Re: "could not find pathkey item to sort" for TPC-DS queries 94-96

On Sat, Apr 17, 2021 at 3:39 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> ...
> Also, I don't much care for either the name or API of
> find_em_expr_usable_for_sorting_rel.  The sole current caller only
> really needs a boolean result, and if it did need more than that
> it'd likely need the whole EquivalenceMember not just the em_expr
> (certainly createplan.c does).  So 0002 attached is some bikeshedding
> on that.  I kept that separate because it might be wise to do it only
> in HEAD, just in case somebody out there is calling the function from
> an extension.

I forgot to comment on this in my previous email, but it seems to me
that relation_has_safe_ec_member, while less wordy, isn't quite
descriptive enough. Perhaps something like
relation_has_sort_safe_ec_member?

James Coleman