[HIVE-16797] Enhance HiveFilterSetOpTransposeRule to remove union branches

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 3.0.0
• Assignee: Pengcheng Xiong
• Reporter: Pengcheng Xiong
• Created: 31/May/17 21:53
• Updated: 23/May/18 00:00
• Resolved: 20/Jun/17 17:10

Description

in query4.q, we can see that it creates a CTE with union all of 3 branches. Then it is going to do a 3 way self-join of the CTE with predicates. The predicates actually specifies only one of the branch in CTE to participate in the join. Thus, in some cases, e.g.,

               /- filter(false) -----TS0 
union all  - filter(false) -----TS1
               \-----TS2

we can cut the branches of TS0 and TS1. The union becomes only TS2.

Issue Links

• links to: RB