From: Antonin Houska <ah@cybertec.at>
To: Amit Kapila <amit.kapila16@gmail.com>
cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
    Mihail Nikalayeu <mihailnikalayeu@gmail.com>,
    Srinath Reddy Sadipiralla <srinath2133@gmail.com>,
    Matthias van de Meent <boekewurm+postgres@gmail.com>,
    Pg Hackers <pgsql-hackers@lists.postgresql.org>,
    Robert Treat <rob@xzilla.net>
Subject: Re: Adding REPACK [concurrently]
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Comments: In-reply-to Amit Kapila <amit.kapila16@gmail.com>
   message dated "Wed, 01 Apr 2026 15:52:15 +0530."
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Date: Wed, 01 Apr 2026 14:31:21 +0200
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Amit Kapila <amit.kapila16@gmail.com> wrote:

> On Wed, Apr 1, 2026 at 3:13=E2=80=AFPM Antonin Houska <ah@cybertec.at> wr=
ote:
> >

> > Nevertheless, I'm not sure it's a good idea for snapbuild.c to handle s=
pecial
> > cases like REPACK. Instead, I'm thinking if snapbuild.c can safely igno=
re XIDs
> > of backends connected to databases other than the one we're decoding.
> >
>=20
> What if such transactions have made changes in the global catalog?
> Even if that won't matter, I feel such a change would be quite
> fundamental to snapbuild machinery and changing at this point would be
> risky.

I had thought that catalog is usually needed only to retrieve the tuple
descriptor, but regression tests with some Assert() statements prove now th=
at
shared catalogs can be accessed too. So that idea does not seem to be usefu=
l.

--=20
Antonin Houska
Web: https://www.cybertec-postgresql.com