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 <20260205150452.00006167@ardentperf.com> <CAHGQGwHZUmg+r4kMcPYt_Z-txxVX+CJJhfra+qemxKXvAxYbpw@mail.gmail.com>
 <1667818.1770336112@sss.pgh.pa.us>
In-Reply-To: <1667818.1770336112@sss.pgh.pa.us>
From: Fujii Masao <masao.fujii@gmail.com>
Date: Wed, 18 Feb 2026 14:30:22 +0900
Message-ID: <CAHGQGwGw4LhNwOGQT3nbw3uWy8gL94_MB4T39Wfr4_Vgopuovg@mail.gmail.com>
Subject: Re: client_connection_check_interval default value
To: 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>
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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" message
> > each time if log_lock_waits is enabled. To mitigate this, just one idea=
 is
> > to add a flag to track whether the "still waiting" message has already =
been
> > emitted during a call to ProcSleep(), and suppress further messages
> > once it has been logged.
>
> Independently of what's the default, it seems like it'd be valuable to
> make that interaction better.  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.

Attached is a patch that rate-limits the "still waiting on lock" message
to at most once every 10s.

I chose 10s instead of the suggested 2s, since 2s felt too short. But we ca=
n
discuss the appropriate interval and adjust it if needed. The value is
currently hard-coded, as making it configurable does not seem necessary.

Thoughts?

--=20
Fujii Masao

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