Re: pg_get_publication_tables() output duplicate relid

On Fri, Dec 3, 2021 at 21:34 Amit Langote <amitlangote09(at)gmail(dot)com> wrote:

> On Fri, Dec 3, 2021 at 12:37 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
> > On Thu, Dec 2, 2021 at 7:18 PM Amit Langote <amitlangote09(at)gmail(dot)com>
> wrote:
> > > On Thu, Dec 2, 2021 at 2:27 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
> > > > On Thu, Dec 2, 2021 at 8:42 AM Amit Langote <amitlangote09(at)gmail(dot)com>
> wrote:
> > > > > Reading Alvaro's email at the top again gave me a pause to
> reconsider
> > > > > what I had said in reply. It might indeed have been nice if the
> > > > > publication DDL itself had prevented the cases where a partition
> and
> > > > > its ancestor are added to a publication, though as Hou-san
> mentioned,
> > > > > partition ATTACHes make that a bit tricky to enforce at all times,
> > > > > though of course not impossible. Maybe it's okay to just
> de-duplicate
> > > > > pg_publication_tables output as the patch does, even though it may
> > > > > appear to be a band-aid solution if we one considers Alvaro's point
> > > > > about consistency.
> > > >
> > > > True, I think even if we consider that idea it will be a much bigger
> > > > change, and also as it will be a behavioral change so we might want
> to
> > > > keep it just for HEAD and some of these fixes need to be backpatched.
> > > > Having said that, if you or someone want to pursue that idea and come
> > > > up with a better solution than what we have currently it is certainly
> > > > welcome.
> > >
> > > Okay, I did write a PoC patch this morning after sending out my
> > > earlier email. I polished it a bit, which is attached.
> >
> > I see multiple problems with this patch and idea.
>
> Thanks for looking at it. Yeah, I have not looked very closely at ALL
> TABLES [IN SCHEMA], though only because I suspected that those cases
> deal with partitioning in such a way that the partition duplication
> issue doesn't arise. That is, only the FOR TABLE list_of_tables and
> ADD TABLE syntax allow for the duplication issue to occur.

Another thing I forgot to mention is that the patch passes check-world.
Perhaps we don’t have enough tests that would’ve exposed any problems with
the patch’s approach.
--
Amit Langote
EDB: http://www.enterprisedb.com