mongodb/mongo — pull request #596 by dstorch (2013-12-31 19:18:11+00:00)
Title: SERVER-10564 plan cache data storage mechanism

The plan cache now builds a tree isomorphic to the tagged match expression in order to store the index tags used by a plan. On cache hit, this tree is used to tag the match expression. The tagged tree can then be fed through the access planner in order to recreate the original query solution.