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https://issues.apache.org/jira/browse/CRUNCH-580?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jeffrey Quinn updated CRUNCH-580:
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Attachment: CRUNCH-580.patch
> FileTargetImpl#handleOutputs Inefficiency on S3NativeFileSystem
> ---------------------------------------------------------------
>
> Key: CRUNCH-580
> URL: https://issues.apache.org/jira/browse/CRUNCH-580
> Project: Crunch
> Issue Type: Bug
> Components: Core, IO
> Affects Versions: 0.13.0
> Environment: Amazon Elastic Map Reduce
> Reporter: Jeffrey Quinn
> Assignee: Josh Wills
> Attachments: CRUNCH-580.patch, CRUNCH-580.patch
>
>
> We have run in to a pretty frustrating inefficiency inside of
> org.apache.crunch.io.impl.FileTargetImpl#handleOutputs.
> This method loops over all of the partial output files and moves them to
> their ultimate destination directories, calling
> org.apache.hadoop.fs.FileSystem#rename(org.apache.hadoop.fs.Path,
> org.apache.hadoop.fs.Path) on each partial output in a loop.
> This is no problem when the org.apache.hadoop.fs.FileSystem in question is
> HDFS where #rename is a cheap operation, but when an implementation such as
> S3NativeFileSystem is used it is extremely inefficient, as each iteration
> through the loop makes a single blocking S3 API call, and this loop can be
> extremely long when there are many thousands of partial output files.
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