Re: Clear padding in PgStat_HashKey keys

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2024-11-04T10:07:37Z
Lists: pgsql-hackers
Hi,

On Mon, Nov 04, 2024 at 06:49:04PM +0900, Michael Paquier wrote:
> On Mon, Nov 04, 2024 at 08:52:04AM +0000, Bertrand Drouvot wrote:
> > Yeah, but not only the relfilenode ones. All kinds were affected as random data
> > was in the padding bytes for all of them.
> 
> A quick test where I add some padding junk in PgStat_HashKey proves
> that you are right.

Thanks for the testing!

> I'm wondering if we should backpatch that,
> actually, down to where it has been introduced.  We are unlikely going
> to change this structure,

Yeah.

> but if we do for the sake of a bug fix,
> which is always a possibility as ABI does not matter much for this
> internal structure, that's potentially trouble waiting ahead.

That's right.

> Thoughts?

hm, yeah I think that it could fall into the "low-risk fixes" category [0] and
that we can opt for backpatch.

[0]: https://www.postgresql.org/support/versioning/

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com



Commits

  1. Clear padding of PgStat_HashKey when handling pgstats entries