subversive_dev

Done: https://github.com/LemmyNet/lemmy/issues/5555

Good evening Dessalines, I have started looking at the posts query.

The lowest hanging fruit I think would be if we could replace some of the joins with WHERE EXISTS which can have a huge impact on the query time. It seems this is supported in Diesel: https://stackoverflow.com/a/74300447

This is my first time looking at the codebase so I can’t tell yet which joins are purely for filtering (in which case they can be replaced by WHERE EXISTS) and which joins need to be left in because some of their columns end up in the final SELECT

I can’t tell for sure yet but it also looks like this might also be using LIMIT...OFFSET pagination? That can be a real drag on performance but isn’t as easy to fix.

EDIT:

Looking some more, and reading some linked github discussion - I think to really get this out of the performance pits will require some denormalization like a materialized view or manual cache tables populated by triggers. I really like the ranking algorithm but so far I’m finding it difficult to optimize from a query perspective

I should have some time tonight to start looking at this. Thanks for the info!

Does the project maintain a list of known slow queries? This is my favorite type of work

Because some accounts like to spam on certain hashtags, I had the best results with muting an account the second I thought it was annoying. It’s nothing personal, I just don’t want to see their posts on my timeline anymore, which is what mute accomplishes

Oh! I see, you are using a mobile browser, that’s what let me astray

Programmers and designers call that sort of pop-up notification a “toast”. I’m guessing whatever app you are using (there isn’t an official Lemmy app right?) is testing out a 3rd-party library for toasts called Toastify. I’m guessing the dev was so excited to see it working that they forgot to remove the test before publishing