[DRILL-1102] Use same set of keys to distribute rows when planner generates exchange for a join operator.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.4.0
• Assignee: Unassigned
• Reporter: Jinfeng Ni
• Created: 03/Jul/14 01:22
• Updated: 31/Jul/14 06:32
• Resolved: 03/Jul/14 17:50

Description

Today, planner might use a different key sets when generate hash-to-random exchange operator for a join's left and right side.

For instance, if we have join condition :
L1 = R1 and L2 = R2,

Planner may generate a plan where the join's left side is hash distributed using L1, while the right side is hash distributed using (R1, R2). Such plan is not valid, since it would produce wrong query result.

To do that, we need make sure the planner will use the same set of keys when ask for hash distribution for a join's left and right side.