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From: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Date: Sat, 1 Nov 2025 19:16:00 +0100
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 <CADzfLwWdc1KBZ2qNV1x7gmZtHdmAYOoq0A2Rw72O2-wEou=FRg@mail.gmail.com>
Subject: Re: Adding REPACK [concurrently]
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>,
 Antonin Houska <ah@cybertec.at>,
	Robert Treat <rob@xzilla.net>
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Hello!

On Fri, Oct 31, 2025 at 12:17=E2=80=AFAM Alvaro Herrera <alvherre@alvh.no-i=
p.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 FU=
LL.

 Should we add something about repack here?

 > ii_ExclusinOps
 typo here.

 >  * index is inserted into catalogs and needs to be built later on.
 Now it is only in case concurrently =3D=3D true

>   * Build the index information for the new index.  Note that rebuild of
>   * indexes with exclusion constraints is not supported, hence there is n=
o
>   * 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?

>   newInfo =3D 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 =3D=3D false if !concurrent?
Also, we pass concurrent =3D=3D true even if concurrently =3D=3D false - fe=
els
strange and probably wrong.


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

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

Best regards,
Mikhail.