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  1. Hadoop Common
  2. HADOOP-11694 Über-jira: S3a phase II: robustness, scale and performance
  3. HADOOP-13208

S3A listFiles(recursive=true) to do a bulk listObjects instead of walking the pseudo-tree of directories

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Details

    • Sub-task
    • Status: Resolved
    • Minor
    • Resolution: Fixed
    • None
    • 2.8.0, 3.0.0-alpha1
    • fs/s3
    • None
    • Reviewed
    • Hide
      S3A has optimized the listFiles method by doing a bulk listing of all entries under a path in a single S3 operation instead of recursively walking the directory tree. The listLocatedStatus method has been optimized by fetching results from S3 lazily as the caller traverses the returned iterator instead of doing an eager fetch of all possible results.
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      S3A has optimized the listFiles method by doing a bulk listing of all entries under a path in a single S3 operation instead of recursively walking the directory tree. The listLocatedStatus method has been optimized by fetching results from S3 lazily as the caller traverses the returned iterator instead of doing an eager fetch of all possible results.

    Description

      A major cost in split calculation against object stores turns out be listing the directory tree itself. That's because against S3, it takes S3A two HEADs and two lists to list the content of any directory path (2 HEADs + 1 list for getFileStatus(); the next list to query the contents).

      Listing a directory could be improved slightly by combining the final two listings. However, a listing of a directory tree will still be O(directories). In contrast, a recursive listFiles() operation should be implementable by a bulk listing of all descendant paths; one List operation per thousand descendants.

      As the result of this call is an iterator, the ongoing listing can be implemented within the iterator itself

      Attachments

        1. HADOOP-13208-branch-2-001.patch
          89 kB
          Steve Loughran
        2. HADOOP-13208-branch-2-007.patch
          90 kB
          Steve Loughran
        3. HADOOP-13208-branch-2-008.patch
          90 kB
          Steve Loughran
        4. HADOOP-13208-branch-2-009.patch
          105 kB
          Steve Loughran
        5. HADOOP-13208-branch-2-010.patch
          105 kB
          Steve Loughran
        6. HADOOP-13208-branch-2-011.patch
          112 kB
          Steve Loughran
        7. HADOOP-13208-branch-2-012.patch
          113 kB
          Steve Loughran
        8. HADOOP-13208-branch-2-017.patch
          165 kB
          Steve Loughran
        9. HADOOP-13208-branch-2-018.patch
          42 kB
          Steve Loughran
        10. HADOOP-13208-branch-2-019.patch
          43 kB
          Steve Loughran
        11. HADOOP-13208-branch-2-020.patch
          50 kB
          Steve Loughran
        12. HADOOP-13208-branch-2-021.patch
          50 kB
          Chris Nauroth

        Issue Links

          depends upon

          Sub-task - The sub-task of the issue HADOOP-13207 Specify FileSystem listStatus, listFiles and RemoteIterator

          • Major - Major loss of function.
          • Resolved
          is depended upon by

          Sub-task - The sub-task of the issue HADOOP-13371 S3A globber to use bulk listObject call over recursive directory scan

          • Major - Major loss of function.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. SPARK-17593 list files on s3 very slow

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Resolved
          is related to

          Sub-task - The sub-task of the issue HADOOP-14755 WASB to implement listFiles(Path f, boolean recursive) through flat list

          • Major - Major loss of function.
          • Resolved

          Sub-task - The sub-task of the issue HIVE-14165 Remove Hive file listing during split computation

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. SPARK-17593 list files on s3 very slow

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Resolved
          supercedes

          Improvement - An improvement or enhancement to an existing feature or task. HADOOP-15192 S3A listStatus excessively slow -hurts Spark job partitioning

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

          Activity

            People

              stevel@apache.org Steve Loughran
              stevel@apache.org Steve Loughran
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              Dates

                Created:
                Updated:
                Resolved:

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