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Posted to issues@spark.apache.org by "Apache Spark (JIRA)" <ji...@apache.org> on 2016/01/25 09:15:39 UTC

[jira] [Commented] (SPARK-12978) Skip unnecessary final group-by when input data already clustered with group-by keys

    [ https://issues.apache.org/jira/browse/SPARK-12978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15114885#comment-15114885 ] 

Apache Spark commented on SPARK-12978:
--------------------------------------

User 'maropu' has created a pull request for this issue:
https://github.com/apache/spark/pull/10896

> Skip unnecessary final group-by when input data already clustered with group-by keys
> ------------------------------------------------------------------------------------
>
>                 Key: SPARK-12978
>                 URL: https://issues.apache.org/jira/browse/SPARK-12978
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 1.6.0
>            Reporter: Takeshi Yamamuro
>
> This ticket targets the optimization to skip an unnecessary group-by operation below;
> Without opt.:
> {code}
> == Physical Plan ==
> TungstenAggregate(key=[col0#159], functions=[(sum(col1#160),mode=Final,isDistinct=false),(avg(col2#161),mode=Final,isDistinct=false)], output=[col0#159,sum(col1)#177,avg(col2)#178])
> +- TungstenAggregate(key=[col0#159], functions=[(sum(col1#160),mode=Partial,isDistinct=false),(avg(col2#161),mode=Partial,isDistinct=false)], output=[col0#159,sum#200,sum#201,count#202L])
>    +- TungstenExchange hashpartitioning(col0#159,200), None
>       +- InMemoryColumnarTableScan [col0#159,col1#160,col2#161], InMemoryRelation [col0#159,col1#160,col2#161], true, 10000, StorageLevel(true, true, false, true, 1), ConvertToUnsafe, None
> {code}
> With opt.:
> {code}
> == Physical Plan ==
> TungstenAggregate(key=[col0#159], functions=[(sum(col1#160),mode=Complete,isDistinct=false),(avg(col2#161),mode=Final,isDistinct=false)], output=[col0#159,sum(col1)#177,avg(col2)#178])
> +- TungstenExchange hashpartitioning(col0#159,200), None
>   +- InMemoryColumnarTableScan [col0#159,col1#160,col2#161], InMemoryRelation [col0#159,col1#160,col2#161], true, 10000, StorageLevel(true, true, false, true, 1), ConvertToUnsafe, None
> {code}



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