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Re: Adding locks statistics

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Jeff Davis <pgsql@j-davis.com>, Greg Sabino Mullane <htamfids@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2026-02-20T16:02:49Z
Lists: pgsql-hackers 
Hi,

On 2026-02-20 06:38:07 +0000, Bertrand Drouvot wrote:
> > If the delay is very
> > short it's probably also not that interesting to track, but I guess that's
> > debatable.
> 
> v6 was introducing timed_waits so that we have:
> 
> waits
> timed_waits
> wait_time
> fastpath_exceeded
> 
> timed_waits and wait_time were incremented together and waits was incremented
> unconditionally. I like the idea of being able to track the numbers of waits
> whatever the value of log_lock_waits (or the new track_lock_timing) is. Also
> one could compare waits vs timed_waits.

How could a user benefit from that split? To me this is pointless number
gathering that wastes resources and confuses users.

Seriously, youre introducing stats left and right, you really need to stop and
first carefully think about what those stats could possibly be useful
for. Before writing a patch implementing the stats.

Greetings,

Andres Freund

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix injection point detach timing problem in TAP test for lock stats

  2. Use single LWLock for lock statistics in pgstats

  3. Add tests for lock statistics, take two

  4. Remove isolation test lock-stats

  5. Avoid including clog.h in proc.h

  6. Don't include storage/lock.h in so many headers

  7. Add support for lock statistics in pgstats

  8. Move some code blocks in lock.c and proc.c

  9. Move declarations related to locktags from lock.h to new locktag.h