mongodb/mongo — pull request #664 by santoshbanda (2014-04-07 21:42:35+00:00)
Title: SERVER-2227 add index usage statistics

Summary:
db.collection.stats() shows a field indexStats which has
the index usage statistics i.e; number of queries which used the index.

Test Plan:
verified the output of db.collection.stats() after running
few queries on a collection with indexes.