HIVE-4486 FetchOperator slows down SMB map joins by 50% when there are many 
partitions (Gopal V via omalley)


git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1483874 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-YAHOO-321-trunk-gd