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: 2023-12-24T23:38:13Z
Lists: pgsql-hackers
On Sat, Dec 23, 2023 at 12:04 AM Alexander Korotkov
<aekorotkov@gmail.com> wrote:
> 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.

Pushed!

------
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