Re: \d with triggers: more than one row returned by a subquery used as an expression

On Mon, Jan 17, 2022 at 05:02:00PM -0500, Tom Lane wrote:
> Justin Pryzby <pryzby(at)telsasoft(dot)com> writes:
> > On Fri, Dec 17, 2021 at 09:43:56AM -0600, Justin Pryzby wrote:
> >> I want to mention that the 2nd problem I mentioned here is still broken.
> >> https://www.postgresql.org/message-id/20210717010259.GU20208@telsasoft.com
> >> It happens if non-inheritted triggers on child and parent have the same name.
>
> > This is the fix I was proposing
> > It depends on pg_partition_ancestors() to return its partitions in order:
> > this partition => parent => ... => root.
>
> I don't think that works at all. I might be willing to accept the
> assumption about pg_partition_ancestors()'s behavior, but you're also
> making an assumption about how the output of pg_partition_ancestors()
> is joined to "pg_trigger AS u", and I really don't think that's safe.

> ISTM the real problem is the assumption that only related triggers could
> share a tgname, which evidently isn't true. I think this query needs to
> actually match on tgparentid, rather than taking shortcuts.

I don't think that should be needed - tgparentid should match
pg_partition_ancestors().

> If we don't
> want to use a recursive CTE, maybe we could define it as only looking up to
> the immediate parent, rather than necessarily finding the root?

I think that defeats the intent of c33869cc3.

Is there any reason why WITH ORDINALITY can't work ?
This is passing the smoke test.

--
Justin