Re: [patch] Fix checksum verification in base backups for zero page headers

From: Michael Paquier <michael(at)paquier(dot)xyz>
To: Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru>
Cc: Michael Banck <michael(dot)banck(at)credativ(dot)de>, PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [patch] Fix checksum verification in base backups for zero page headers
Date: 2020-10-26 01:13:15
Message-ID: 20201026011315.GA2973@paquier.xyz
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On Fri, Oct 23, 2020 at 08:00:08AM +0900, Michael Paquier wrote:
> Yeah, we could try to make the logic a bit more complicated like
> that. However, for any code path relying on a page read without any
> locking insurance, we cannot really have a lot of trust in any of the
> fields assigned to the page as this could just be random corruption
> garbage, and the only thing I am ready to trust here a checksum
> mismatch check, because that's the only field on the page that's
> linked to its full contents on the 8k page. This also keeps the code
> simpler.

A small update here. I have extracted the refactored part for
PageIsVerified() and committed it as that's independently useful.
This makes the patch proposed here simpler on HEAD, leading to the
attached.
--
Michael

Attachment Content-Type Size
checksums-zeros-v8.patch text/x-diff 7.6 KB

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