From: Michael Paquier <michael@paquier.xyz>
To: shihao zhong <zhong950419@gmail.com>
Cc: Jim Jones <jim.jones@uni-muenster.de>
Cc: pgsql-hackers <pgsql-hackers@lists.postgresql.org>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Subject: Re: Add a permission check to pg_stat_get_backend_subxact()
Date: Mon, 14 Sep 2026 16:06:04 +0900
Message-ID: <aqec3MF_GDsMdadl@paquier.xyz> (raw)
In-Reply-To: <CAGRkXqRGVNvvkY7a7X=3Bn=WgfLuFZ5iVsBf+t6HSfm2RwVC+g@mail.gmail.com>
References: <CAGRkXqTBZ+zbVuDC8xGEB6Btj61hsui5H5nGqzFBDyOXc=4bjQ@mail.gmail.com>
<ef48668c-cf8e-4f4b-bf39-4b3b9fb9b85a@uni-muenster.de>
<aqOzYr0It5sP7eFF@paquier.xyz>
<c7a0be5d-5328-41dd-a7bf-6b964e9f7a06@uni-muenster.de>
<aqSXMjhwFFzz_zyo@paquier.xyz>
<CAGRkXqRGVNvvkY7a7X=3Bn=WgfLuFZ5iVsBf+t6HSfm2RwVC+g@mail.gmail.com>
On Sat, Sep 12, 2026 at 08:43:28AM -0400, shihao zhong wrote:
> Thanks for committing that, I will not include 0001 in the following emails.
Fixed the subxact_overflow -> subxact_overflowed, as that's
independent.
> 1. The first test block ran as superuser, so the owner branch of
> HAS_PGSTAT_PERMISSIONS() was never exercised: with "userid" forced to
> InvalidOid the test still passed. The block now grants the test role
> membership in the session's role instead. With that, forcing userid
> to InvalidOid fails the test, and removing the checks fails the
> "unrelated role" block.
>
> 2. The doc paragraph above the per-backend table said the functions
> "return NULL", but activity/wait_event return "<insufficient
> privilege>" and the SRFs return no rows. Reworded.
>
> 3. Commit message: noted that processes owned by no role (autovacuum
> workers, WAL writer, ...) are now visible only to superusers and
> pg_read_all_stats, as in pg_stat_activity, and that no backpatch is
> done.
That seems globally sensible, at quick glance. I am also adding
Bertrand Drouvot in CC to comment about this change, as he has worked
on three of these functions.
@Bertrand, what do you think?
--
Michael
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To: pgsql-hackers@postgresql.org
Cc: michael@paquier.xyz, zhong950419@gmail.com, jim.jones@uni-muenster.de, pgsql-hackers@lists.postgresql.org, bertranddrouvot.pg@gmail.com
Subject: Re: Add a permission check to pg_stat_get_backend_subxact()
In-Reply-To: <aqec3MF_GDsMdadl@paquier.xyz>
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