Date: Sun, 13 Oct 2019 09:55:17 +0200
From: David Fetter <david@fetter.org>
To: Amit Langote <amitlangote09@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: adding partitioned tables to publications
Message-ID: <20191013075516.GG22891@fetter.org>
References: 
 <CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: 
 <CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ@mail.gmail.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Precedence: bulk

On Mon, Oct 07, 2019 at 09:55:23AM +0900, Amit Langote wrote:
> One cannot currently add partitioned tables to a publication.
> 
> create table p (a int, b int) partition by hash (a);
> create table p1 partition of p for values with (modulus 3, remainder 0);
> create table p2 partition of p for values with (modulus 3, remainder 1);
> create table p3 partition of p for values with (modulus 3, remainder 2);
> 
> create publication publish_p for table p;
> ERROR:  "p" is a partitioned table
> DETAIL:  Adding partitioned tables to publications is not supported.
> HINT:  You can add the table partitions individually.
> 
> One can do this instead:
> 
> create publication publish_p1 for table p1;
> create publication publish_p2 for table p2;
> create publication publish_p3 for table p3;
> 
> but maybe that's too much code to maintain for users.
> 
> I propose that we make this command:
> 
> create publication publish_p for table p;
> 
> automatically add all the partitions to the publication.  Also, any
> future partitions should also be automatically added to the
> publication.  So, publishing a partitioned table automatically
> publishes all of its existing and future partitions.  Attached patch
> implements that.
> 
> What doesn't change with this patch is that the partitions on the
> subscription side still have to match one-to-one with the partitions
> on the publication side, because the changes are still replicated as
> being made to the individual partitions, not as the changes to the
> root partitioned table.  It might be useful to implement that
> functionality on the publication side, because it allows users to
> define the replication target any way they need to, but this patch
> doesn't implement that.

With this patch, is it possible to remove a partition manually from a
subscription, or will it just get automatically re-added at some
point?

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate