public inbox for [email protected]  

help / color / mirror / Atom feed

From: Pawel Kudzia <[email protected]>
To: Merlin Moncure <[email protected]>
Cc: Vladlen Popolitov <[email protected]>
Cc: [email protected]
Subject: Re: Silent data corruption in PostgreSQL 17 - how to detect it proactively?
Date: Sat, 21 Feb 2026 11:20:07 +0100
Message-ID: <CAJYBUS8UQboD_cNC9qzPSai1iyY4m1eExy1GRnJEJfZX0p4Psw@mail.gmail.com> (raw)
In-Reply-To: <CAHyXU0yCP4+XaYSxX3n5VaR9ym6cejDAvnGYUvqe4CECzLLmcA@mail.gmail.com>
References: <CAJYBUS9T=JCVGkb9yXn5GVYC_g-e5mRi4MFoNHKEZV0keuHHwQ@mail.gmail.com>
	<[email protected]>
	<CAJYBUS9pUjZbqsndbjdHUNugonfQ4DRr_HEn0QkyTXsds0VLMQ@mail.gmail.com>
	<[email protected]>
	<CAHyXU0yCP4+XaYSxX3n5VaR9ym6cejDAvnGYUvqe4CECzLLmcA@mail.gmail.com>

On Tue, Sep 16, 2025 at 6:41 PM Merlin Moncure <[email protected]> wrote:
>
> On Tue, Sep 16, 2025 at 7:25 AM Vladlen Popolitov <[email protected]> wrote:
>>
>> Checksum calculation takes ~0.5% of query time, it is not bottleneck
>> in PostgreSQL.
>
>
> I consider checksums=on to be a mandatory setting.  Often, these types of things are not bugs in postgres itself, but bugs in storage, the underlying operating system, or extensions.  Checksums can and will protect you, and may even bring you close to the thing causing the corruption.  Given that 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 'copy', and for what I believe to be o/s issues, was getting corruption.  Enabling 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!




-- 
regards,
Pawel Kudzia

reply

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: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Silent data corruption in PostgreSQL 17 - how to detect it proactively?
  In-Reply-To: <CAJYBUS8UQboD_cNC9qzPSai1iyY4m1eExy1GRnJEJfZX0p4Psw@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox