[DRILL-6758] Hash Join should not return the join columns when they are not needed downstream

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.14.0
• Component/s: Execution - Relational Operators, Query Planning & Optimization
• Assignee: Hanumath Rao Maduri
• Reporter: Boaz Ben-Zvi
• Created: 22/Sep/18 01:35
• Updated: 23/Mar/20 09:10

Description

Currently the Hash-Join operator returns all its (both sides) incoming columns. In cases where the join columns are not used further downstream, this is a waste (allocating vectors, copying each value, etc).

  Suggestion: Have the planner pass this information to the Hash-Join operator, to enable skipping the return of these columns.