Thought I would let you all know in case you have missed it. A few days ago Postgres support was finally merged into Sonarr dev branch (meaning 4.x version). I have already transitioned to it, so far it runs without issue
You can mostly follow the same instructions as for Radarr from here: https://wiki.servarr.com/radarr/postgres-setup
I used the following temporary docker container to do the conversion (obviously replace stuff you need to):
docker run --rm -v Route\to\sonarr.db:/sonarr.db --network=host dimitri/pgloader pgloader --debug --verbose --with “quote identifiers” --with “data only” “sqlite://sonarr.db” “postgresql://user:pwd@DB-IP/sonarr-main”
When it completed the run, it outputs a kind of table that shows if there were any errors. In my case there were 2 tables (cant remember which ones anymore) that couldn’t be inserted, so I edited those manually afterwards, so it matches the ones in the original DB.
This is very exciting, I’ve felt that SQLite has held back the performance of the *arrs for a long time so I’m excited to see this.
We’ll be able to tell with real comparative data now that both options are available, but I’d be shocked if SQLite itself is the bottleneck, especially in a low concurrency scenario (which is the case for most installations of star apps).