From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
cc: Matthias van de Meent <boekewurm+postgres@gmail.com>,
        Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@postgresql.org
Subject: Re: v16dev: TRAP: failed Assert("size > SizeOfXLogRecord"),
 File: "xlog.c", Line: 1055, PID: 13564
In-reply-to: <20230417180009.akas7axm6vn5lxma@awork3.anarazel.de>
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Comments: In-reply-to Andres Freund <andres@anarazel.de>
	message dated "Mon, 17 Apr 2023 11:00:09 -0700"
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Date: Mon, 17 Apr 2023 14:26:22 -0400
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Andres Freund <andres@anarazel.de> writes:
> On 2023-04-17 13:50:30 -0400, Tom Lane wrote:
>> So previously, log_newpage_range could only have failed in very
>> unlikely circumstances, whereas now it's not hard to hit when
>> committing a table creation.  I wonder what other bugs may be
>> lurking.

> Oh, interesting. We haven't initialized the extra pages added by
> RelationAddExtraBlocks() (in <=3D 15) for quite a while now, so I'm a bi=
t
> surprised it causes more issues for the VM / FSM. I guess it's that it's=
 quite
> common in real workloads to contend on the extension lock and add extra
> blocks, but not in simple single-threaded tests?

I haven't tried hard to run it to ground, but maybe log_newpage_range
isn't used in that code path?  Seems like we'd have detected this
before now if the case were reachable without any crash involved.

			regards, tom lane