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From "Rohini Palaniswamy (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-7215) Support predicate pushdown for null checks in ORCFile
Date Thu, 12 Jun 2014 18:47:02 GMT

    [ https://issues.apache.org/jira/browse/HIVE-7215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14029592#comment-14029592
] 

Rohini Palaniswamy commented on HIVE-7215:
------------------------------------------

bq. However, ORC reads the row group even in the opposite case, the case where there are no
nulls in column within the row group. 
   That is what my concern was. This amounts to no predicate pushdown as it is going to read
all row groups irrespective of whether there are nulls. So will leave this jira open to address
that. 

bq. if col is completely null in a row group, ORC predicate pushdown evaluates to true (based
on null statistics) and reads the row group.
   If there is a non null check, will the row group which has all nulls be ignored?

> Support predicate pushdown for null checks in ORCFile
> -----------------------------------------------------
>
>                 Key: HIVE-7215
>                 URL: https://issues.apache.org/jira/browse/HIVE-7215
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Rohini Palaniswamy
>
> Came across this missing feature during discussion of PIG-3760.



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