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Re: Adding REPACK [concurrently]

Mahendra Singh Thalor <mahi6run@gmail.com>

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From: Mahendra Singh Thalor <mahi6run@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Robert Treat <rob@xzilla.net>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Antonin Houska <ah@cybertec.at>, Mihail Nikalayeu <mihailnikalayeu@gmail.com>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-03-16T17:55:22Z
Lists: pgsql-hackers 
On Mon, 16 Mar 2026 at 21:33, Alvaro Herrera <alvherre@alvh.no-ip.org>
wrote:
>
> On 2026-Mar-16, Robert Treat wrote:
>
> > I'm never excited about adding GUCs, but at first thought this seems
> > like a decent work-around; most people are unlikely to run multiple
> > repack concurrently's, but they can if needed. (I think the most
> > likely use case is on clusters using the "database per customer"
> > pattern, but if we have the guc, people will have a means to deal with
> > it).
>
> I wonder if, longer term, it would make sense to do away with the
> max_replication_slots GUC (and this new one) altogether, and use dynamic
> shared memory for slots instead.  There's of course always the danger
> that people would accumulate arbitrary numbers of slots since they would
> never be forced to check.  But that may be a lesser problem than having
> to gauge these GUCs with any care.
>
> --
> Álvaro Herrera               48°01'N 7°57'E  —
https://www.EnterpriseDB.com/
> "You're _really_ hosed if the person doing the hiring doesn't understand
> relational systems: you end up with a whole raft of programmers, none of
> whom has had a Date with the clue stick."              (Andrew Sullivan)
> https://postgr.es/m/20050809113420.GD2768@phlogiston.dyndns.org
>
>

Hi all,
I was reading this thread and was doing some tests.

postgres=# create table test1(a int);
CREATE TABLE
postgres=# create table test2(a int);
CREATE TABLE
postgres=# *vacuum full test1 , test2;*
VACUUM
postgres=# repack test1;
REPACK
postgres=# repack test2;
REPACK
postgres=#* repack test1, test2;*
ERROR:  syntax error at or near ","
LINE 1: repack test1, test2;
                    ^

I was not expecting any error but maybe I am missing something (some patch
needs to be applied to test this query?).

Thanks and Regards
Mahendra

Commits

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

  1. Allow old WAL recycling during REPACK CONCURRENTLY

  2. Advance restart_lsn more eagerly in LogicalConfirmReceivedLocation

  3. Remove unnecessary signal handler change

  4. Improve REPACK (CONCURRENTLY) error messages some more

  5. Revert "Allow logical replication snapshots to be database-specific"

  6. Move REPACK (CONCURRENTLY) test out of stock regression tests

  7. REPACK: do not require REPLICATION or LOGIN

  8. Add missing initialization

  9. Simplify declaration of memcpy target

  10. Reserve replication slots specifically for REPACK

  11. doc: Add an example of REPACK (CONCURRENTLY)

  12. Allow logical replication snapshots to be database-specific

  13. Avoid different-size pointer-to-integer cast

  14. Fix valgrind failure

  15. Add CONCURRENTLY option to REPACK

  16. Rename cluster.c to repack.c (and corresponding .h)

  17. Allow index_create to suppress index_build progress reporting

  18. Make index_concurrently_create_copy more general

  19. Document the 'command' column of pg_stat_progress_repack

  20. Introduce the REPACK command

  21. Toggle logical decoding dynamically based on logical slot presence.

  22. Split vacuumdb to create vacuuming.c/h

  23. Remove ReorderBufferTupleBuf structure.

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

  25. VACUUM: ignore indexing operations with CONCURRENTLY