Horton

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

Anton A. Melnikov <a.melnikov@postgrespro.ru>

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From: "Anton A. Melnikov" <a.melnikov@postgrespro.ru>
To: Alexander Korotkov <aekorotkov@gmail.com>, "Anton A. Melnikov" <aamelnikov@inbox.ru>
Cc: Andres Freund <andres@anarazel.de>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-12-04T01:49:59Z
Lists: pgsql-hackers

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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.

With the best wishes,

-- 
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

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