Re: Adding locks statistics

From: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: Michael Paquier <michael(at)paquier(dot)xyz>, Jeff Davis <pgsql(at)j-davis(dot)com>, Greg Sabino Mullane <htamfids(at)gmail(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: Adding locks statistics
Date: 2026-03-18 04:36:04
Message-ID: abortN3ngqMcaBJ7@ip-10-97-1-34.eu-west-3.compute.internal
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Hi,

On Fri, Feb 27, 2026 at 05:14:31AM +0000, Bertrand Drouvot wrote:
> Hi,
>
> On Fri, Feb 20, 2026 at 05:26:37PM +0000, Bertrand Drouvot wrote:
> > Hi,
> >
> > On Fri, Feb 20, 2026 at 11:02:49AM -0500, Andres Freund wrote:
> > > Hi,
> > >
> > > How could a user benefit from that split? To me this is pointless number
> > > gathering that wastes resources and confuses users.
> >
> > I was thinking that could be useful to know the distribution between "long" waits
> > (greater than the deadlock timeout) among all the waits.
> >
> > If the vast majority are long waits that may indicate that the application is
> > misbehaving (as opposed to a tiny percentage of long waits).
> >
> > I was also thinking to bring those stats per-backend (as a next step) and that
> > could also probably be more useful (distribution per host for example, thanks to
> > joining with pg_stat_activity).
>
> As it seems that I'm the only one thinking that this split could be useful, I'm
> removing it in the attached. We can still split later on if we have requests from
> the field.
>
> So, we're back to what we were discussing before the split. As in v7, 0003 is
> adding the new GUC. So that we can see what having a new GUC implies in ProcSleep()
> and we can just get rid of 0003 if we think the GUC is not worth the extra complexity
> (I don't have a strong opinion on it but tempted to think that the extra GUC is
> not worth it).

PFA, a rebase due to fd6ecbfa75ff.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com

Attachment Content-Type Size
v9-0001-Add-lock-statistics.patch text/x-diff 15.5 KB
v9-0002-Add-the-pg_stat_lock-view.patch text/x-diff 29.9 KB
v9-0003-Introduce-a-new-track_lock_timing-GUC.patch text/x-diff 26.6 KB

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