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From "Cheng Hao (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (SPARK-4636) Cluster By & Distribute By output different with Hive
Date Fri, 09 Jan 2015 02:57:35 GMT

    [ https://issues.apache.org/jira/browse/SPARK-4636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14270466#comment-14270466
] 

Cheng Hao edited comment on SPARK-4636 at 1/9/15 2:56 AM:
----------------------------------------------------------

The answer with highest score in StackOverFlow seems not correct, in might tested with the
Hive local mode, which always take a single reducer.


was (Author: chenghao):
The answer with highest score seems not correct, in might tested with the Hive local mode,
which always take a single reducer.

> Cluster By & Distribute By output different with Hive
> -----------------------------------------------------
>
>                 Key: SPARK-4636
>                 URL: https://issues.apache.org/jira/browse/SPARK-4636
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>            Reporter: Cheng Hao
>
> This is a very interesting bug.
> Semantically, Cluster By & Distribute By will not cause a global ordering, as described
in Hive wiki:
> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+SortBy
> However, the partition keys are sorted in MapReduce after shuffle, so from the user point
of view, the partition key itself is global ordered, and it may looks like:
> http://stackoverflow.com/questions/13715044/hive-cluster-by-vs-order-by-vs-sort-by



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