Re: Logging parallel worker draught

Benoit Lobréau <benoit.lobreau@dalibo.com>

From: Benoit Lobréau <benoit.lobreau@dalibo.com>
To: Sami Imseih <samimseih@gmail.com>
Cc: Tomas Vondra <tomas@vondra.me>, Guillaume Lelarge <guillaume@lelarge.info>, Alena Rybakina <a.rybakina@postgrespro.ru>, pgsql-hackers <pgsql-hackers@postgresql.org>, "Imseih (AWS), Sami" <simseih@amazon.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Melanie Plageman <melanieplageman@gmail.com>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>
Date: 2025-01-20T15:53:23Z
Lists: pgsql-hackers

Attachments

Here is a new set of patches.

The following changed:

* rebase
* simplify the log message to go back to "launched X parallel workers 
(planned: Y)"
* rename the "failure" configuration item to "shortage".

On 1/3/25 17:24, Sami Imseih wrote:> Maintenance work is usually 
planned, so if queries
> issues by the applications are not launching enough workers, it's
> easy to point the blame on the maintenance activity.

I often work on systems I have no prior knowledge of. Some of these 
systems have external schedulers. Having information in PostgreSQL's 
logs is really useful in such cases.

> Maybe it's better to log parallel maintenance workers separately actually
> if there is a truly good justification for it. As it stands now, even
> pg_stat_database
> does not track maintenance workers. Maybe adding logging could also be part
> of that discussion?

The original patch on pg_stat_database included this information. I 
still think that having a centralized way to get the information is 
important, whether in the logs and/or pg_stat_database (preferably both).

I feel that observability is important, and I don't understand why we 
would want to have the information for only a portion of the 
functionality's usage (even if it's the most important).

-- 
Benoit Lobréau
Consultant
http://dalibo.com