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Subject: Re: 17.8 standby crashes during WAL replay from 17.5 primary: "could
 not access status of transaction"
From: Andrey Borodin <x4mmm@yandex-team.ru>
In-Reply-To: <349f9c82-3a8b-48ad-8cc4-fe81553793dd@iki.fi>
Date: Sat, 14 Feb 2026 21:18:39 +0500
Cc: Sebastian Webber <sebastian@swebber.me>,
 pgsql-bugs@lists.postgresql.org,
 Andrey Borodin <amborodin@acm.org>,
 =?utf-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>,
 Dmitry Yurichev <dsy.075@yandex.ru>,
 Chao Li <li.evan.chao@gmail.com>,
 Ivan Bykov <i.bykov@modernsys.ru>,
 Kirill Reshke <reshkekirill@gmail.com>
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References: <CACV2tSw3VYS7d27ftO_cs+aF3M54+JwWBbqSGLcKoG9cvyb6EA@mail.gmail.com>
 <349f9c82-3a8b-48ad-8cc4-fe81553793dd@iki.fi>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Archived-At: <https://www.postgresql.org/message-id/FC778C81-C310-4F9B-99EC-920EAF853F8C%40yandex-team.ru>
Precedence: bulk

Ouch...

I remember this place. For some reason I thought endTruncOff is the end =
of offsets. That would make sense here... Now I see it's just a new =
oldest offset.

> On 14 Feb 2026, at 16:42, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>=20
> If we want to play it even more safe -- and I guess that's the right =
thing to do for backpatching -- we could set latest_page_number =
*temporarily* while we do the the truncation, and restore the old value =
afterwards.

As far as I can see, the only relevant usage of last_page_number is:
/*
 * While we are holding the lock, make an important safety check: the
 * current endpoint page must not be eligible for removal.
 */
if (ctl->PagePrecedes(shared->latest_page_number, cutoffPage))
{
	LWLockRelease(shared->ControlLock);
	ereport(LOG,
		(errmsg("could not truncate directory \"%s\": apparent =
wraparound",
		ctl->Dir)));
	return;
}


Perhaps, we also can bump latest_page_number forward?


Best regards, Andrey Borodin.=