Re: How can end users know the cause of LR slot sync delays?

On Mon, Sep 22, 2025 at 3:41 PM Shlok Kyal <shlok(dot)kyal(dot)oss(at)gmail(dot)com> wrote:
>
> On Thu, 18 Sept 2025 at 13:17, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
> >
>
> > In addition to this, should anyone really need to query the skip
> > reason if pg_replication_slots already shows that the slot is synced
> > and not temporary? Ideally, users should check the slot status in
> > pg_replication_slots, and if it indicates the slot is persisted, there
> > seems little value in enquiring pg_stat_replication_slots for the skip
> > reason. That said, it’s important to ensure the information in both
> > views remains consistent.
> >
> I have a doubt. Why don't we want to report the sync skip reason once
> the slots are persisted?
> for the case:
>
> latestFlushPtr = GetStandbyFlushRecPtr(NULL);
> if (remote_slot->confirmed_lsn > latestFlushPtr)
> {
> /*
> * Can get here only if GUC 'synchronized_standby_slots' on the
> * primary server was not configured correctly.
> */
> ereport(AmLogicalSlotSyncWorkerProcess() ? LOG : ERROR,
> errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
> errmsg("skipping slot synchronization because the
> received slot sync"
> " LSN %X/%08X for slot \"%s\" is ahead of the
> standby position %X/%08X",
> LSN_FORMAT_ARGS(remote_slot->confirmed_lsn),
> remote_slot->name,
> LSN_FORMAT_ARGS(latestFlushPtr)));
>
> return false;
> }
>
> Slot sync skip can happen even for persistent slots. So why should we
> avoid displaying the skip reason in such cases?
>

We should display the skip reason even for persistent slots and clear
the same after a successful sync.

--
With Regards,
Amit Kapila.