[HIVE-12040] CBO: Use CBO, even for the 1 JOIN + GROUP BY case

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 1.3.0, 2.0.0
• Fix Version/s: 1.3.0, 2.0.0
• Component/s: Logical Optimizer
• Assignee: Gopal Vijayaraghavan
• Reporter: Gopal Vijayaraghavan
• Created: 06/Oct/15 00:02
• Updated: 16/Feb/16 23:52
• Resolved: 06/Oct/15 00:06

Description

Hive CBO kicks in for a query only if a query has >1 joins, which is an archaic result of only re-ordering joins in the original impl.

As more group-by & filter optimizers have been added, modify the CBO impl to kick in even if the query has a single JOIN.

Issue Links

• is duplicated by: HIVE-12017 Do not disable CBO by default when number of joins in a query is equal or less than 1