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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Mon, 23 Mar 2026 17:53:59 -0700
Message-ID: 
 <CALj2ACUswwdgrp8U=_EBRCv9qUJD+YUEHwbSziB2TE99Hc4SvA@mail.gmail.com>
Subject: Re: Initial COPY of Logical Replication is too slow
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Jan Wieck <jan@wi3ck.info>, pgsql-hackers@lists.postgresql.org
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Hi,

On Wed, Mar 18, 2026 at 4:29=E2=80=AFPM Masahiko Sawada <sawada.mshk@gmail.=
com> wrote:
>
> I've attached the patch to implement this idea. The patch still
> introduces a new function but it overloads
> pg_get_publication_tables(). We might be able to handle different
> input (array or text) in pg_get_publication_tables() better, but it's
> enough for discussion at least.

Overall, the intent of this patch looks good to me. It avoids the cost
of the table sync worker querying all the pg_publication_rel tables to
filter them out later in the join.

I quickly reviewed the patch and here are some comments:

1/ Typo: s/pg_get_publication_table_info/pg_get_publication_tables

2/ I think it's good to have some quick numbers on how the query
latency looks for pre-V19 and the new one that the table sync worker
executes on the publisher, say, with 100, 1000, and 10000 tables at
least.

3/ + Assert(OidIsValid(target_relid));

Why not error out (by treating it as function input parameter
validation) when target_relid is invalid because asserts go unnoticed
on production systems?

--
Bharath Rupireddy
Amazon Web Services: https://aws.amazon.com