Horton

Re: May be BUG. Periodic burst growth of the checkpoint_req counter on replica.

Alexander Korotkov <aekorotkov@gmail.com>

View thread View on postgr.es
From: Alexander Korotkov <aekorotkov@gmail.com>
To: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: "Anton A. Melnikov" <a.melnikov@postgrespro.ru>, Magnus Hagander <magnus@hagander.net>, "Anton A. Melnikov" <aamelnikov@inbox.ru>, Andres Freund <andres@anarazel.de>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-09-18T12:22:57Z
Lists: pgsql-hackers 
On Wed, Sep 18, 2024 at 1:21 PM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
> On 2024/09/17 11:47, Fujii Masao wrote:
> >
> >
> > On 2024/09/16 23:30, Anton A. Melnikov wrote:
> >> +1
> >> This idea seems quite tenable to me.
> >>
> >> There is a small clarification. Now if there were no skipped restartpoints then
> >> restartpoints_done will be equal to restartpoints_timed + restartpoints_req.
> >> Similar for checkpoints.
> >> So i tried to introduce num_done counter for checkpoints in the patch attached.
> >
> > Thanks for the patch! I believe this change is targeted for v18. For v17, however,
> > we should update the description of num_timed in the documentation. Thought?
> > Here's a suggestion:
> >
> > "Number of scheduled checkpoints due to timeout. Note that checkpoints may be
> > skipped if the server has been idle since the last one, and this value counts
> > both completed and skipped checkpoints."
>
> Patch attached.
> Unless there are any objections, I plan to commit this and back-patch it to v17.

I've checked this patch, it looks good to me.

Generally, it looks like I should be in charge for this, given I've
committed previous patch by Anton.  Thank you for reacting here faster
than me.  Please, go ahead with the patch.

------
Regards,
Alexander Korotkov
Supabase

Commits

  1. Improve descriptions of some pg_stat_checkpoints functions in pg_proc.dat.

  2. docs: Enhance the pg_stat_checkpointer view documentation.

  3. Add num_done counter to the pg_stat_checkpointer view.

  4. docs: Improve the description of num_timed column in pg_stat_checkpointer.

  5. Improve documentation for pg_stat_checkpointer fields

  6. Enhance checkpointer restartpoint statistics

  7. Introduce pg_stat_checkpointer