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From "Aaron Davidson (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (SPARK-983) Support external sorting for RDD#sortByKey()
Date Thu, 22 May 2014 18:29:01 GMT

     [ https://issues.apache.org/jira/browse/SPARK-983?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Aaron Davidson updated SPARK-983:
---------------------------------

    Description: Currently, RDD#sortByKey() is implemented by a mapPartitions which creates
a buffer to hold the entire partition, then sorts it. This will cause an OOM if an entire
partition cannot fit in memory, which is especially problematic for skewed data. Rather than
OOMing, the behavior should be similar to the [ExternalAppendOnlyMap|https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala],
where we fallback to disk if we detect memory pressure.

> Support external sorting for RDD#sortByKey()
> --------------------------------------------
>
>                 Key: SPARK-983
>                 URL: https://issues.apache.org/jira/browse/SPARK-983
>             Project: Spark
>          Issue Type: New Feature
>    Affects Versions: 0.9.0
>            Reporter: Reynold Xin
>            Assignee: Aaron Davidson
>
> Currently, RDD#sortByKey() is implemented by a mapPartitions which creates a buffer to
hold the entire partition, then sorts it. This will cause an OOM if an entire partition cannot
fit in memory, which is especially problematic for skewed data. Rather than OOMing, the behavior
should be similar to the [ExternalAppendOnlyMap|https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala],
where we fallback to disk if we detect memory pressure.



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