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https://issues.apache.org/jira/browse/SPARK-33486?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Prakhar Jain updated SPARK-33486:
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Issue Type: Improvement (was: Task)
> Collapse Partial and Final Aggregation into Complete Aggregation mode
> ---------------------------------------------------------------------
>
> Key: SPARK-33486
> URL: https://issues.apache.org/jira/browse/SPARK-33486
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 2.3.4, 2.4.7, 3.0.0, 3.0.1
> Reporter: Prakhar Jain
> Priority: Major
>
> We should merge the Partial and Final Aggregation into one if there is no
> exchange between them.
>
> Example: select col1, max(col2) from t1 join t2 on col1 group by col1
> In this case, after the SortMergeJoin, Spark will do PartialAggregation and
> then FinalAggregation. So it will create HashTables two times which is not
> required. If there is lot of data after Join with many distinct col1's then
> there is a possibility of Spill also in HashAggregateExec. So Spill will also
> happen twice which can be avoided.
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