[jira] [Commented] (CALCITE-3667) EnumerableMergeJoin should not use take-while enumerator

["Julian Hyde (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3667?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17007787#comment-17007787 ] 

Julian Hyde commented on CALCITE-3667:
--------------------------------------

This change would change the complexity of the algorithm from {{O(m + n)}} to {{O(m * n)}}. Bad idea.

> EnumerableMergeJoin should not use  take-while enumerator
> ---------------------------------------------------------
>
>                 Key: CALCITE-3667
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3667
>             Project: Calcite
>          Issue Type: Improvement
>            Reporter: Jin Xing
>            Assignee: Jin Xing
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 40m
>  Remaining Estimate: 0h
>
> Currently EnumerableMergeJoin use take-while enumerator [1] to emit values satisfy predicate. However take-while enumerator stops the enumeration at once when predicate is failed, which is not correct and we should finish the enumeration and extract all the qualified  values.
> [1] https://github.com/apache/calcite/blob/master/linq4j/src/main/java/org/apache/calcite/linq4j/EnumerableDefaults.java#L3896



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