[HIVE-16602] Implement shared scans with Tez

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: Physical Optimizer
• Target Version/s: 3.0.0
• Assignee: Jesús Camacho Rodríguez
• Reporter: Jesús Camacho Rodríguez
• Created: 08/May/17 10:10
• Updated: 27/Feb/24 22:23
• Resolved: 13/May/17 07:10

Description

Given a query plan, the goal is to identify scans on input tables that can be merged so the data is read only once. Optimization will be carried out at the physical level.

In the longer term, identification of equivalent expressions and reutilization of intermediary results should be done at the logical layer via Spool operator.

Issue Links

• is related to: HIVE-16717 Extend shared scan optimizer to handle partitions
• is related to: HIVE-16867 Extend shared scan optimizer to reuse computation from other operators
• relates to: HIVE-16414 [Hive on Tez] Hive Union queries resource efficiency less on Tez than Mapreduce
• links to: RB link