From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
Cc: Francesco Degrassi <francesco.degrassi@optionfactory.net>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: Leader backend hang on IPC/ParallelFinish when LWLock held at parallel query start
Date: Thu, 07 Nov 2024 12:17:21 -0500
Message-ID: <3441950.1730999841@sss.pgh.pa.us> (raw)
In-Reply-To: <20240918050434.13.nmisch@google.com>
References: <CAC-SaSzHUKT=vZJ8MPxYdC_URPfax+yoA1hKTcF4ROz_Q6z0_Q@mail.gmail.com>
<20240918030159.2a.nmisch@google.com>
<1737570.1726633422@sss.pgh.pa.us>
<20240918050434.13.nmisch@google.com>
Noah Misch <noah@leadboat.com> writes:
> On Wed, Sep 18, 2024 at 12:23:42AM -0400, Tom Lane wrote:
>> I do not have much faith in this patch. It assumes that the
>> condition "interrupts can be processed" is the same at plan time and
>> execution time. For plans extracted from the plan cache, there seems
>> little reason to assume that must be true. The proposed test case
>> cannot trigger that (today anyway) because SQL-language functions
>> don't deal in cached plans, but I suspect it could be broken with a
>> test case using a plpgsql function instead.
> Good point. I missed that.
While working on the release notes, I noticed that nothing further
got done about this concern. What do you think of adding a test
somewhere early in executor startup, to the effect of
if (!INTERRUPTS_CAN_BE_PROCESSED())
ereport(ERROR,
(errmsg("cannot start a query with interrupts disabled")));
It's definitely a band-aid, but it seems better than leaving
things at the status quo.
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, noah@leadboat.com, francesco.degrassi@optionfactory.net, pgsql-bugs@lists.postgresql.org
Subject: Re: Leader backend hang on IPC/ParallelFinish when LWLock held at parallel query start
In-Reply-To: <3441950.1730999841@sss.pgh.pa.us>
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