
* rev_comment_id** The following new columns should be made available on labs and dumps:
* rev_actor
The columns that are being dropped should already be emulated on labs, and no longer be replicated directly. This should probably be verified.** rev_comment_id
*** rev_actor