Combine action tables by dullbananas · Pull Request #4459 · LemmyNet/lemmy
github.com
This should cause a huge improvement in query plans, especially for queries that previously reached the from/join collapse limits. For example, getting saved posts might now start with an index sca...

Lemmy currently uses distinct tables like post_like: (post_id, person_id, score) and post_saved. Unfortunately this causes performance issues when we have to join many of these tables to create views.

One suggestion in this PR, is to combine these into a single post_action table, with a lot of optional columns depending on the action. This solution scares me a little, because I’m afraid we might lose data integrity, and many of our constraints with so many optional columns.

Is there a better way of doing this in SQL?

  • @xmunk
    7•4 months ago

    CharGPT has its uses, performance tuning is not (yet) one of them. I think ML in performance tuning will eventually be a huge deal when we can leverage rapid iterations and culling to perform a wide number of small tweaks and compare performance… I haven’t seen a good solution to this yet, it’s a really complex problem, but I think it’s inevitable.