Re: Introduce XID age and inactive timeout based replication slot invalidation

Hi,

On Wed, Mar 20, 2024 at 12:48:55AM +0530, Bharath Rupireddy wrote:
> On Mon, Mar 18, 2024 at 3:02 PM Bertrand Drouvot
> <bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
> >
> > > > Hm. Are you suggesting inactive_timeout to be a slot level parameter
> > > > similar to 'failover' property added recently by
> > > > c393308b69d229b664391ac583b9e07418d411b6 and
> > > > 73292404370c9900a96e2bebdc7144f7010339cf?
> > >
> > > Yeah, I have something like that in mind. You can prepare the patch
> > > but it would be good if others involved in this thread can also share
> > > their opinion.
> >
> > I think it makes sense to put the inactive_timeout granularity at the slot
> > level (as the activity could vary a lot say between one slot linked to a
> > subcription and one linked to some plugins). As far max_slot_xid_age I've the
> > feeling that a new GUC is good enough.
>
> Well, here I'm implementing the above idea. The attached v12 patches
> majorly have the following changes:
>

Regarding v12-0004: "Allow setting inactive_timeout in the replication command",
shouldn't we also add an new SQL API say: pg_alter_replication_slot() that would
allow to change the timeout property?

That would allow users to alter this property without the need to make a
replication connection.

But the issue is that it would make it inconsistent with the new inactivetimeout
in the subscription that is added in "v12-0005". But do we need to display
subinactivetimeout in pg_subscription (and even allow it at subscription creation
/ alter) after all? (I've the feeling there is less such a need as compare to
subfailover, subtwophasestate for example).

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com