schema changes to wbc_entity_usage table on test.wikidata, testwiki, and then wikidata
(already done for testwiki and testwikidata)
| Status | Subtype | Assigned | Task | |
|---|---|---|---|---|
| · · · | ||||
| Resolved | None | T95181 add wb_changes_subscription table on test.wikidata and then wikidata | ||
| Invalid | None | T51188 [DO NOT USE] Schema changes for Wikimedia wikis (tracking) [superseded by #Blocked-on-schema-change] | ||
| Resolved | • Springle | T95179 Deploy schema changes to wbc_entity_usage table on wikidatawiki | ||
| · · · |
even if the tables are small on the test wikis, i'm not sure we can just do patchSql.php for this due to replication.
on https://wikitech.wikimedia.org/wiki/MariaDB#Online_Schema_Changes it says "If modifying indexes, or adding new fields that are nullable and/or have a default value, the change can be applied to each slave first and their masters last, using --no-replicate"
is that something we need, even in this case, and therefore need to use osc? is osc_host.sh something we can do ourselves? I am not sure enough without someone walking me through this, so maybe it's best for springle to do?
for wikidata, wbc_entity_usage table already has 255,723 rows, which seems big enough to need osc.
Anything touching wikidatawiki needs to be done online, either with the OSC script (a wrapper for percona toolkit) or slave-by-slave depool/repool. The kind of change described in this ticket can be done using --no-replicate. It should be added to the tracking ticket and scheduled.
testwiki.wbc_entity_usage is tiny, so feel free to go ahead with that on the master. It won't faze replication.
Don't know what test.wikidata refers to...
Did these for testwiki (table has 45 rows) and testwikidata. (only has 5 rows) test2wiki doesn't have the table yet, since we want to keep one of the test wikis like enwiki etc.
@Springle I could probably figure out and handle OSC for wikidatawiki, but think it's better if you apply these changes to wikidatawiki.
the sql patches are in Wikibase Client in php-1.26wmf1/extensions/Wikidata/extensions/Wikibase/client/sql/*
this is becoming more urgent.
we had T98186 due to the schema change not applied and not realizing we still had to code around it.
Done.
Actually, this was fun. Dropping a not-null field across the fleet without causing replag or explosion needs an unusual approach. Will update wikitech and the OSC script for this scenario.