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help / color / mirror / Atom feedFrom: JoongHyuk Shin <sjh910805@gmail.com>
To: Álvaro Herrera <alvherre@kurilemu.de>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Fujii Masao <masao.fujii@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>
Cc: Vitaly Davydov <v.davydov@postgrespro.ru>
Subject: Re: [PATCH] Prevent repeated deadlock-check signals in standby buffer pin waits
Date: Fri, 22 May 2026 17:41:03 +0900
Message-ID: <CACSdjfNFb8KFbnp3=BAJfqXPRTgJiyP34R39ZWhxPy56GsCVLg@mail.gmail.com> (raw)
In-Reply-To: <agt3Aez4a51JC5Ji@alvherre.pgsql>
References: <aecRYWJmfQnuVDBe@paquier.xyz>
<agt3Aez4a51JC5Ji@alvherre.pgsql>
Hello.
Same function, different races, I think.
Vitaly reports a missed wake-up where deadlock_timeout never fires
(spurious SIGALRM from log_startup_progress_interval plus the lazy
setitimer in 09cf1d52).
This patch addresses the opposite,
deadlock_timeout does fire, but LockBufferForCleanup loops back and re-arms
it,
so the signal repeats once per second.
The two fixes do not overlap
(the added ProcWaitForSignal sits inside the deadlock branch that Vitaly's
scenario never reaches).
--
JH Shin
On Wed, May 20, 2026 at 7:15 AM Álvaro Herrera <alvherre@kurilemu.de> wrote:
> Hello,
>
> On 2026-Apr-21, Michael Paquier wrote:
>
> > On Tue, Apr 21, 2026 at 02:42:38PM +0900, Fujii Masao wrote:
> > > Since this change improves recovery-conflict behavior rather than
> fixing a bug,
> > > it doesn't seem to need backpatching and we may need to wait until v20
> > > development opens (probably July) before committing it.
> >
> > Yeah, this one is an improvement, not an actual bug, so let's wait for
> > v20 if worth doing (I did not check it).
>
> Hmm, is this related to
> https://postgr.es/m/44c24dcf-5710-410f-b1b6-d10b315f3d51@postgrespro.ru ?
> In there, Vitaly claims to be reporting a bug that goes back to pg15,
> which contradicts this assessment.
>
> Regards,
>
> --
> Álvaro Herrera Breisgau, Deutschland —
> https://www.EnterpriseDB.com/
> "¿Qué importan los años? Lo que realmente importa es comprobar que
> a fin de cuentas la mejor edad de la vida es estar vivo" (Mafalda)
>
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To: pgsql-hackers@postgresql.org
Cc: sjh910805@gmail.com, alvherre@kurilemu.de, michael@paquier.xyz, masao.fujii@gmail.com, pgsql-hackers@lists.postgresql.org, v.davydov@postgrespro.ru
Subject: Re: [PATCH] Prevent repeated deadlock-check signals in standby buffer pin waits
In-Reply-To: <CACSdjfNFb8KFbnp3=BAJfqXPRTgJiyP34R39ZWhxPy56GsCVLg@mail.gmail.com>
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