Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
> On Tue, Jul 2, 2019 at 9:19 PM Nikita Glukhov <n.gluhov@postgrespro.ru> wrote:
>> We could use commuted "const <-> var" operators for kNN searches, but the
>> current implementation requires the existence of "var <-> const" operators, and
>> order-by-op clauses are rebuilt using them (see match_clause_to_ordering_op()
>> at /src/backend/optimizer/path/indxpath.c).
> But probably it's still worth to just add commutator for every <->
> operator and close this question.
Yeah, I was just thinking that it was weird not to have the commutator
operators, independently of indexing considerations. Seems like a
usability thing.
regards, tom lane