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https://issues.apache.org/jira/browse/HIVE-8649?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14201151#comment-14201151
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Xuefu Zhang commented on HIVE-8649:
-----------------------------------
+1
> Increase level of parallelism in reduce phase [Spark Branch]
> ------------------------------------------------------------
>
> Key: HIVE-8649
> URL: https://issues.apache.org/jira/browse/HIVE-8649
> Project: Hive
> Issue Type: Sub-task
> Components: Spark
> Reporter: Brock Noland
> Assignee: Jimmy Xiang
> Fix For: spark-branch
>
> Attachments: HIVE-8649.1-spark.patch, HIVE-8649.2-spark.patch
>
>
> We calculate the number of reducers based on the same code for MapReduce.
> However, reducers are vastly cheaper in Spark and it's generally recommended
> we have many more reducers than in MR.
> Sandy Ryza who works on Spark has some ideas about a heuristic.
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