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submitted 11 months ago* (last edited 11 months ago) by RoundSparrow@lemmy.ml to c/lemmyperformance@lemmy.ml

Details here: https://github.com/LemmyNet/lemmy/issues/3165

This will VASTLY decrease the server load of I/O for PostgreSQL, as this mistaken code is doing writes of ~1700 rows (each known Lemmy instance in the database) on every single comment & post creation. This creates record-locking issues given it is writes, which are harsh on the system. Once this is fixed, some site operators will be able to downgrade their hardware! ;)

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[-] _Rho_@lemmy.world 38 points 11 months ago

This is fascinating

My biggest takeaway from reading through the GitHub comments though is that it seems like no one actually knows where much of the SQL comes from? As in it's possible that the bug in question is just one manifestation of old, handwritten Postres code that may or may not be optimized (Or even logical?).

I don't mean this in a critical way, as things like this are bound to happen in an open-source, federated world. However, I would think a comprehensive audit of the Lemmy Postgres triggers, queries, etc could potentially save us all from some future headaches.

this post was submitted on 23 Jul 2023
240 points (99.2% liked)

Lemmy Server Performance

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Lemmy Server Performance

lemmy_server uses the Diesel ORM that automatically generates SQL statements. There are serious performance problems in June and July 2023 preventing Lemmy from scaling. Topics include caching, PostgreSQL extensions for troubleshooting, Client/Server Code/SQL Data/server operator apps/sever operator API (performance and storage monitoring), etc.

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