From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: Mahendra Singh Thalor <mahi6run@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Faulty HEAP_XMAX_LOCK_ONLY & HEAP_KEYS_UPDATED hintbit combination
Date: Thu, 4 Feb 2021 14:36:37 -0300
Message-ID: <20210204173637.GA30985@alvherre.pgsql> (raw)
In-Reply-To: <20210204163750.GB22612@nol>
On 2021-Feb-05, Julien Rouhaud wrote:
> Thanks, that's way better, copied in v3. I'm still a bit worried about that
> description though, as that flag isn't consistently set for the FOR UPDATE
> case. Well, to be more precise it's maybe consistently set when the hint bits
> are computed, but in some cases the flag is later cleared, so you won't
> reliably find it in the tuple.
Hmm, that sounds bogus. I think the resetting of the other bits should
be undone afterwards, but I'm not sure that we correctly set
KEYS_UPDATED again after the TOAST business. (What stuff does, from
memory, is to make the tuple look as if it is fully updated, which is
necessary during the TOAST handling; if the bits are not correctly set
transiently, that's okay. But it needs reinstated again later, once the
TOAST stuff is finished).
--
Álvaro Herrera 39°49'30"S 73°17'W
"El número de instalaciones de UNIX se ha elevado a 10,
y se espera que este número aumente" (UPM, 1972)
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, rjuju123@gmail.com, mahi6run@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Faulty HEAP_XMAX_LOCK_ONLY & HEAP_KEYS_UPDATED hintbit combination
In-Reply-To: <20210204173637.GA30985@alvherre.pgsql>
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