[HIVE-9039] Support Union Distinct

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Component/s: Query Planning
• Assignee: Pengcheng Xiong
• Reporter: Pengcheng Xiong
• Created: 08/Dec/14 06:04
• Updated: 14/Jul/16 01:10
• Resolved: 09/Feb/15 18:08

Description

CLEAR LIBRARY CACHE

Current version (Hive 0.14) does not support union (or union distinct). It only supports union all. In this patch, we try to add this new feature by rewriting union distinct to union all followed by group by.

Issue Links

• Is contained by: HIVE-12764 Support Intersect (distinct/all) Except (distinct/all) Minus (distinct/all) in Hive
• is related to: HIVE-9217 UnionProcessor misses results for multi-insert when hive.optimize.union.remove=true
• is related to: HIVE-3185 allow union set operation without ALL keyword (align to ISO-SQL 2011 specification)
• relates to: HIVE-9055 Tez: union all followed by group by followed by another union all gives error
• relates to: HIVE-9002 union all does not generate correct result for order by and limit
• relates to: HIVE-9053 select constant in union all followed by group by gives wrong result
• relates to: HIVE-9141 HiveOnTez: mix of union all, distinct, group by generates error
• relates to: HIVE-8385 UNION Operator in Hive
• links to: RB