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  1. Crunch (Retired)
  2. CRUNCH-580

FileTargetImpl#handleOutputs Inefficiency on S3NativeFileSystem

Details

    • Bug
    • Status: Closed
    • Major
    • Resolution: Fixed
    • 0.13.0
    • 0.14.0
    • Core, IO
    • None
    • Amazon Elastic Map Reduce
    • Patch

    Description

      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.

      Attachments

        1. CRUNCH-580.patch
          8 kB
          Jeffrey Quinn
        2. CRUNCH-580.patch
          9 kB
          Jeffrey Quinn

        Activity

          People

            jwills Josh Wills
            jeffreyquinn Jeffrey Quinn
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              Updated:
              Resolved:

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