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From "Chinna Rao Lalam (JIRA)" <j...@apache.org>
Subject [jira] [Assigned] (HIVE-8639) Convert SMBJoin to MapJoin [Spark Branch]
Date Fri, 31 Oct 2014 04:45:34 GMT

     [ https://issues.apache.org/jira/browse/HIVE-8639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Chinna Rao Lalam reassigned HIVE-8639:
--------------------------------------

    Assignee: Chinna Rao Lalam

> Convert SMBJoin to MapJoin [Spark Branch]
> -----------------------------------------
>
>                 Key: HIVE-8639
>                 URL: https://issues.apache.org/jira/browse/HIVE-8639
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Spark
>            Reporter: Szehon Ho
>            Assignee: Chinna Rao Lalam
>
> HIVE-8202 supports auto-conversion of SMB Join.  However, if the tables are partitioned,
there could be a slow down as each mapper would need to get a very small chunk of a partition
which has a single key. Thus, in some scenarios it's beneficial to convert SMB join to map
join.
> The task is to research and support the conversion from SMB join to map join for Spark
execution engine.  See the equivalent of MapReduce in SortMergeJoinResolver.



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