[jira] [Commented] (HIVE-3421) Column Level Top K Values Statistics

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

    [ https://issues.apache.org/jira/browse/HIVE-3421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14106624#comment-14106624 ] 

wangmeng commented on HIVE-3421:
--------------------------------

this is very useful!!!  I  am  waiting  the  coming  version

> Column Level Top K Values Statistics
> ------------------------------------
>
>                 Key: HIVE-3421
>                 URL: https://issues.apache.org/jira/browse/HIVE-3421
>             Project: Hive
>          Issue Type: New Feature
>            Reporter: Feng Lu
>            Assignee: Feng Lu
>         Attachments: HIVE-3421.patch.1.txt, HIVE-3421.patch.2.txt, HIVE-3421.patch.3.txt, HIVE-3421.patch.4.txt, HIVE-3421.patch.5.txt, HIVE-3421.patch.6.txt, HIVE-3421.patch.7.txt, HIVE-3421.patch.8.txt, HIVE-3421.patch.9.txt, HIVE-3421.patch.txt
>
>
> Compute (estimate) top k values statistics for each column, and put the most skewed column into skewed info, if user hasn't specified skew.
> This feature depends on ListBucketing (create table skewed on) https://cwiki.apache.org/Hive/listbucketing.html.
> All column topk can be added to skewed info, if in the future skewed info supports multiple independent columns.
> The TopK algorithm is based on this paper:
> http://www.cs.ucsb.edu/research/tech_reports/reports/2005-23.pdf



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