(2014/04/10 22:25), Tom Lane wrote: > Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> writes: >> (2014/04/10 0:08), Tom Lane wrote: >>> TBH I think that's barely the tip of the iceberg of cases where this >>> patch will get the wrong answer. > >>> Also, I don't see it doing anything to check the ordering >>> of multiple index columns > >> I think that the following code in index_pathkeys_are_extensible() would >> check the ordering: >> + if (!pathkeys_contained_in(pathkeys, root->query_pathkeys)) >> + return false; > > Hm ... if you're relying on that, then what's the point of the new loop > at all?
The point is that from the discussion , we allow the index pathkeys to be extended to query_pathkeys if each *remaining* pathkey in query_pathkey is a Var belonging to the indexed relation. The code is confusing, though. Sorry, that is my faults. Thanks,  http://www.postgresql.org/message-id/29637.1389064...@sss.pgh.pa.us Best regards, Etsuro Fujita -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers