Horton

Re: Adding REPACK [concurrently]

Michael Paquier <michael@paquier.xyz>

View thread
From: Michael Paquier <michael@paquier.xyz>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Antonin Houska <ah@cybertec.at>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Fujii Masao <masao.fujii@gmail.com>, Robert Treat <rob@xzilla.net>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-09-01T00:16:42Z
Lists: pgsql-hackers

Commits

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

  1. Improve REPACK (CONCURRENTLY) error messages some more

  2. Add CONCURRENTLY option to REPACK

  3. Make index_concurrently_create_copy more general

  4. Document the 'command' column of pg_stat_progress_repack

  5. Introduce the REPACK command

  6. Split vacuumdb to create vacuuming.c/h

  7. Revert changes to CONCURRENTLY that "sped up" Xmin advance

On Wed, Aug 27, 2025 at 10:22:24AM +0200, Mihail Nikalayeu wrote:
> That worries me - it is not the behaviour someone expects from a
> database by default. At least the warning should be much more visible
> and obvious.
> I think most of user will expect the same guarantees as [CREATE|RE]
> INDEX CONCURRENTLY provides.

Having a unified path for the handling of the waits and the locking
sounds to me like a pretty good argument in favor of a basic
implementation.

In my experience, users do not really care about the time it takes to
complete a operation involving CONCURRENTLY if we allow concurrent
reads and writes in parallel of it.  I have not looked at the proposal
in details, but before trying a more folkloric MVCC approach, relying
on basics that we know have been working for some time seems like a
good and sufficient initial step in terms of handling the waits and
the locks with table AMs (aka heap or something else).

Just my 2c.
--
Michael