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From "Peter Romianowski (JIRA)" <j...@apache.org>
Subject [jira] Created: (MAPREDUCE-1305) Massive performance problem with DistCp and -delete
Date Wed, 16 Dec 2009 22:34:18 GMT
Massive performance problem with DistCp and -delete
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                 Key: MAPREDUCE-1305
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1305
             Project: Hadoop Map/Reduce
          Issue Type: Improvement
          Components: distcp
    Affects Versions: 0.20.1
            Reporter: Peter Romianowski
            Assignee: Peter Romianowski


*First problem*

In org.apache.hadoop.tools.DistCp#deleteNonexisting we serialize FileStatus objects when the
path is all we need.

The performance problem comes from org.apache.hadoop.fs.RawLocalFileSystem.RawLocalFileStatus#write
which tries to retrieve file permissions by issuing a "ls -ld <path>" which is painfully
slow.

Changed that to just serialize Path and not FileStatus.

*Second problem*

To delete the files we invoke the "hadoop" command line tool with option "-rmr <path>".
Again, for each file.

Changed that to dstfs.delete(path, true)

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