Horton

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

Shlok Kyal <shlok.kyal.oss@gmail.com>

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From: Shlok Kyal <shlok.kyal.oss@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Ashutosh Sharma <ashu.coek88@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-09-24T11:10:40Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rename column slotsync_skip_at to slotsync_last_skip.

  2. Add slotsync_skip_reason column to pg_replication_slots view.

  3. Fix test failure caused by commit 76b78721ca.

  4. Fix a BF failure caused by commit 76b78721ca.

  5. Add slotsync skip statistics.

On Thu, 18 Sept 2025 at 11:31, Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Sep 17, 2025 at 8:19 PM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
> >
> > On Wed, Sep 17, 2025 at 5:14 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > On Wed, Sep 17, 2025 at 4:24 PM Hayato Kuroda (Fujitsu)
> > > <kuroda.hayato@fujitsu.com> wrote:
> > > >
> > > > Dear Shlok,
> > > >
> > > > Thanks for creating the patch. Personally I prefer approach2; approach1 cannot
> > > > indicate the current status of synchronization, it just shows the history.
> > > > I feel approach2 has more information than approach1.
> > > >
> > >
> > > I also think so but Ashutosh thought that it would be hacky. Ashutosh,
> > > did you have an opinion on this matter after seeing the patches?
> > >
> >
> > Yes, I’ve looked into both the patches. Approach 1 seems quite
> > straightforward. In approach 2, we need to pass some additional
> > arguments to update_local_sync_slot and
> > update_and_persist_local_synced_slot, which makes it feel a little
> > less clean compared to approach 1, where we simply add a new function
> > and call it directly.
> >
>
> This is because the approach-1 doesn't show the latest value of
> sync_status. I mean in the latest cycle if the sync is successful, it
> won't update the stats which I am not sure is correct because users
> may want to know the recent status of sync cycle. Otherwise, the patch
> should be almost the same. I think we can even try to write a patch
> for approach-2 without an additional out parameter in some of the
> functions.
>
Hi Amit,

I have written a patch which removes passing this extra parameter to
the functions.
I have attached the latest patch in [1].

[1]: https://www.postgresql.org/message-id/CANhcyEVFZN2Mkjs0QHshKm2_3AkQ0eufjkD12eL2MeuVkPyGbw%40mail.gmail.com

Thanks,
Shlok Kyal