[jira] [Commented] (SPARK-5581) When writing sorted map output file, avoid open / close between each partition

["Sital Kedia (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-5581?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15184491#comment-15184491 ] 

Sital Kedia commented on SPARK-5581:
------------------------------------

Is anyone working on this issue? I would like to work on it, if not. We are seeing very bad map side performance when the number of partitions is too large because of this issue. 

> When writing sorted map output file, avoid open / close between each partition
> ------------------------------------------------------------------------------
>
>                 Key: SPARK-5581
>                 URL: https://issues.apache.org/jira/browse/SPARK-5581
>             Project: Spark
>          Issue Type: Improvement
>          Components: Shuffle
>    Affects Versions: 1.3.0
>            Reporter: Sandy Ryza
>
> {code}
>       // Bypassing merge-sort; get an iterator by partition and just write everything directly.
>       for ((id, elements) <- this.partitionedIterator) {
>         if (elements.hasNext) {
>           val writer = blockManager.getDiskWriter(
>             blockId, outputFile, ser, fileBufferSize, context.taskMetrics.shuffleWriteMetrics.get)
>           for (elem <- elements) {
>             writer.write(elem)
>           }
>           writer.commitAndClose()
>           val segment = writer.fileSegment()
>           lengths(id) = segment.length
>         }
>       }
> {code}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org