[HIVE-16462] Vectorization: Enabling hybrid grace disables specialization of all reduce side joins

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Vectorization
• Assignee: Jason Dere
• Reporter: Jason Dere
• Created: 17/Apr/17 23:12
• Updated: 22/May/18 23:58
• Resolved: 18/Apr/17 23:31

Description

Observed by gopalv.

Having grace hash join enabled prevents the specialized vector hash joins during the vectorizer stage of query planning. However hive.llap.enable.grace.join.in.llap will later disable grace hash join (LlapDecider runs after Vectorizer). If we can disable the grace hash join before vectorization kicks in then we can still benefit from the specialized vector hash joins.

This can be special cased for the llap.execution.mode=only case.