Re: BUG #15352: postgresql FDW error "ERROR: ORDER BY position 0 is not in select list"

>>>>> "Andrew" == Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> writes:

Andrew> It seems obviously wrong that a constant pathkey with no actual
Andrew> reference to the foreign table should be being pushed down, so
Andrew> so far I suspect that get_useful_pathkeys_for_relation isn't
Andrew> being selective enough about what is "useful". In this context
Andrew> I find it suspicious that find_em_expr_for_rel will return an
Andrew> expr with no vars as being "for" every rel, since it's just
Andrew> looking for a subset.

Andrew> So this looks to me like an oversight in aa09cd242 (CCing rhaas
Andrew> and Ashutosh accordingly), which changed find_em_expr_for_rel
Andrew> from using bms_equal to bms_is_subset without considering the
Andrew> degenerate case of members with no relids at all. I propose to
Andrew> simply add a !bms_is_empty condition there; anyone have any
Andrew> better idea?

Pushed this.

--
Andrew (irc:RhodiumToad)