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From "Prasanth Jayachandran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-4639) Add has null flag to ORC internal index
Date Wed, 07 Jan 2015 19:45:34 GMT

    [ https://issues.apache.org/jira/browse/HIVE-4639?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14268099#comment-14268099
] 

Prasanth Jayachandran commented on HIVE-4639:
---------------------------------------------

As Gopal mentioned, we can infer the other stats from the existing information
all_nulls -> min = null
no_nulls -> hasNull = false
some_nulls -> hasNull = true, min != null

> 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
>
>
> 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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