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https://issues.apache.org/jira/browse/HIVE-8913?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14242813#comment-14242813
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Chao commented on HIVE-8913:
----------------------------

different record handler threads should process different partitions of the RDD.
Without being cached, each such thread should go through {{HadoopRDD#compute}}, 
and have IOContext initialized.

The issue here is, I think, a thread can be assigned to a {{ShuffleMapTask}}, 
which will get the input RDD through broadcast variables. And, hence, that 
thread won't go through {{HadoopRDD#compute}}.

> Make SparkMapJoinResolver handle runtime skew join [Spark Branch]
> -----------------------------------------------------------------
>
>                 Key: HIVE-8913
>                 URL: https://issues.apache.org/jira/browse/HIVE-8913
>             Project: Hive
>          Issue Type: Improvement
>          Components: Spark
>            Reporter: Rui Li
>            Assignee: Rui Li
>         Attachments: HIVE-8913.1-spark.patch, HIVE-8913.2-spark.patch
>
>
> Sub-task of HIVE-8406.
> Now we have {{SparkMapJoinResolver}} in place. But at the moment, it doesn't 
> handle the map join task created by upstream SkewJoinResolver, i.e. those 
> wrapped in a ConditionalTask. We have to implement this part for runtime skew 
> join to work on spark. To do so, we can borrow logic from {{MapJoinResolver}}.



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