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From "Pengcheng Xiong (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-8681) CBO: Column names are missing from join expression in Map join with CBO enabled
Date Fri, 31 Oct 2014 04:20:35 GMT

     [ https://issues.apache.org/jira/browse/HIVE-8681?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Pengcheng Xiong updated HIVE-8681:
----------------------------------
    Attachment: HIVE-8681.1.patch

The basic idea to transform the internal name to external name is to
(1) use snapshotLogicalPlanForExplain() to make a snapshot of a logical plan after logical
optimization
(2) for each operator in the explain task, call the prepareCBOExplain function for each operatorDesc
(2.1) Each operator uses ''helpGetStartOp'' to map to a logical operator (start point) in
the LogicalPlan
(2.2) From start point, each operatorDesc uses ''findExternalName'' to track its external
name

> 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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