Horton

Re: Adding REPACK [concurrently]

Antonin Houska <ah@cybertec.at>

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From: Antonin Houska <ah@cybertec.at>
To: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Pg Hackers <pgsql-hackers@lists.postgresql.org>, Robert Treat <rob@xzilla.net>
Date: 2025-11-03T07:56:40Z
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 →

  1. Improve REPACK (CONCURRENTLY) error messages some more

  2. Add CONCURRENTLY option to REPACK

  3. Make index_concurrently_create_copy more general

  4. Document the 'command' column of pg_stat_progress_repack

  5. Introduce the REPACK command

  6. Split vacuumdb to create vacuuming.c/h

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

Mihail Nikalayeu <mihailnikalayeu@gmail.com> wrote:

> Hello!
> 
> On Fri, Oct 31, 2025 at 12:17 AM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> > Here's a new installment of this series, v25, including the CONCURRENTLY
> > part, which required some conflict fixes on top of the much-changed
> > v24-0001 patch.
> 
>  > * cluster.c
>  > *      CLUSTER a table on an index.  This is now also used for VACUUM FULL.

ok

>  Should we add something about repack here?
> 
>  > ii_ExclusinOps
>  typo here.

ok

>  >  * index is inserted into catalogs and needs to be built later on.
>  Now it is only in case concurrently == true

ok

> >   * Build the index information for the new index.  Note that rebuild of
> >   * indexes with exclusion constraints is not supported, hence there is no
> >   * need to fill all the ii_Exclusion* fields.
> 
> Now the function supports its in !concurrently mode. Should we fill
> ii_Exclusion? Also, it says
> 
> > If !concurrently, ii_ExclusinOps is currently not needed.

> But it is not clear - why not?

Right, makeIndexInfo() needs to be adjusted.

> 
> >   newInfo = makeIndexInfo(oldInfo->ii_NumIndexAttrs,
> >                           oldInfo->ii_NumIndexKeyAttrs,
> >                           oldInfo->ii_Am,
> >                           indexExprs,
> >                           indexPreds,
> >                           oldInfo->ii_Unique,
> >                           oldInfo->ii_NullsNotDistinct,
> >                           false,  /* not ready for inserts */
> >                           true,
> >                           indexRelation->rd_indam->amsummarizing,
> >                           oldInfo->ii_WithoutOverlaps);
> 
> Is it ok we pass isready == false if !concurrent?
> Also, we pass concurrent == true even if concurrently == false - feels
> strange and probably wrong.

You're right, both arguments are wrong.

> > This difference does has no impact on XidInMVCCSnapshot().
> Should it be "This difference has no impact"?

ok

> > * pgoutput_cluster.c
> > *       src/backend/replication/pgoutput_cluster/pgoutput_cluster.c
>  it is pgoutput_trepack.c :)

ok

I'll fix all the problems in the next version. Thanks!

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