Re: Fix bug with accessing to temporary tables of other sessions

On Fri, May 8, 2026 at 9:19 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> On Thu, May 07, 2026 at 11:04:16AM +0300, Alexander Korotkov wrote:
> > Let me do a quick summary:
> > * Our buffer manager is not capable for reading temp tables of other sessions.
> > * This was covered by explicit checks, but broken since b7b0f3f27241
> > introduced alternative code path for reading tables.
> > * This doesn't apply to DROP TABLE. DROP TABLE is a conscious
> > exclusion and the only operation we can do correctly for other
> > session' temp tables. There is an explicit exclusion in the code to
> > skip the attempt to cleanup buffers of other session' temp tables.
> > * This patchset consists of tests (0001) for various operations with
> > other session's temp tables including buggy behavior, and the fix
> > (0002) including changes for tests.
> >
> > Thus, I don't see the reason why this shouldn't be committed and
> > backpatched to PG17 (first release containing b7b0f3f27241).
> > Opinions? Michael?
>
> Hmm. I don't have any counter-arguments against a backpatch based on
> your argument related to b7b0f3f27241. Thanks for reorganizing the
> patch set so as the tests happen first, and the changes in the code
> become second.
>
> If you wish me to look at this patch set in details, I may be able to
> do so around the beginning of next week. I'm not sure that there is a
> strong urgency in tackling this issue for this minor release, this
> could wait a bit more..

Absolutely, no urgency to include it into this minor release as I
already agreed [1]. You're very welcome if you could take a look in
the beginning of the next week.

Links.
1. https://www.postgresql.org/message-id/CAPpHfdsEr6RF-SkzVGD6PzFusENbpNPxKnRY7iQQ%3DcZQYJia6w%40mail.gmail.com

------
Regards,
Alexander Korotkov
Supabase