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From "Prasanth J (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-5849) Improve the stats of operators based on heuristics in the absence of any column statistics
Date Wed, 20 Nov 2013 19:30:35 GMT

     [ https://issues.apache.org/jira/browse/HIVE-5849?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Prasanth J updated HIVE-5849:
-----------------------------

    Attachment: HIVE-5849.4.javaonly.patch

Uploading java only patch for review. Q file tests are running. I will reupload the patch
once done.

> 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
>
>
> 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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