From: Ronan Dunklau <ronan.dunklau@aiven.io>
To: pgsql-bugs <pgsql-bugs@lists.postgresql.org>
Subject: FSM Corruption (was: Could not read block at end of the relation)
Date: Fri, 01 Mar 2024 09:56:51 +0100
Message-ID: <1958255.PYKUYFuaPT@aivenlaptop>
In-Reply-To: <1878547.tdWV9SEqCh@aivenlaptop>
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Le mardi 27 f=E9vrier 2024, 11:34:14 CET Ronan Dunklau a =E9crit :
> I suspected the FSM could be corrupted in some way but taking a look at it
> just after the errors have been triggered, the offending (non
> existing)blocks are just not present in the FSM either.

I think I may have missed something on my first look. On other affected=20
clusters, the FSM is definitely corrupted.  So it looks like we have an FSM=
=20
corruption bug on our hands.

The occurence of this bug happening makes it hard to reproduce,  but it's=20
definitely frequent enough we witnessed it on a dozen PostgreSQL clusters.=
=20

In our case, we need to repair the FSM. The instructions on the wiki do wor=
k,=20
but maybe we should add something like the attached patch (modeled after th=
e=20
same feature in pg_visibility) to make it possible to repair the FSM=20
corruption online. What do you think about it ?

The investigation of the corruption is still ongoing.


Best regards,

=2D-
Ronan Dunklau


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