[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Michael edited projects, added Wikidata Change Dispatching & Watchlists, wmde-wikidata-tech; removed [DEPRECATED] wdwb-tech. TASK DETAIL https://phabricator.wikimedia.org/T292548 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: Michael Cc:

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

karapayneWMDE added a comment. Change Dispatch Review 2021-10-27 -confirm that the table is not being used, determine if a schema change is needed, then drop the table (maybe) -work falls into the standard process, so no longer needs to be included in the hike scope TASK DETAIL

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Marostegui added a comment. We normally don't track the restarts, but db1171 was restarted 21 days ago, db1104 is way older (around 80 days) and db1126 two days ago, so that's the one we can double check whether the query arrives or not in a few weeks. db1116 is a backup host so we

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a comment. > On those yes, but if you check that, it is indeed used on _some_ of them. So there is (or was) something hitting that index at the time. Yes, but I thought we were mostly interested in those hosts where it was still being used (db1104, db1126,

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Marostegui added a comment. In T292548#7450949 , @Lucas_Werkmeister_WMDE wrote: > Hm, but if I understand the comment at T291086#7364424 correctly, the index was already unused on

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a comment. Hm, but if I understand the comment at T291086#7364424 correctly, the index was already unused on those hosts? TASK DETAIL https://phabricator.wikimedia.org/T292548 EMAIL PREFERENCES

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Marostegui added a comment. I am restarting quite a bunch of s8 (wikidata) hosts as I am upgrading them. Restarted db1101:3318, db1178 today so we can check by the end of the week if you want. (please ping me to do so) TASK DETAIL https://phabricator.wikimedia.org/T292548 EMAIL

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a comment. Alright, thanks. Should we wait until the databases have been restarted naturally (next DC switch?) and then check again if the index is still used? (The index would’ve been used regularly prior to T290367#7347326

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Marostegui added a comment. It gets cleaned up after each restart. TASK DETAIL https://phabricator.wikimedia.org/T292548 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: Marostegui Cc: Marostegui, Lucas_Werkmeister_WMDE, Aklapper, Michael,

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a subscriber: Marostegui. Lucas_Werkmeister_WMDE added a comment. Hm, strange indeed. @Marostegui how far back does the `schema_unused_indexes` data go? Is it possible the index only appeared to be used due to some old queries, or maybe some manual queries we

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Michael added a comment. Mh, but that makes things only more confusing. There is more background information about this in the comments of T291086 and particularly T291086#7364424 seems to

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a comment. Yeah, I don’t think the `wb_changes_change_revision_id` is used for that view. MariaDB [wikidatawiki]> explain select change_id, change_type, change_time, change_object_id, change_revision_id, if(rev_deleted&4 OR

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Lucas_Werkmeister_WMDE added a comment. > See https://gerrit.wikimedia.org/g/operations/puppet/+/79971d5304a5643b56547ffb956296103fa800c1/modules/profile/templates/wmcs/db/wikireplicas/maintain-views.yaml#839 If I understand correctly, this controls the `wikidatawiki_p.wb_changes` view

[Wikidata-bugs] [Maniphest] T292548: Drop index on change_revision_id in wb_changes table

Maintenance_bot added a project: Wikidata. TASK DETAIL https://phabricator.wikimedia.org/T292548 EMAIL PREFERENCES https://phabricator.wikimedia.org/settings/panel/emailpreferences/ To: Maintenance_bot Cc: Aklapper, Michael, karapayneWMDE, Invadibot, maantietaja, Akuckartz, Nandana, Lahi,