Re: Help diagnosing replication (copy) error

On 3/8/24 13:50, Steve Baldwin wrote:
> 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.

What are the rest of the values in pg_replication_slots?

Is there data in the subscriber side table?

What are the publisher and subscriber configurations?

>
> 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

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com