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From "Gopal V (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-4639) Add has null flag to ORC internal index
Date Thu, 08 Jan 2015 06:27:34 GMT

    [ https://issues.apache.org/jira/browse/HIVE-4639?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14268884#comment-14268884
] 

Gopal V commented on HIVE-4639:
-------------------------------

Added this patch to my daily TPC-H 1Tb ETL & reloaded lineitem with the new format.

Testing {{select * from lineitem where l_shipdate is null;}}.

Before: 66.728 seconds (208774320430 bytes read)
After: 7.87 seconds  (539046900 bytes read)

LGTM - +1.

> Add has null flag to ORC internal index
> ---------------------------------------
>
>                 Key: HIVE-4639
>                 URL: https://issues.apache.org/jira/browse/HIVE-4639
>             Project: Hive
>          Issue Type: Improvement
>          Components: File Formats
>            Reporter: Owen O'Malley
>            Assignee: Prasanth Jayachandran
>         Attachments: HIVE-4639.1.patch, HIVE-4639.2.patch
>
>
> It would enable more predicate pushdown if we added a flag to the index entry recording
if there were any null values in the column for the 10k rows.



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