Review Board 1.7.22


add support for insert partition overwrite(...) if not exists

Review Request #2974 - Created Nov. 30, 2011 and updated

chinna
trunk
HIVE-2602
Reviewers
hive
namit
hive
INSERT OVERWRITE TABLE X PARTITION (a=b, c=d) IF NOT EXISTS ...
The partition should be created and written if and only if it's not there already. 
Added a check to validate the partition exist or not.
all tests passed and added new testcases