Hi,
On Fri, Mar 08, 2024 at 10:42:20PM +0530, Bharath Rupireddy wrote:
> On Wed, Mar 6, 2024 at 4:49 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > You might want to consider its interaction with sync slots on standby.
> > Say, there is no activity on slots in terms of processing the changes
> > for slots. Now, we won't perform sync of such slots on standby showing
> > them inactive as per your new criteria where as same slots could still
> > be valid on primary as the walsender is still active. This may be more
> > of a theoretical point as in running system there will probably be
> > some activity but I think this needs some thougths.
>
> I believe the xmin and catalog_xmin of the sync slots on the standby
> keep advancing depending on the slots on the primary, no? If yes, the
> XID age based invalidation shouldn't be a problem.
>
> I believe there are no walsenders started for the sync slots on the
> standbys, right? If yes, the inactive timeout based invalidation also
> shouldn't be a problem. Because, the inactive timeouts for a slot are
> tracked only for walsenders because they are the ones that typically
> hold replication slots for longer durations and for real replication
> use. We did a similar thing in a recent commit [1].
>
> Is my understanding right? Do you still see any problems with it?
Would that make sense to "simply" discard/prevent those kind of invalidations
for "synced" slot on standby? I mean, do they make sense given the fact that
those slots are not usable until the standby is promoted?
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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