[jira] [Commented] (HIVE-13293) Query occurs performance degradation after enabling parallel order by for Hive on Spark

["Xuefu Zhang (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-13293?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15237434#comment-15237434 ] 

Xuefu Zhang commented on HIVE-13293:
------------------------------------

[~lirui], thanks for the investigation and the patch, which seems simple and straightforward. One question: what do you mean by "only works queries that have only one ShuffleMapStage"? In your previous example, there are actually a few such stages. Isn't your patch supposed to help that as well?

> Query occurs performance degradation after enabling parallel order by for Hive on Spark
> ---------------------------------------------------------------------------------------
>
>                 Key: HIVE-13293
>                 URL: https://issues.apache.org/jira/browse/HIVE-13293
>             Project: Hive
>          Issue Type: Bug
>          Components: Spark
>    Affects Versions: 2.0.0
>            Reporter: Lifeng Wang
>            Assignee: Rui Li
>         Attachments: HIVE-13293.1.patch
>
>
> I use TPCx-BB to do some performance test on Hive on Spark engine. And found query 10 has performance degradation when enabling parallel order by.
> It seems that sampling cost much time before running the real query.



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