amplab/shark — pull request #100 by shimingfei (2013-06-19 15:14:26+00:00)
Title: add copartition join to Shark

Port from old Shark code, made some changes:
1.check whether join on partition columns or not
2.needn't use distribute by when cache tables.
eg:
set shark.copartition.partnum=128;
CREATE TABLE sales_cached TBLPROPERTIES("shark.partition.col"="_col3") AS select * from sales;
CREATE TABLE item_cached TBLPROPERTIES("shark.copartition.table"="sales_cached", "shark.partition.col"="_col0") AS select * from item;