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Lemmy.world down, probably following the upgrade. A reminder to move to smaller instances for a better experience (files.catbox.moe)
submitted 3 years ago* by to c/fediverse@lemmy.ml
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[–] 0 points 3 years ago (4 children)

What is a SQL trigger and why is it taking down servers? Do you know how to fix it?

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  • [–] 1 point 3 years ago (3 children)

    I think 0.18.3 fixed some of it, but there are likely some more performance issues related to PostgreSQL lurking in Lemmy.

    A TRIGGER in SQL is a logic that executes based on other activity.

    Lemmy uses them so that when you create a new comment or post, it executes code to insert tracking record for votes and comments on a post. One of the things Lemmy does is called site_aggregates, and there was a bug where it was updating the counts for 1500 servers instead of just the one server. That got fixed in 0.18.3

    Deleting accounts in lemmy was causes crashes. I'm not sure if that has been entirely resolved. These things are all kind of hidden in the background of the code, so a lot of developers overlooked that there were problems in them.

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  • [–] 1 point 3 years ago (2 children)

    Isn’t there a logstream they could tap into to have a separate async tally going on instead of doing it synchronously? Probably a lot of things could be delegated to an async job performed when server load allows?

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  • [–] 3 points 3 years ago* (1 child)

    I've had to really adjust my thinking with this project. They want to do things a very particular way and it goes back 4 years, and a lot of the mistakes are just now getting noticed/attention. For example, comments were not deleting on all the servers, I was testing that after comparing server copies of the same communities and found they were not the same. It just didn't seem to have a lot of people spot-checking it for mistakes. I am learn to just "go with the flow" and face that it's more like how musicians would approach design and running a project. Media-focused systems can be that way.

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