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https://issues.apache.org/jira/browse/HIVE-18622?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16363824#comment-16363824
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Matt McCline commented on HIVE-18622:
-------------------------------------

[~sershe] I reworked the if (inputColVector.noNulls) THEN code all across the 
board to be consistent and to fully clear the isNull arrays in one instance and 
set noNulls to true as you pointed to.  I think this is a big improvement.

Still have more work on the review comments.

> Vectorization: IF Statements, Comparisons, and more do not handle NULLs 
> correctly
> ---------------------------------------------------------------------------------
>
>                 Key: HIVE-18622
>                 URL: https://issues.apache.org/jira/browse/HIVE-18622
>             Project: Hive
>          Issue Type: Bug
>          Components: Hive
>            Reporter: Matt McCline
>            Assignee: Matt McCline
>            Priority: Critical
>             Fix For: 3.0.0
>
>         Attachments: HIVE-18622.03.patch, HIVE-18622.04.patch, 
> HIVE-18622.05.patch, HIVE-18622.06.patch, HIVE-18622.07.patch, 
> HIVE-18622.08.patch, HIVE-18622.09.patch, HIVE-18622.091.patch, 
> HIVE-18622.092.patch, HIVE-18622.093.patch, HIVE-18622.094.patch, 
> HIVE-18622.095.patch, HIVE-18622.096.patch, HIVE-18622.097.patch
>
>
>  
>  Many vector expression classes are setting noNulls to true which does not 
> work if the VRB is a scratch column being reused. The previous use may have 
> set noNulls to false and the isNull array will have some rows marked as NULL. 
> The result is wrong query results and sometimes NPEs (for BytesColumnVector).
> So, many vector expressions need this:
> {code:java}
>       // Carefully handle NULLs...
>       /*
>        * For better performance on LONG/DOUBLE we don't want the conditional
>        * statements inside the for loop.
>        */
>       outputColVector.noNulls = false;
>  {code}
> And, vector expressions need to make sure the isNull array entry is set when 
> outputColVector.noNulls is false.
> And, all place that assign column value need to set noNulls to false when the 
> value is NULL.
> Almost all cases where noNulls is set to true are incorrect.



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