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Re: Adding REPACK [concurrently]

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Antonin Houska <ah@cybertec.at>, Andres Freund <andres@anarazel.de>, 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>
Date: 2026-06-17T18:19:20Z
Lists: pgsql-hackers 
Hello Mihail,

On 2026-Jun-03, Mihail Nikalayeu wrote:

> Hello, everyone!
> 
> I think it is a good time to remind we still have a potential deadlock
> issue leading to loosing vast amount of REPACK work.
> 
> Best soltuion I was able to craft so far is [1].

> [1]: https://www.postgresql.org/message-id/flat/CADzfLwXbUWuS6H4uJEFVL1jS1kzsVnuJ%2BzX1%2BtAEhQxBnEiGKw%40mail.gmail.com

Right.  I spent some time looking at this patch just before pgconf.dev,
and I have to admit I was a bit scared -- that code is really
non-obvious, and breakage here could mean big trouble in case something
goes wrong in weird situations.

So I think we should let this slip for pg19, and get this patch reviewed
and pushed early in pg20 in the coming weeks, so that we have more of a
chance to discover breakage in the time until pg20 release next year.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Por suerte hoy explotó el califont porque si no me habría muerto
 de aburrido"  (Papelucho)

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