Some learning about JOIN filled queries like the SELECT that is used to list post_aggregates table when browsing postings on Lemmy.

https://dba.stackexchange.com/questions/155972/postgres-join-conditions-vs-where-conditions

“Logically, it makes no difference at all whether you place conditions in the join clause of an INNER JOIN or the WHERE clause of the same SELECT. The effect is the same. (Not the case for OUTER JOIN!)”

Learning about join_collapse_limit

  • RoundSparrow @ BTOPM
    1•1 year ago

    I’m studying: LEFT OUTER JOIN “community_person_ban” ON ((“post_aggregates”.“community_id” = “community_person_ban”.“community_id”) AND (“community_person_ban”.“person_id” = “post_aggregates”.“creator_id”))) … and the SELECT field has (“community_person_ban”.“id” IS NOT NULL)

    I’m concerned a ban-happy community ends up having thousands of rows of people they have banned, and every SELECT to list posts has to process that.