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From "Pengcheng Xiong (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-8681) CBO: Column names are missing from join expression in Map join with CBO enabled
Date Fri, 31 Oct 2014 21:02:33 GMT

    [ https://issues.apache.org/jira/browse/HIVE-8681?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14192481#comment-14192481
] 

Pengcheng Xiong commented on HIVE-8681:
---------------------------------------

As per [~jpullokkaran]'s request, include [~vikram.dixit] in the discussion.

And, an important assumption here is that, every physical operator (SEL, RS, JOIN (include
hashtablesinkop, join, mapjoinop, mergejoinop, semijoin), FIL, GRY, FS, UNION) that is included
in the explain can find its corresponding logical operator. If it is not found, its internal
column names will be used.

> CBO: Column names are missing from join expression in Map join with CBO enabled
> -------------------------------------------------------------------------------
>
>                 Key: HIVE-8681
>                 URL: https://issues.apache.org/jira/browse/HIVE-8681
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Pengcheng Xiong
>            Assignee: Pengcheng Xiong
>         Attachments: HIVE-8681.1.patch
>
>
> On Hive 14 when CBO is enabled the column names are missing from the join expression.
Rather than to use external names "key", "value", some internal names such as "_col0" or "_col1"
are used. For map join with more than two tables it is very hard to figure the actual join
order. In this patch, I am going to address this issue not only for join but also for all
the other operators. And it will also be addressed in not only CLI but also TEZ environment.



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