From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Julien Rouhaud <rjuju123@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Faulty HEAP_XMAX_LOCK_ONLY & HEAP_KEYS_UPDATED hintbit combination
Date: Sun, 24 Jan 2021 13:01:33 -0300
Message-ID: <20210124160133.GA32557@alvherre.pgsql> (raw)
In-Reply-To: <20210124061758.GA11756@nol>
On 2021-Jan-24, Julien Rouhaud wrote:
> + /*
> + * Do not allow tuples with invalid combinations of hint bits to be placed
> + * on a page. These combinations are detected as corruption by the
> + * contrib/amcheck logic, so if you disable one or both of these
> + * assertions, make corresponding changes there.
> + */
> + Assert(!((tuple->t_data->t_infomask & HEAP_XMAX_LOCK_ONLY) &&
> + (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)));
>
>
> I attach a simple self contained script to reproduce the problem, the last
> UPDATE triggering the Assert.
>
> I'm not really familiar with this part of the code, so it's not exactly clear
> to me if some logic is missing in compute_new_xmax_infomask() /
> heap_prepare_insert(), or if this should actually be an allowed combination of
> hint bit.
Hmm, it's probably a bug in compute_new_xmax_infomask. I don't think
the combination is sensible.
--
Álvaro Herrera 39°49'30"S 73°17'W
"There is evil in the world. There are dark, awful things. Occasionally, we get
a glimpse of them. But there are dark corners; horrors almost impossible to
imagine... even in our worst nightmares." (Van Helsing, Dracula A.D. 1972)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, rjuju123@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Faulty HEAP_XMAX_LOCK_ONLY & HEAP_KEYS_UPDATED hintbit combination
In-Reply-To: <20210124160133.GA32557@alvherre.pgsql>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox