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Posted to issues@calcite.apache.org by "Vladimir Sitnikov (JIRA)" <ji...@apache.org> on 2018/11/05 14:59:00 UTC
[jira] [Commented] (CALCITE-2605) NullPointerException when left
outer join implemented with EnumerableCorrelate
[ https://issues.apache.org/jira/browse/CALCITE-2605?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16675279#comment-16675279 ]
Vladimir Sitnikov commented on CALCITE-2605:
--------------------------------------------
If no objections, I'm going to commit https://github.com/apache/calcite/pull/901
> NullPointerException when left outer join implemented with EnumerableCorrelate
> ------------------------------------------------------------------------------
>
> Key: CALCITE-2605
> URL: https://issues.apache.org/jira/browse/CALCITE-2605
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.17.0
> Reporter: Ruben Quesada Lopez
> Assignee: Julian Hyde
> Priority: Major
> Fix For: 1.18.0
>
>
> In the context of a LEFT OUTER JOIN implemented via EnumerableCorrelate, the generated code for the selector does not check if the right object is null (which can be, since it is a LEFT join). This situation can lead to a NullPointerException.
> The root cause is located in EnumerableCorrelate::implement method, which builds the selector expression using a ternary operator whose "if" and "else" statements are switched:
> {code:java}
> Expression selector =
> EnumUtils.joinSelector(
> joinType.returnsJustFirstInput() ? joinType.toJoinType()
> : JoinRelType.INNER, physType,
> ImmutableList.of(leftResult.physType, rightResult.physType));
> {code}
> This code works (by coincidence) in the case of an INNER join; but in case of LEFT, it will incorrectly call EnumUtils.joinSelector(...) with JoinRelType.INNER instead of JoinRelType.LEFT, which will produce the problematic generated code. Also, the current code in the context of a SEMI or ANTI join will throw an IllegalStateException when calling SemiJoinType::toJoinType.
> If I am not mistaken, to fix this we just need to switch the ternary operator statements:
> {code:java}
> Expression selector =
> EnumUtils.joinSelector(
> joinType.returnsJustFirstInput() ? JoinRelType.INNER
> : joinType.toJoinType(), physType,
> ImmutableList.of(leftResult.physType, rightResult.physType));
> {code}
>
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