Re: Data is copied twice when specifying both child and parent table in publication - Mailing list pgsql-hackers

On Wed, Mar 29, 2023 at 2:00 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> Pushed.

While rebasing my logical-roots patch over the top of this, I ran into
another situation where mixed viaroot settings can duplicate data. The
key idea is to subscribe to two publications with mixed settings, as
before, and add a partition root that's already been replicated with
viaroot=false to the other publication with viaroot=true.

  pub=# CREATE TABLE part (a int) PARTITION BY RANGE (a);
  pub=# CREATE PUBLICATION pub_all FOR ALL TABLES;
  pub=# CREATE PUBLICATION pub_other FOR TABLE other WITH
(publish_via_partition_root);
  -- populate with data, then switch to subscription side
  sub=# CREATE SUBSCRIPTION sub CONNECTION ... PUBLICATION pub_all, pub_other;
  -- switch back to publication
  pub=# ALTER PUBLICATION pub_other ADD TABLE part;
  -- and back to subscription
  sub=# ALTER SUBSCRIPTION sub REFRESH PUBLICATION;
  -- data is now duplicated

(Standalone reproduction attached.)

This is similar to what happens if you alter the
publish_via_partition_root setting for an existing publication, but
I'd argue it's easier to hit by accident. Is this part of the same
class of bugs, or is it different (or even expected) behavior?

Thanks,
--Jacob