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https://issues.apache.org/jira/browse/SPARK-4570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Reynold Xin updated SPARK-4570:
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Assignee: XiaoJing wang
> Add broadcast join to left semi join
> -------------------------------------
>
> Key: SPARK-4570
> URL: https://issues.apache.org/jira/browse/SPARK-4570
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 1.1.0
> Reporter: XiaoJing wang
> Assignee: XiaoJing wang
> Priority: Minor
> Fix For: 1.3.0
>
>
> For now, spark use broadcast join instead of hash join to optimize {{inner
> join}} when the size of one side data did not reach the
> {{AUTO_BROADCASTJOIN_THRESHOLD}}
> However,Spark SQL will perform shuffle operations on each child relations
> while executing {{left semi join}} is more suitable for optimiztion with
> broadcast join.
> We are planning to create a{{BroadcastLeftSemiJoinHash}} to implement the
> broadcast join for {{left semi join}}
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