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Posted to issues@spark.apache.org by "Apache Spark (JIRA)" <ji...@apache.org> on 2017/09/27 00:35:00 UTC

[jira] [Commented] (SPARK-21322) support histogram in filter cardinality estimation

    [ https://issues.apache.org/jira/browse/SPARK-21322?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16181787#comment-16181787 ] 

Apache Spark commented on SPARK-21322:
--------------------------------------

User 'ron8hu' has created a pull request for this issue:
https://github.com/apache/spark/pull/19357

> support histogram in filter cardinality estimation
> --------------------------------------------------
>
>                 Key: SPARK-21322
>                 URL: https://issues.apache.org/jira/browse/SPARK-21322
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>    Affects Versions: 2.3.0
>            Reporter: Ron Hu
>
> Histogram is effective in dealing with skewed distribution.  After we generate histogram information for column statistics, we need to adjust filter estimation based on histogram data structure.



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