HIVE-6500 : Stats collection via filesystem (Ashutosh Chauhan via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1573339 13f79535-47bb-0310-9956-ffa450edef68
HIVE-6429 MapJoinKey has large memory overhead in typical cases (Sergey Shelukhin, reviewed by Gunther Hagleitner, Jitendra Nath Pandey)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1573404 13f79535-47bb-0310-9956-ffa450edef68
HIVE-6393 Support unqualified column references in Joining conditions (Harish Butani via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1573445 13f79535-47bb-0310-9956-ffa450edef68