Hi,
I'm in the process of migrating a cluster from 15.3 to 16.2. We have a 'zero downtime' requirement so I'm using logical replication to create the new cluster and then perform the switch in the application.
I have a situation where all but one table have done their initial copy. The remaining table is the largest (of course), and the replication slot that is assigned for the copy (pg_378075177_sync_60067_7343845372910323059) is showing as 'active=false' if I select from pg_replication_slots on the publisher.
I've checked the recent logs for both the publishing cluster and the subscribing cluster but I can't see any replication errors. I guess I could have missed them, but it doesn't seem like anything is being 'retried' like I've seen in the past with replication errors.
I've used this mechanism for zero-downtime upgrades multiple times in the past, and have recently used it to upgrade smaller clusters from 15.x to 16.2 without issue.
The clusters are hosted on AWS RDS, so I have no access to the servers, but if that's the only way to diagnose the issue, I can create a support case.
Does anyone have any suggestions as to where I should look for the issue?
Thanks,
Steve