Re: [PATCH] kNN for btree

Attached 6th version of the patches rebased onto current master:
* index_clauses now also passed into ammatchorderby()
* added support for queries like  SELECT * FROM tab WHERE col1 = val1 AND col2 = val2 ORDER BY col3 <-> val3
* (experimental patch #9)  added support for queries like  SELECT * FROM tab WHERE col1 IN (v1, v2, v3) ORDER BY col1, col2 <-> val


Patch #9 is experimental.  In order to distinguish order-by-operator and 
simple order-by-column clauses (index column can be operator expression)
in orderbyclauses lists I am trying to pass negative column numbers in 
orderbyclausecols, but it looks ugly, so I think orderbyclauses passing needs
some refactoring like recent IndexClause refactoring.  Also I doubt that I 
correctly implemented match_pathkey_to_indexcol().

--
Nikita Glukhov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company