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

Alexander Korotkov <aekorotkov@gmail.com>

From: Alexander Korotkov <aekorotkov@gmail.com>
To: "Anton A. Melnikov" <a.melnikov@postgrespro.ru>
Cc: "Anton A. Melnikov" <aamelnikov@inbox.ru>, Andres Freund <andres@anarazel.de>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-12-22T22:04:12Z
Lists: pgsql-hackers

Attachments

Hi, Anton!

On Mon, Dec 4, 2023 at 3:50 AM Anton A. Melnikov <a.melnikov@postgrespro.ru>
wrote:

> Thanks for remarks!
>
> On 28.11.2023 21:34, Alexander Korotkov wrote:
> > After examining the second patch
> > ("v2-0001-Add-restartpoint-stats.patch"), it appears that adding
> > additional statistics as outlined in the patch is the most suitable
> > approach to address the concerns raised. This solution provides more
> > visibility into the system's behavior without altering its core
> > mechanics.
>
> Agreed. I left only this variant of the patch and rework it due to commit
> 96f05261.
> So the new counters is in the pg_stat_checkpointer view now.
> Please see the v3-0001-add-restartpoints-stats.patch attached.
>
>
> > However, it's essential that this additional functionality
> > is accompanied by comprehensive documentation to ensure clear
> > understanding and ease of use by the PostgreSQL community.
> >
> > Please consider expanding the documentation to include detailed
> > explanations of the new statistics and their implications in various
> > scenarios.
>
> In the separate v3-0002-doc-for-restartpoints-stats.patch i added the
> definitions
> of the new counters into the "28.2.15. pg_stat_checkpointer" section
> and explanation of them with examples into the "30.5.WAL Configuration"
> one.
>
> Would be glad for any comments and and concerns.
>

I made some grammar corrections to the docs and have written the commit
message.

I think this patch now looks good.  I'm going to push this if there are no
objections.

------
Regards,
Alexander Korotkov

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