Re: CREATE SUBSCRIPTION ... SERVER vs. pg_dump, etc.

On Fri, Jul 31, 2026 at 9:50 AM Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
>
> >
> >
> > * Ensure that none of the commands during restore need a connection.
> > - check_pub_rdt should happen at connection time, and only
> > opportunistically at DDL time if already forming a connection
> >
>
> Amit, this series does not include the check_pub_rdt change to move it
> to the worker.
>

I looked into this problem and agreed that authoritative checking
required for 'rdt' should be done in the worker as even after DDL the
upstream can change. However, I feel it is better to detect the same
at DDL time whenever possible as well as it gives immediate,
synchronous feedback for interactive CREATE/ALTER, whereas a
worker-only failure just lands in the server log and the worker keeps
restarting. Removing it would also mean enabling retain_dead_tuples no
longer validates the publisher at all in the common interactive case.
The only where the DDL-time check is actively harmful is binary
upgrade, where we are just recreating catalog state and must not
connect. So, I would avoid doing that by using IsBinaryUpgrade similar
to how we do in launcher and also add worker-level check as done in
attached.

--
With Regards,
Amit Kapila.