Re: BUG #19029: Replication Slot size keeps increasing while logical subscription works fine

On Sun, Aug 24, 2025 at 3:14 AM PG Bug reporting form
<noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 19029
> Logged by: Thadeus Anand
> Email address: thadeus(at)rmkv(dot)com
> PostgreSQL version: 17.6
> Operating system: Ubuntu 24.04.2
> Description:
>
> We have seven servers distributed geographically. We publish about 62 tables
> through logical replication, with six subscribers. We were hugely affected
> by the memory allocation bug after upgrading to 17.5. We had to suspend the
> replication and resort to manually updating the tables.
>
> So we updated to 17.6 almost immediately. Now the logical replication works
> perfectly, but we notice the replication slot folders increasing in size
> quite dramatically, even when there is no lag found in the subscribers.
>

What do you mean by this? Do you mean that restart_lsn of logical
slots is not moving forward or number of slots are growing in
$PGDATA/pg_replslot or something else? Specifically, I want to know
what do you mean by: 'but we notice the replication slot folders
increasing in size'?

--
With Regards,
Amit Kapila.