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https://issues.apache.org/jira/browse/DRILL-6758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16624553#comment-16624553
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Volodymyr Vysotskyi commented on DRILL-6758:
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In this example, only columns which are used in downstream operators and
columns from join condition are returned by join operator. Is the proposal do
not return columns from join condition if they are not used in downstream?
> Hash Join should not return the join columns when they are not needed
> downstream
> --------------------------------------------------------------------------------
>
> Key: DRILL-6758
> URL: https://issues.apache.org/jira/browse/DRILL-6758
> Project: Apache Drill
> Issue Type: Improvement
> Components: Execution - Relational Operators, Query Planning &
> Optimization
> Affects Versions: 1.14.0
> Reporter: Boaz Ben-Zvi
> Assignee: Hanumath Rao Maduri
> Priority: Minor
> Fix For: 1.15.0
>
>
> 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.
>
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