Re: Support EXCEPT for TABLES IN SCHEMA publications

On Thu, Aug 13, 2026 at 12:52 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
>
>
> 2b.
> /In the partition case/For partitions/
>
> AFAICT this case is referring to something like: "FOR TABLE part,
> TABLES IN SCHEMA EXCEPT (part_root)"
>
> But, isn't that just a variation of the 1st case issue? e.g. where
> table "part" is not yet visible for later lookup of "root", then you
> wont be able to check integrity of the partition tree regardless of
> the up/down traversal logic, so I wasn't sure why this 2nd case was
> separately mentioned at all.

The second point is different from the first. Consider this case:

CREATE PUBLICATION pub1 FOR s2.tab_part;
ALTER PUBLICATION pub1 ADD TABLES IN SCHEMA s2 EXCEPT (TABLE tab_root);

Here, the partition entry in pg_publication_rel is visible to the
second command in publication_add_relation() and in
check_publication_add_relation(). But the checks there are not
sufficient to identify the error. If we try to detect the error while
adding tab_root in publication_add_relation(),
we would need to perform a full descendant search to determine whether
any of its descendants are already present in pg_publication_rel. This
downward traversal is what we are trying to avoid in
publication_add_relation(). Geenrally we rely on ancestor-lookup and
we want to stick to that instead of introducing a new logic.
Thus the logic in CheckExceptNotInTableList() is needed here. It reads
all explicitly added entries from pg_publication_rel, looks up their
ancestors to find the root, and checks the EXCEPT entries against that
root.

This is my understanding, let's wait for Nisha's comments as well.

I feel the comment about the second case should be moved to patch002,
where it actually makes sense and explains why it is needed even after
point 1.

thanks
Shveta