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From: vignesh C <vignesh21@gmail.com>
Date: Mon, 7 Mar 2022 10:50:35 +0530
Message-ID: <CALDaNm3GQFVGeKg18wUe1-toXd_80=AW+JOW9KQySVbL8Tz4WA@mail.gmail.com>
Subject: Re: Handle infinite recursion in logical replication setup
To: Peter Smith <smithpb2250@gmail.com>
Cc: "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com>, 
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Mon, Mar 7, 2022 at 10:26 AM Peter Smith <smithpb2250@gmail.com> wrote:
>
> Hi Vignesh, I also have not looked at the patch yet, but I have what
> seems like a very fundamental (and possibly dumb) question...
>
> Basically, I do not understand the choice of syntax for setting things up.
>
> IMO that "only-local" option sounds very similar to the other
> PUBLICATION ("publish") options which decide the kinds of things that
> will be published. So it feels more natural for me to think of the
> publisher as being the one to decide what will be published.
>
> e.g.
>
> option 1:
> CREATE PUBLICATION p1 FOR TABLE t1;
> CREATE SUBSCRITION s1 ... FOR PUBLICATION p1 WITH (only_local = true);
>
> option 2:
> CREATE PUBLICATION p1 FOR TABLE t1 WEHRE (publish = 'only_local');
> CREATE SUBSCRITION s1 ... FOR PUBLICATION p1;
>
> ~~
>
> IIUC the patch is using option 1. My first impression was it feels
> back-to-front for the SUBSCRIPTION telling the PUBLICATION what to
> publish.
>
> So, why does the patch use syntax option 1?

I felt the advantage with keeping it at the subscription side is that,
the subscriber from one node can subscribe with only_local option on
and a different subscriber from a different node can subscribe with
only_local option as off. This might not be possible with having the
option at publisher side. Having it at the subscriber side might give
more flexibility for the user.

Regards,
Vignesh