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https://issues.apache.org/jira/browse/HIVE-10989?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14585420#comment-14585420
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Xuefu Zhang commented on HIVE-10989:
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[~lirui], Thanks for working on this. Changes look good except that I don't
quite understand the 3rd part of the change. Could you please explain? Thanks.
> HoS can't control number of map tasks for runtime skew join [Spark Branch]
> --------------------------------------------------------------------------
>
> Key: HIVE-10989
> URL: https://issues.apache.org/jira/browse/HIVE-10989
> Project: Hive
> Issue Type: Sub-task
> Components: Spark
> Reporter: Rui Li
> Assignee: Rui Li
> Attachments: HIVE-10989.1-spark.patch
>
>
> Flags {{hive.skewjoin.mapjoin.map.tasks}} and
> {{hive.skewjoin.mapjoin.min.split}} are used to control the number of map
> tasks for the map join of runtime skew join. They work well for MR but have
> no effect for spark.
> This makes runtime skew join less useful, i.e. we just end up with slow
> mappers instead of reducers.
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