On Thu, May 3, 2018 at 7:31 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Ah, I think it's just an order-of-visitation issue then. There are
> dependencies at both the column and whole-table level, specifically
>
> schema collate_tests -> table collate_test4
> schema collate_tests -> domain testdomain_p -> column collate_test4.b
>
> I think if we already know that table collate_test4 is scheduled to be
> deleted, we just ignore column collate_test4.b when the recursion reaches
> that ... but if we visit those two things in the other order, then both
> will be reported as deletion targets. And it's not surprising that
> disabling indexscans on pg_depend changes the visitation order.
I also noticed that there are cases where we see less helpful (though
still technically correct) HINT messages about which other object the
user may prefer to drop.
--
Peter Geoghegan