From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: Antonin Houska <ah@cybertec.at>
Cc: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Cc: Robert Treat <rob@xzilla.net>
Subject: Re: Adding REPACK [concurrently]
Date: Mon, 16 Mar 2026 23:03:04 +0100
Message-ID: <202603162202.l2sibdzviih7@alvherre.pgsql> (raw)
In-Reply-To: <CAEze2WiixXk+58DTJ+JX6+q-fuX=TFNc3yTLMrbZh17=sLCY2g@mail.gmail.com>
On 2026-Mar-16, Matthias van de Meent wrote:
> On Mon, 16 Mar 2026 at 21:15, Antonin Houska <ah@cybertec.at> wrote:
> > Anyway (fortunately?), the concurrent use of slots by REPACK is limited
> > because, during the initialization of logical decoding, the backend needs to
> > wait for all the transactions having XID assigned to finish, and these include
> > the already running REPACK commands. See SnapBuildWaitSnapshot() and callers
> > if you're interested in details.
>
> Huh, so would you be able to run more than one Repack Concurrently in
> the same database? ISTM that would not be possible, apart from
> possibly a mechanism comparable to the SAFE_IN_IC flag (to not wait on
> those backends).
Yeah, this sounds kind of bad news ...
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"Los dioses no protegen a los insensatos. Éstos reciben protección de
otros insensatos mejor dotados" (Luis Wu, Mundo Anillo)
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, boekewurm+postgres@gmail.com, ah@cybertec.at, mihailnikalayeu@gmail.com, pgsql-hackers@lists.postgresql.org, rob@xzilla.net
Subject: Re: Adding REPACK [concurrently]
In-Reply-To: <202603162202.l2sibdzviih7@alvherre.pgsql>
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