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Posted to issues@spark.apache.org by "Michael Armbrust (JIRA)" <ji...@apache.org> on 2014/08/20 23:05:27 UTC

[jira] [Updated] (SPARK-2554) CountDistinct and SumDistinct should do partial aggregation

     [ https://issues.apache.org/jira/browse/SPARK-2554?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Michael Armbrust updated SPARK-2554:
------------------------------------

            Priority: Blocker  (was: Major)
    Target Version/s: 1.1.0

> CountDistinct and SumDistinct should do partial aggregation
> -----------------------------------------------------------
>
>                 Key: SPARK-2554
>                 URL: https://issues.apache.org/jira/browse/SPARK-2554
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 1.0.1, 1.0.2
>            Reporter: Cheng Lian
>            Assignee: Michael Armbrust
>            Priority: Blocker
>
> {{CountDistinct}} and {{SumDistinct}} should first do a partial aggregation and return unique value sets in each partition as partial results. Shuffle IO can be greatly reduced in in cases that there are only a few unique values.



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