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

On Sat, Mar 18, 2023 at 5:06 AM Jacob Champion <jchampion(at)timescale(dot)com> wrote:
>
> On Thu, Mar 16, 2023 at 11:28 PM wangw(dot)fnst(at)fujitsu(dot)com
> <wangw(dot)fnst(at)fujitsu(dot)com> wrote:
> > Attach the new patch set.
>
> Hi,
>
> I ran into this problem while hacking on [1], so thank you for tackling
> it! I have no strong opinions on the implementation itself; I just want
> to register a concern that the tests have not kept up with the
> implementation complexity.
>
> For example, the corner case mentioned in 0003, with multiple
> publications having conflicting pubviaroot settings, isn't tested as far
> as I can see. (I checked manually, and it appears to work as intended.)
> And the related pub_lower_level test currently only covers the case
> where multiple publications have pubviaroot=true, so the following test
> comment is now misleading:
>
> > # for tab4, we publish changes through the "middle" partitioned table
> > $node_publisher->safe_psql('postgres',
> > "CREATE PUBLICATION pub_lower_level FOR TABLE tab4_1 WITH (publish_via_partition_root = true)"
> > );
>
> ...since the changes are now in fact published via the tab4 root after
> this patchset is applied.
>
> > I think the aim of joining it with pg_publication before is to exclude
> > non-existing publications. Otherwise, we would get an error because of the call
> > to function GetPublicationByName (with 'missing_ok = false') in function
> > pg_get_publication_tables.
>
> In the same vein, I don't think that case is covered anywhere.
>

We can have a test case to cover this scenario.

> There are a bunch of moving parts and hidden subtleties here, and I fell
> into a few traps when I was working on my patch, so it'd be nice to have
> additional coverage. I'm happy to contribute effort in that area if it's
> helpful.
>

I think it depends on what tests you have in mind. I suggest you can
propose a patch to cover tests for this are in a separate thread. We
can then evaluate those separately.

--
With Regards,
Amit Kapila.