[IMPALA-11074] Elimination of outer joins, if the predicates can restrict the result sets so that all null-supplying rows are eliminated

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Epic Color: ghx-label-1
• Assignee: Unassigned
• Reporter: vinson0526
• Created: 14/Jan/22 11:06
• Updated: 17/Apr/22 12:18
• Resolved: 18/Jan/22 07:53

Description

I found that impala do not have this feature yet when i develop this feature in Apache Doris.

So i want to contribute this feature to impala in the meantime.

Doris issue could be found in this link

The key idea describe below:

Elimination of outer joins, if the predicates can restrict the result sets s
all null-supplying rows are eliminated

• full outer -> inner if both sides have such predicates
• left outer -> inner if the right side has such predicates
• right outer -> inner if the left side has such predicates
• full outer -> left outer if only the left side has such predicates
• full outer -> right outer if only the right side has such predicates

Issue Links

• duplicates: IMPALA-5022 Outer join simplification