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

On Wed, Nov 3, 2021 at 3:43 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Oct 28, 2021 at 1:55 PM Amit Langote <amitlangote09(at)gmail(dot)com> wrote:
> >
> >
> > Thanks for the summary, Hou-san, and sorry about my late reply.
> >
> > I had thought about this some last week and I am coming around to
> > recognizing the confusing user experience of the current behavior.
> > Though, I am not sure if removing partitions from the result of
> > pg_publication_tables view for pubviaroot publications is acceptable
> > as a fix, because that prevents replicating into a subscriber node
> > where tables that are partition root and a partition respectively on
> > the publisher are independent tables on the subscriber.
> >
>
> But we already do that way when the publication is "For All Tables".
> Anyway, for the purpose of initial sync, it will just replicate the
> same data in two different tables if the corresponding tables on the
> subscriber-side are non-partitioned which I am not sure is what the
> user will be expecting.
>

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?

--
With Regards,
Amit Kapila.