Message-ID: <b821da13765cd5a0c948e60cd5cd38856840d021.camel@cybertec.at>
Subject: Re: client_connection_check_interval default value
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Fujii Masao <masao.fujii@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Jeremy Schneider <schneider@ardentperf.com>, Jacob Champion	
 <jacob.champion@enterprisedb.com>, "pgsql-hackers@lists.postgresql.org"	
 <pgsql-hackers@lists.postgresql.org>, Marat Buharov
 <marat.buharov@gmail.com>,  Greg Sabino Mullane	 <htamfids@gmail.com>,
 Thomas Munro <thomas.munro@gmail.com>
Date: Wed, 18 Feb 2026 09:03:48 +0100
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On Wed, 2026-02-18 at 14:30 +0900, Fujii Masao wrote:
> On Fri, Feb 6, 2026 at 9:01=E2=80=AFAM Tom Lane <tgl@sss.pgh.pa.us> wrote=
:
> > > The issue is that backends blocked in ProcSleep() are woken up every
> > > client_connection_check_interval and may emit a "still waiting" messa=
ge
> > > each time if log_lock_waits is enabled. To mitigate this, just one id=
ea is
> > > to add a flag to track whether the "still waiting" message has alread=
y been
> > > emitted during a call to ProcSleep(), and suppress further messages
> > > once it has been logged.
> >=20
> > Independently of what's the default, it seems like it'd be valuable to
> > make that interaction better.=C2=A0 I think it is reasonable to keep on
> > emitting "still waiting" every so often, but we could probably
> > rate-limit that to a lot less than every 2 seconds.
>=20
> Attached is a patch that rate-limits the "still waiting on lock" message
> to at most once every 10s.
>=20
> I chose 10s instead of the suggested 2s, since 2s felt too short. But we =
can
> discuss the appropriate interval and adjust it if needed. The value is
> currently hard-coded, as making it configurable does not seem necessary.

I think that 10 seconds is good.

Yours,
Laurenz Albe