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From "Pradeep Kamath (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-963) Join in local mode matches null keys
Date Wed, 16 Sep 2009 18:51:57 GMT

    [ https://issues.apache.org/jira/browse/PIG-963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12756168#action_12756168
] 

Pradeep Kamath commented on PIG-963:
------------------------------------

This patch does not address the case where the join key is more than one column and hence
represented as a tuple. In this case if one of the key's value is null, join will still use
Tuple.compare() which will treat two null fields as equals. This is a known issue in map reduce
mode also and should be fixed for both map reduce and local mode through https://issues.apache.org/jira/browse/PIG-927

> Join in local mode matches null keys
> ------------------------------------
>
>                 Key: PIG-963
>                 URL: https://issues.apache.org/jira/browse/PIG-963
>             Project: Pig
>          Issue Type: Bug
>    Affects Versions: 0.4.0
>            Reporter: Pradeep Kamath
>            Assignee: Pradeep Kamath
>         Attachments: PIG-963-2.patch, PIG-963.patch
>
>
> Semantics of join and cogroup dictate that null values for the keys from different inputs
are NOT supposed to match. This is true in map reduce mode but local mode incorrectly matches
these records.

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