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From: Pawel Kudzia <kudzia@gmail.com>
Date: Sat, 21 Feb 2026 11:20:07 +0100
Message-ID: <CAJYBUS8UQboD_cNC9qzPSai1iyY4m1eExy1GRnJEJfZX0p4Psw@mail.gmail.com>
Subject: Re: Silent data corruption in PostgreSQL 17 - how to detect it proactively?
To: Merlin Moncure <mmoncure@gmail.com>
Cc: Vladlen Popolitov <v.popolitov@postgrespro.ru>, pgsql-general@lists.postgresql.org
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On Tue, Sep 16, 2025 at 6:41=E2=80=AFPM Merlin Moncure <mmoncure@gmail.com>=
 wrote:
>
> On Tue, Sep 16, 2025 at 7:25=E2=80=AFAM Vladlen Popolitov <v.popolitov@po=
stgrespro.ru> wrote:
>>
>> Checksum calculation takes ~0.5% of query time, it is not bottleneck
>> in PostgreSQL.
>
>
> I consider checksums=3Don to be a mandatory setting.  Often, these types =
of things are not bugs in postgres itself, but bugs in storage, the underly=
ing operating system, or extensions.  Checksums can and will protect you, a=
nd may even bring you close to the thing causing the corruption.  Given tha=
t your replica is ok, this very much smells like a similar type of issue.
>
> In a prior case, I was using pl/sh to load data to the database with 'cop=
y', and for what I believe to be o/s issues, was getting corruption.  Enabl=
ing checksums completely addressed the source of the damage.  Turn them on!
>


i'd like to add a note that might help others - at the end - it was
not PostgreSQL, but a bug in underlying KVM when snapshots were
active. it hit others as well and at the time of writing is not
resolved yet - https://gitlab.com/qemu-project/qemu/-/issues/3273

thanks a lot for help and suggestions!


--=20
regards,
Pawel Kudzia