Re: Adding REPACK [concurrently]

Antonin Houska <ah@cybertec.at>

From: Antonin Houska <ah@cybertec.at>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Srinath Reddy Sadipiralla <srinath2133@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Mihail Nikalayeu <mihailnikalayeu@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Pg Hackers <pgsql-hackers@lists.postgresql.org>, Robert Treat <rob@xzilla.net>
Date: 2026-04-05T16:30:41Z
Lists: pgsql-hackers
Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:

> On 2026-Apr-05, Antonin Houska wrote:
> 
> > ok, maybe just skip the whole cleanup in that special case.
> 
> Hmm, should we make this test only in the db_specific case?  Doing it
> unconditionally makes me a bit nervous (maybe because I don't fully
> understand historic snapshot building).

I thought about adding Assert(db_specific) in front of the new return
statement. So what you suggest makes sense to me.

As far as I understand, the xl_running_xacts record is not directly involved
in the snapshot build. Rather, the list of XIDs for snapshots is created and
updated by processing COMMIT and ABORT records.

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



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