Thank you for the advice to update to 3.4.0.beta4. Because of the PostgreSQL change to version 15 we need a longer maintenance timeslot. But it makes sense to do the update in the next days to see if this solves our problem.
We were a little bit surprised about the PostgreSQL update. We did the update of our test system to 3.4.0.beta3 a few days earlier and had no problems. When we did the update of the production system the database update was suddenly part of the process. We were not prepared for that and skipped the database update. So we have to do it either together with version 3.4.0.beta4 or as a separate step before.
Is it possible that the skipped database update causes our performance issues? Is there an easy way to check if the database indexes and statistics are correct?