Re: REPACK (CONCURRENTLY) rewrites tables marked with user_catalog_table

On Tue, Sep 8, 2026 at 5:47 AM Alvaro Herrera <alvherre(at)kurilemu(dot)de> wrote:
>
> Hello,
>
> On 2026-Sep-04, Masahiko Sawada wrote:
>
> > I reviewed the patch. It's simple and I agree to add a check for user
> > catalog tables. I've slightly rephrased the comment in
> > check_concurrent_repack_requirements() to clarify the reason why
> > REPACK (CONCURRENTLY) doesn't support user catalog tables while it
> > does for normal tables even though it's a MVCC-unsafe operation. Also
> > updated the commit message as well. Please review it.
>
> Thanks, I gave this a look and I think it's okay. I'm not sure about
> the exact wording of the error message though,
>
> > + ereport(ERROR,
> > + errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> > + errmsg("cannot execute %s on relation \"%s\"",
> > + "REPACK (CONCURRENTLY)", RelationGetRelationName(rel)),
> > + errhint("%s is not supported for tables used as catalog tables.",
> > + "REPACK (CONCURRENTLY)"));
>
> ERROR: cannot execute REPACK (CONCURRENTLY) on relation "foobar"
> HINT: REPACK (CONCURRENTLY) is not supported for tables used as catalog tables.
>
> I think the HINT should really be DETAIL, and I'm not sure we need to
> mention the command again there. On the other hand, I'm not really
> happy with the term "tables used as catalog tables". In the
> documentation we use the term "user provided catalog tables" or simply
> "user catalog tables" (see <sect2 id="logicaldecoding-capabilities">).
> So how about something like this?
>
> ERROR: cannot execute REPACK (CONCURRENTLY) on relation "foobar"
> DETAIL: This operation is not supported for user catalog tables.

Looks good to me.

> Would you push this patch, or do you want me to?

I can take it if you are okay, as it's a trivial fix.

Regards,

--
Masahiko Sawada
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