Horton

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

Fujii Masao <masao.fujii@oss.nttdata.com>

View thread View on postgr.es
From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: "Anton A. Melnikov" <a.melnikov@postgrespro.ru>, Alexander Korotkov <aekorotkov@gmail.com>
Cc: 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: 2024-09-18T10:21:10Z
Lists: pgsql-hackers

Attachments


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.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

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