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From: Masahiko Sawada <sawada.mshk@gmail.com>
Date: Mon, 30 Mar 2026 18:00:23 -0700
Message-ID: 
 <CAD21AoBXwt1SvigufcORRtxBpavWuc5HZagpAejiMgzVZ0xW8Q@mail.gmail.com>
Subject: Re: Initial COPY of Logical Replication is too slow
To: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Jan Wieck <jan@wi3ck.info>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
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On Mon, Mar 30, 2026 at 12:42=E2=80=AFAM Hayato Kuroda (Fujitsu)
<kuroda.hayato@fujitsu.com> wrote:
>
> Dear Sawada-san,
>
> Thanks for updating the patch. I think the patch has a good shape.
> Below contains minor comments.

Thank you for the comments!

>
>
> ```
> +               if (filter_by_relid)
> +                       relkind =3D get_rel_relkind(target_relid);
> ```
>
> Can we return here if the relkind is not RELKIND_RELATION nor RELKIND_PAR=
TITIONED_TABLE?
> Key assumption here is that pg_get_publication_tables_b() returns at most=
 one
> tuple, thus this is would be called only once.

Yeah, I refactored these logic and do the preliminary check before
checking the publications.

>
> ```
> +       /*
> +        * Non-alltables
> +        */
> +       if (relispartition)
> ```
>
> else-if might be usalbe to clarify we're in the non-alltables case.

Hmm, we have the return statement at the end of the if branch so we
don't necessarily need else-if. Adding a new line after the comment
might help readability.

>
> ```
> +               Assert(pubnames !=3D NULL);
> ```
>
> Personally I prefer to do Assert() before the SRF_FIRSTCALL_INIT(). Becau=
se it's
> only related with argument and not related with other function calls.

If we move it before the SRF_FIRSTCALL_INIT(), we would end up
executing the assertion every time we call
pg_get_publication_table_b() since it could return more than one
tuple, which seems unnecessary to me. I think we can remove this
assertion because both _a() and _b() are strict functions.

>
> ```
> +  proname =3D> 'pg_get_publication_tables', prorows =3D> '10',
> ```
>
> Can prorows be 1? Because only a row would be returned here.
>

If multiple publications are specified, it could return more than one tuple=
s.

I'll submit the updated patch soon.

Regards,

--=20
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com