[Wikidata-bugs] [Maniphest] [Closed] T181401: wikidatawiki_p.wb_items_per_site query is slower than expected on Wiki Replicas

[jcrespo]

jcrespo closed this task as "Invalid". jcrespo added a comment.

The query is unoptimally written- it scans every single wikidata item to return none or a few results. Change it to

SELECT 1 FROM wikidatawiki_p.wb_items_per_site WHERE ips_site_page='Harrington Place, Stellenbosch' AND ips_site_id IN ('frwiki', 'eswiki', ...);

The problem with your query is the !=, mysql (or any BTREE-based database) cannnot handle that efficiently. Use OR or IN instead from a list of explicitly defined wikis.

To get advantage of the indexes the table has. This is not a bug with wikidata or labs- those are currently working as intended.

However-

Feel free to propose additional indexes if you think they can be useful to you and are reasonable proposals- we are open to that with no problem.

TASK DETAIL

https://phabricator.wikimedia.org/T181401

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To: jcrespo
Cc: jcrespo, zhuyifei1999, Legoktm, Dispenser, Aklapper, Giuliamocci, 1978Gage2001, Lahi, aborrero, Gq86, Darkminds3113, GoranSMilovanovic, Chicocvenancio, Jrbranaa, QZanden, Tbscho, LawExplorer, Vali.matei, JJMC89, Volker_E, srodlund, Wong128hk, Wikidata-bugs, aude, GWicke, Gryllida, scfc, Mbch331, Jay8g, Krenair, chasemp

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