Horton
Menu

Re: Adding REPACK [concurrently]

Antonin Houska <ah@cybertec.at>

View thread
From: Antonin Houska <ah@cybertec.at>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Amit Kapila <amit.kapila16@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, 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: 2026-04-18T19:23:08Z
Lists: pgsql-hackers

Attachments

Mihail Nikalayeu <mihailnikalayeu@gmail.com> wrote:

> I think I got working POC for deadlock-detector enhancements for
> REPACK (and potentially other).

That looks interesting, I'll check it.

I've also thought about the problem quite a bit this week. I tried to add a
pointer to PGPROC that, like ->waitLock, points to the lock being acquired,
but it's initialized before the actual waiting starts. I adjusted the deadlock
detector to use that pointer too, but it did not work. The problem was
probably that the lock wasn't in the queue during the check.

Finally it occurred to me that a new field can be added to the LOCK structure,
indicating that the lock is being upgraded. It enforces some extra deadlock
checks by other processes, so that the upgrading process does not have to care
about deadlock detection at all. More info in the commit message.

It should handle all the cases in your tests, however a new injection point
would be needed. (Not added yet.)

-- 
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