Re: Introduce XID age based replication slot invalidation

On Thu, Aug 13, 2026 at 5:32 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> On Tue, Aug 11, 2026 at 7:00 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> > so is it okay to keep the same behaviour
> > for both max_slot_xid_age and idle_replication_slot_timeout w.r.t
> > synced slots? I am not sure if this is a real risk or just a
> > theoretical possibility but wanted to bring it to your attention so
> > that we can consider it.
>
> I believe this can happen in practice (as explained above). IMHO, XID
> age based slot invalidation must invalidate the synced slot on the
> standby (just like other invalidations except the idle-timeout based)
> if its catalog_xmin is aged and blocking vacuum on the primary.
>

Fair enough, then let's invalidate synced slots as well on standby due
to xid_age but I think it is better to let users build some alerting
system before these slots get invalidated. We can add a column similar
to wal_status in pg_replication_slots which could help users to
indicate that the particular slot is in danger of invalidation.
Additionally, for synced slots, we could add a LOG/WARNING when they
are nearing invalidation as there are no direct consumers for the
same.

--
With Regards,
Amit Kapila.