From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Justin Pryzby <pryzby@telsasoft.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: ENOSPC FailedAssertion("!(RefCountErrors == 0)"
Date: Mon, 16 Jul 2018 10:39:26 -0400
Message-ID: <20436.1531751966@sss.pgh.pa.us> (raw)
In-Reply-To: <20180716131337.usestwjviwwocpyz@alap3.anarazel.de>
References: <20180627233939.GA10276@telsasoft.com>
<20180628020432.GB11054@paquier.xyz>
<7317.1531694923@sss.pgh.pa.us>
<20180716131337.usestwjviwwocpyz@alap3.anarazel.de>
Andres Freund <andres@anarazel.de> writes:
> On 2018-07-15 18:48:43 -0400, Tom Lane wrote:
>> So basically, WAL replay hits an error while holding a buffer pin, and
>> nothing is done to release the buffer pin, but AtProcExit_Buffers thinks
>> something should have been done.
> I think there's a few other cases where we hit this. I've seen something
> similar from inside checkpointer / BufferSync(). I'd be surprised if
> bgwriter couldn't be triggered into the same.
Hm, yeah, on reflection it's pretty obvious that those are hazard cases.
> I'm pretty sure that we do *not* force a panic on all nonzero-exit-code
> cases for other subprocesses.
That's my recollection as well -- mostly, we just start a new one.
So I said I didn't want to do extra work on this, but I am looking into
fixing it by having these aux process types run a ResourceOwner that can
be told to clean up any open buffer pins at exit. We could be sure the
coverage is complete by dint of removing the special-case code in
resowner.c that allows buffer pins to be taken with no active resowner.
Then CheckForBufferLeaks can be left as-is, ie something we do only
in assert builds.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, andres@anarazel.de, michael@paquier.xyz, pryzby@telsasoft.com
Subject: Re: ENOSPC FailedAssertion("!(RefCountErrors == 0)"
In-Reply-To: <20436.1531751966@sss.pgh.pa.us>
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