Nice job! the patch looks good for me.
By the way, there is something to be checked. TestInsertQuery causes test failures after this patch because the following line causes NPE in some tests.
The main cause is that storeTableNode does not always have PartitionDesc instance.
Besides, I'm expecting that you were very confuse because so far, we have used the word 'partition' to indicate shuffle. So, I've just created an refactoring issue (
TAJO-464) to rename 'partition' actually meaning 'shuffle' to 'shuffle'.