In order to make your issue reports as actionable as possible, please provide the following information, depending on the issue type.

Bug report

When replication slot is lost, connector attempts to restart. If errors.max.retries config isn't set connector will always restart. Debezium postgres task has two postgres connections in normal condition. However when connector's task is restarted due to replication slot's loss, the connections don't close. They stay in idle state (you can see it in pg_stat_activity). When task restart's it fails again due to lost slot and  leaves 2 new connections in idle state. It continues further and finally, debezium connector consumes all  available connections. After that task goes to failed status, but all connections stays in idle status and aren't closed even if  idle_session_timeout is configured.

What Debezium connector do you use and what version?

2.6.2-Final

What is the connector configuration?

What is the captured database version and mode of deployment?

Postgres 16

What behavior do you expect?

Connections of previous task are closed when it restarts

What behavior do you see?

Connections stay in idle status

Do you see the same behaviour using the latest released Debezium version?

Didn't check

Do you have the connector logs, ideally from start till finish?

(You might be asked later to provide DEBUG/TRACE level log)

I'll provide it if required.

How to reproduce the issue using our tutorial deployment?

setup low max slot wal keep size for postgres, disable heartbeat table, execute queries on table of same db, which isn't tracked by debezium. Wait till replication slot gets lost. Observe consuming connections.