Re: Data is copied twice when specifying both child and parent table in publication

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
To: Greg Nancarrow <gregn4422(at)gmail(dot)com>
Cc: Amit Langote <amitlangote09(at)gmail(dot)com>, "houzj(dot)fnst(at)fujitsu(dot)com" <houzj(dot)fnst(at)fujitsu(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>
Subject: Re: Data is copied twice when specifying both child and parent table in publication
Date: 2021-11-04 08:10:48
Message-ID: CAA4eK1+J=xLFEWipZbu0RW76QeYzzCM8BqTpw58=-AhOFgSb3A@mail.gmail.com
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On Thu, Nov 4, 2021 at 12:23 PM Greg Nancarrow <gregn4422(at)gmail(dot)com> wrote:
>
> On Thu, Nov 4, 2021 at 3:13 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On further thinking about this, I think we should define the behavior
> > of replication among partitioned (on the publisher) and
> > non-partitioned (on the subscriber) tables a bit more clearly.
> >
> > - If the "publish_via_partition_root" is set for a publication then we
> > can always replicate to the table with the same name as the root table
> > in publisher.
> > - If the "publish_via_partition_root" is *not* set for a publication
> > then we can always replicate to the tables with the same name as the
> > non-root tables in publisher.
> >
> > Thoughts?
> >
>
> I'd adjust that wording slightly, because "we can always replicate to
> ..." sounds a bit vague, and saying that an option is set or not set
> could be misinterpreted, as the option could be "set" to false.
>
> How about:
>
> - If "publish_via_partition_root" is true for a publication, then data
> is replicated to the table with the same name as the root (i.e.
> partitioned) table in the publisher.
> - If "publish_via_partition_root" is false (the default) for a
> publication, then data is replicated to tables with the same name as
> the non-root (i.e. partition) tables in the publisher.
>

Sounds good to me. If we follow this then I think the patch by Hou-San
is good to solve the first problem as described in his last email [1]?

[1] - https://www.postgresql.org/message-id/OS0PR01MB5716C756312959F293A822C794869%40OS0PR01MB5716.jpnprd01.prod.outlook.com

--
With Regards,
Amit Kapila.

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