Since the MCR refactor of the Mediawiki database schema has been progressing
(
https://phabricator.wikimedia.org/T166733
<https://phabricator.wikimedia.org/T166732> and many other tickets), one of the last
steps is dropping the columns from the wiki replica schema.
The column drops are being tracked and are explained well here
https://phabricator.wikimedia.org/T212972
<https://phabricator.wikimedia.org/T212972>, and currently the change is ready to be
applied. It is already applied to two wikis (eswiki and huwiki since there was a column
problem that needed fixing). The tables with names such as <tablename>_compat will
retain a similar structure if that is needed for refactoring.
From the ticket, this is a summary of what is changing, organized by table name:
archive: Remove ar_comment
archive_userindex: Remove ar_comment
filearchive:
Remove fa_deleted_reason
Remove fa_description
filearchive_userindex:
Remove fa_deleted_reason
Remove fa_description
image: Remove img_description
ipblocks: Remove ipb_reason.
ipblocks_ipindex: Remove ipb_reason.
logging: Remove log_comment.
logging_logindex: Remove log_comment.
logging_userindex: Remove log_comment.
oldimage: Remove oi_description
oldimage_userindex: Remove oi_description
recentchanges: Remove rc_comment.
recentchanges_userindex: Remove rc_comment.
revision: Remove rev_comment.
revision_userindex: Remove rev_comment.
The changes to the _compat tables should not affect anything.
We will deploy the change early next week (Tuesday - 3/12/2019). In most cases, if a
table isn’t working for your tool or app anymore because of the change, you can switch to
a table named $tablename_compat and it will appear to have the same schema, but it is
recommended that comment references use a join to the new comment table on a “comment_id”
field instead where possible.
Brooke Storm
Operations Engineer
Wikimedia Cloud Services
bstorm(a)wikimedia.org <mailto:bstorm@wikimedia.org>
IRC: bstorm_