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Posted to dev@hive.apache.org by "Harish Butani (JIRA)" <ji...@apache.org> on 2013/11/20 23:45:35 UTC

[jira] [Commented] (HIVE-5849) Improve the stats of operators based on heuristics in the absence of any column statistics

    [ https://issues.apache.org/jira/browse/HIVE-5849?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13828229#comment-13828229 ] 

Harish Butani commented on HIVE-5849:
-------------------------------------

+1

> Improve the stats of operators based on heuristics in the absence of any column statistics
> ------------------------------------------------------------------------------------------
>
>                 Key: HIVE-5849
>                 URL: https://issues.apache.org/jira/browse/HIVE-5849
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Query Processor, Statistics
>            Reporter: Prasanth J
>            Assignee: Prasanth J
>             Fix For: 0.13.0
>
>         Attachments: HIVE-5849.1.patch.txt, HIVE-5849.2.patch.txt, HIVE-5849.3.patch, HIVE-5849.3.patch.txt, HIVE-5849.4.javaonly.patch, HIVE-5849.5.patch
>
>
> In the absence of any column statistics, operators will simply use the statistics from its parents. It is useful to apply some heuristics to update basic statistics (number of rows and data size) in the absence of any column statistics. This will be worst case scenario.



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