On Tuesday, August 12, 2025 5:01 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
Hi,
>
> On Tue, Aug 12, 2025 at 2:21 PM Amit Kapila <amit.kapila16@gmail.com>
> wrote:
> >
> > On Tue, Aug 12, 2025 at 2:06 PM shveta malik <shveta.malik@gmail.com>
> wrote:
> > >
> > > 2)
> > > postgres=# create subscription sub2 connection 'dbname=postgres
> > > host=localhost user=shveta port=5433' publication pub2 WITH
> > > (retain_dead_tuples = false, max_conflict_retention_duration=1000);
> > > NOTICE: created replication slot "sub2" on publisher CREATE
> > > SUBSCRIPTION
> > >
> > > Shall we give notice that max_conflict_retention_duration is ignored
> > > as retain_dead_tuples is false.
> > >
> >
> > How about disallowing this combination?
>
> +1 to disallow that.
I think disallowing this case may not suffice, as users could initially set
(retain_dead_tuples=on, max_conflict_retention_duration=100) but later disable
retain_dead_tuples. This would result in the same state as
(retain_dead_tuples=off, max_conflict_retention_duration=100) unless we disallow
disabling rdt in this case as well.
So, do you think we should disallow both cases, or we only disallow setting
max_conflict_retention_duration for disabled retain_dead_tuples and give NOTICE
in another case ?
I personally prefer a consistent behavior, e.g., either we allow both cases and
give NOTICEs, or we disallow both cases. This is because, if the goal here to
prevent potential misconfigurations by users, the scenario where a user disables
retain_dead_tuples might also be considered a similar misconfiguration. So, I'm
a bit concerned that the benefits of imposing a partial restriction may not
outweigh the risk of generating inconsistent behavior. (And I did not see
similar precedent).
What do you think ?
Best Regards,
Hou zj
