We have updated PostgresSQL from version 13.4 to 13.11 and observing 'sorry, too many clients' error very frequently. Connection count is shooting up on performing basic operations and crossing the max_connections value. This has not been observed previously on Postgres v13.4 We need to understand if this issue is caused due to the change in version. Is there any history of known incidents facing this issue with the specific version of PostgreSQL.
I think it is unlikely to be a bug. How did you do the upgrade? Just install the new binaries, then restart the server?
Can you capture plans from the newly slow queries and compare them to plans from the same queries before the upgrade?
