[jira] [Commented] (DRILL-3477) Using IntVector for null expressions causes problems with implicit cast

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DRILL-3477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14619751#comment-14619751 ] 

ASF GitHub Bot commented on DRILL-3477:
---------------------------------------

GitHub user StevenMPhillips opened a pull request:

    https://github.com/apache/drill/pull/84

    DRILL-3477: Use varbinary for null vectors

    

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/StevenMPhillips/incubator-drill drill-3477

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/drill/pull/84.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #84
    
----
commit 5dc85777fa9826a9e72a428f9abfda1e8d066123
Author: Steven Phillips <sm...@apache.org>
Date:   2015-07-09T00:39:32Z

    DRILL-3477: Use varbinary for null vectors

----


> Using IntVector for null expressions causes problems with implicit cast
> -----------------------------------------------------------------------
>
>                 Key: DRILL-3477
>                 URL: https://issues.apache.org/jira/browse/DRILL-3477
>             Project: Apache Drill
>          Issue Type: Bug
>            Reporter: Steven Phillips
>            Assignee: Steven Phillips
>
> See DRILL-3353, for example.
> A simple example is this:
> {code}
> select * from t where a = 's';
> {code}
> If the first batch scanned from table t does not contain the column a, the expression materializer in Project defaults to Nullable Int as the type. The Filter then sees an Equals expression between a VarChar and an Int type, so it does an implicit cast. Implicit cast rules give Int higher precedence, so the literal 's' is cast to Int, which ends up throwing a NumberFormatException.
> In the class ResolverTypePrecedence, we see that Null type has the lowest precedence, which makes sense. But since we don't actually currently have an implementation for NullVector, we should materialize the Null type as the Vector with the lowest possible precedence, which is VarBinary.
> My suggestion is that we should use VarBinary as the default type in ExpressionMaterializer instead of Int.



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