From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Alexander Lakhin <exclusion@gmail.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #17255: Server crashes in index_delete_sort_cmp() due to race condition with vacuum
Date: Tue, 9 Nov 2021 16:02:16 +0100
Message-ID: <20211109150216.fgfybn35mwnkeef3@localhost> (raw)
In-Reply-To: <CAH2-Wzka8u1Y+GNP41TQiHjLMP7mYG9h3i+5jq-FzSKgWXBk+Q@mail.gmail.com>
References: <17255-14c0ac58d0f9b583@postgresql.org>
<20211029145532.kfwqwlrdekunwoa2@localhost>
<20211030213948.3i3f7cieqxzhd7kq@alap3.anarazel.de>
<20211031192051.e3r2uxft3bulymrr@localhost>
<08c2445c-c3c9-ba45-18d3-6399707d8306@gmail.com>
<20211108172852.pvsarxoxi54uatch@localhost>
<CAH2-Wzka8u1Y+GNP41TQiHjLMP7mYG9h3i+5jq-FzSKgWXBk+Q@mail.gmail.com>
> On Mon, Nov 08, 2021 at 10:32:39AM -0800, Peter Geoghegan wrote:
> On Mon, Nov 8, 2021 at 9:28 AM Dmitry Dolgov <9erthalion6@gmail.com> wrote:
> > Interesting, I don't think I've observed those errors. In fact after the
> > recent changes (I've compiled here from 39a31056) around assertion logic
> > and index_delete_check_htid now I'm getting another type of crashes
> > using your scripts. This time heap_page_prune_execute stumbles upon a
> > non heap-only tuple trying to update unused line pointers:
>
> It looks like the new heap_page_prune_execute() assertions catch the
> same problem earlier. It's hard to not suspect the code in pruneheap.c
> itself. Whatever else may have happened, the code in pruneheap.c ought
> to not even try to set a non-heap-only tuple item to LP_UNUSED. ISTM
> that it should explicitly look out for and avoid doing that.
>
> Offhand, I wonder if we just need to have an additional check in
> heap_prune_chain(), which is like the existing "If we find a redirect
> somewhere else, stop --- it must not be same chain" handling used for
> LP_REDIRECT items that aren't at the start of a HOT chain:
Yes, adding such condition works in this case, no non-heap-only tuples
were recorded as unused in heap_prune_chain, and nothing else popped up
afterwards. But now after a couple of runs I could also reproduce (at
least partially) what Alexander was talking about:
ERROR: could not open relation with OID 1056321
Not sure yet where is it coming from.
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To: pgsql-bugs@postgresql.org
Cc: 9erthalion6@gmail.com, pg@bowt.ie, exclusion@gmail.com, andres@anarazel.de, boekewurm+postgres@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17255: Server crashes in index_delete_sort_cmp() due to race condition with vacuum
In-Reply-To: <20211109150216.fgfybn35mwnkeef3@localhost>
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