Re: Add support for COPY TO in tablesync for partitioned tables.

Masahiko Sawada <sawada.mshk@gmail.com>

From: Masahiko Sawada <sawada.mshk@gmail.com>

To: Ajin Cherian <itsajin@gmail.com>

Cc: Amit Kapila <amit.kapila16@gmail.com>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>

Date: 2025-11-12T21:49:22Z

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Use "COPY table TO" for partitioned tables in initial table synchronization.
- 266543a62055 19 (unreleased) landed
Support COPY TO for partitioned tables.
- 4bea91f21f61 19 (unreleased) cited

On Mon, Nov 10, 2025 at 7:37 PM Ajin Cherian <itsajin@gmail.com> wrote:
>
> On Tue, Nov 11, 2025 at 2:19 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > In the commit message, you mentioned: "Performance tests show it's
> > faster than the COPY (SELECT ...) TO variant as it avoids the
> > overheads of query processing and sending results to the COPY TO
> > command.". Can you share the performance data to substantiate this
> > point?
> >
>
> This was based on the tests done in the original thread [1] and [2]

Thank you for working on this item. I think it's a good follow-up
patch for commit 4bea91f.

Have you conducted any performance tests with logical replication
setup? I've measured normal COPY TO cases but I think it would be
worth checking how much the performance increase we can see in logical
replication setup too.

Regards,

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