[jira] Commented: (HIVE-1093) Add a "skew join map join size" variable to control the input size of skew join's following map join job.

["Namit Jain (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-1093?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12804395#action_12804395 ] 

Namit Jain commented on HIVE-1093:
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Do you have performance numbers for the testcase ? I mean, small map size will lead to more mappers each of which is reading the 
other tables. 

> Add a "skew join map join size" variable to control the input size of skew join's following map join job.
> ---------------------------------------------------------------------------------------------------------
>
>                 Key: HIVE-1093
>                 URL: https://issues.apache.org/jira/browse/HIVE-1093
>             Project: Hadoop Hive
>          Issue Type: Improvement
>            Reporter: He Yongqiang
>            Assignee: He Yongqiang
>
> In a test, many skew join key itself >250M size. And the following mapjoin will take several hours to do a mapjoin for those big skew keys. 
> This can be better by using a small map input size for the following map join job.

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