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From "Navis (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-5056) MapJoinProcessor ignores order of values in removing RS
Date Wed, 14 Aug 2013 01:05:48 GMT

    [ https://issues.apache.org/jira/browse/HIVE-5056?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13739106#comment-13739106
] 

Navis commented on HIVE-5056:
-----------------------------

{noformat}
RS := ReduceSinkOperator, JOIN := JoinOperator, RR := RowResolver

If there are 0:T1(a1,a2) and 1:T2(b1,b2) and JOIN has value expression like {0:[T1.a1,T2.a2],
1:[T2.b2,T2.b1]}, output of JOIN is like this.

output : expression 
 _col0 : T1.a1
 _col1 : T1.a2
 _col2 : T2.b2 (not b1)
 _col3 : T2.b1 (not b2)
{noformat}

MapJoinProcessor should remove RSs, which means column expressions(ExprNodeDescs) are not
valid and should be rebased on parent of RSs (because expressions should be based on RR of
parent). Previously, hive found columns by referencing RR of parents of RSs. In this case,
the order is something like [T1.a1-T2.a2-T2.b1-T2.b2], which results invalid column mapping
like this.

{noformat}
output : expression 
 _col0 : T1.a1
 _col1 : T1.a2
 _col2 : T2.b1
 _col3 : T2.b2
{noformat}
                
> MapJoinProcessor ignores order of values in removing RS
> -------------------------------------------------------
>
>                 Key: HIVE-5056
>                 URL: https://issues.apache.org/jira/browse/HIVE-5056
>             Project: Hive
>          Issue Type: Bug
>          Components: Query Processor
>            Reporter: Navis
>            Assignee: Navis
>         Attachments: HIVE-5056.D12147.1.patch, HIVE-5056.D12147.2.patch
>
>
> http://www.mail-archive.com/user@hive.apache.org/msg09073.html

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