Re: Adding REPACK [concurrently]

Fujii Masao <masao.fujii@gmail.com>

From: Fujii Masao <masao.fujii@gmail.com>

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

Cc: Robert Treat <rob@xzilla.net>, Pg Hackers <pgsql-hackers@lists.postgresql.org>, Antonin Houska <ah@cybertec.at>

Date: 2025-08-01T11:07:05Z

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 →

Improve REPACK (CONCURRENTLY) error messages some more
- 378dffaf8c80 19 (unreleased) landed
Add CONCURRENTLY option to REPACK
- 28d534e2ae0a 19 (unreleased) landed
Make index_concurrently_create_copy more general
- 33bf7318f94c 19 (unreleased) landed
Document the 'command' column of pg_stat_progress_repack
- a630ac5c2016 19 (unreleased) landed
Introduce the REPACK command
- ac58465e0618 19 (unreleased) landed
Split vacuumdb to create vacuuming.c/h
- c4067383cb2c 19 (unreleased) landed
Revert changes to CONCURRENTLY that "sped up" Xmin advance
- 042b584c7f7d 14.4 cited

On Fri, Aug 1, 2025 at 1:50 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> One of the later patches in the series, which I have not included yet,
> intends to implement the idea of transiently enabling wal_level=logical
> for the table being repacked concurrently, so that you can still use
> the concurrent mode if you have a non-logical-wal_level instance.

Sounds good to me!

> Here's v17.

I just tried REPACK command and observed a few things:

When I repeatedly ran REPACK on the regression database
while make installcheck was running, I got the following error:

        ERROR:  StartTransactionCommand: unexpected state STARTED

"REPACK (VERBOSE);" failed with the following error.

        ERROR:  syntax error at or near ";"

REPACK (CONCURRENTLY) USING INDEX failed with the following error,
while the same command without CONCURRENTLY completed successfully:

        =# REPACK (CONCURRENTLY) parallel_vacuum_table using index
regular_sized_index ;
        ERROR:  cannot process relation "parallel_vacuum_table"
        HINT:  Relation "parallel_vacuum_table" has no identity index.

When I ran REPACK (CONCURRENTLY) on a table that's also a logical
replication target, I saw the following log messages. Is this expected?

        =# REPACK (CONCURRENTLY) t;
        LOG:  logical decoding found consistent point at 1/00021F20
        DETAIL:  There are no running transactions.
        STATEMENT:  REPACK (CONCURRENTLY) t;

Regards,

-- 
Fujii Masao