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From "Ron Hu (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (SPARK-21322) support histogram in filter cardinality estimation
Date Tue, 21 Nov 2017 01:44:00 GMT

    [ https://issues.apache.org/jira/browse/SPARK-21322?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16258601#comment-16258601
] 

Ron Hu edited comment on SPARK-21322 at 11/21/17 1:43 AM:
----------------------------------------------------------

Pull request 19357 was created while there were several dependencies that had not been merged
yet at that time. As a result, it has caused many conflicts. I decided to close pull request
19357 and start a clean one. Please review the new pull request 19783 instead.  Thanks.


was (Author: ron8hu):
Pull request 19357 was created while there were several dependencies that had not been defined
yet at that time. As a result, it has caused many conflicts. I decided to close pull request
19357 and start a clean one. Please review the new pull request 19783 instead.  Thanks.

> 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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