Just upgraded to 10.9.0, server didn’t close properly so there were sqlite .db-wal files left besides the jellyfin.db and library.db files which caused an error about the database tables being locked.:

Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 6: 'database table is locked'.

Solved it by running

systemctl stop jellyfin
cd /var/lib/jellyfin/data
sqlite3 jellyfin.db
> .recover
> .quit
sqlite3 library.db
> .recover
> .quit

Now the .db-wal files were gone and I could

systemctl start jellyfin

I did lose a bunch of music metadata, but the advantage of contributing to musicbrainz is that it’s easily recovered :)