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https://issues.apache.org/jira/browse/SPARK-38399?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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mengdou updated SPARK-38399:
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    Attachment: image-2022-03-03-16-34-17-909.png

> Why doesn't shuffle hash join support build left table for left-outer-join 
> but full-outer-join?
> -----------------------------------------------------------------------------------------------
>
>                 Key: SPARK-38399
>                 URL: https://issues.apache.org/jira/browse/SPARK-38399
>             Project: Spark
>          Issue Type: Question
>          Components: Spark Core, SQL
>    Affects Versions: 3.2.0
>            Reporter: mengdou
>            Priority: Minor
>         Attachments: image-2022-03-03-16-34-17-909.png
>
>
> Why doesn't shuffle hash join support building left table for 
> left-outer-join, but it supports building right table for full-outer-join?
> !image-2022-03-03-13-53-50-520.png!
>  
> IMO, if left table is the build table, similar to full-outer-table,  we can 
> first create a BitSet to record any mismatch of next joins, and iterate all 
> rows from stream table iterator and look up the hash key in the hash 
> relation.  
> If no one from stream table can join with the built hash relation, then we 
> iterate the hash relation and get relative value from the BitSet, so we can 
> get the left-outer rows.
>  
> Does anyone helps? Thx~
>  
>  



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