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

Daniil Davydov <3danissimo@gmail.com>

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From: Daniil Davydov <3danissimo@gmail.com>
To: Soumya S Murali <soumyamurali.work@gmail.com>
Cc: Jim Jones <jim.jones@uni-muenster.de>, Tom Lane <tgl@sss.pgh.pa.us>, Stepan Neretin <slpmcf@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2026-04-13T14:18:07Z
Lists: pgsql-hackers 
Hi,

On Mon, Apr 13, 2026 at 7:39 PM Soumya S Murali
<soumyamurali.work@gmail.com> wrote:
>
>
> I tested the v16 patch on a clean tree and verified the behavior
> across multiple execution paths.

Thanks!

> Cross-session access is consistently
> blocked; all attempts result in an error - "relation does not exist"

Hm, our patch should give an error like "cannot access temporary relations of
other sessions". If you see "relation does not exist" I guess you try to access
other session's temp table only by its name. It will not work since postgres
will search this name within the "pg_temp" schema of the current session. You
should explicitly specify other session's temp schema name in order to access
its temp tables. You can find examples in our new test.

Please, let me know if I am wrong and the current patch actually allows
"relation does not exist" error to occur. In this case, it should be fixed.

--
Best regards,
Daniil Davydov

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Prevent access to other sessions' temp tables

  2. Add tests for cross-session temp table access

  3. Doc: use "an SQL" consistently rather than "a SQL"

  4. Modify the relcache to record the temp status of both local and nonlocal