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  1. Hadoop Common
  2. HADOOP-15292

Distcp's use of pread is slowing it down.

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: 2.5.0
    • Fix Version/s: 3.1.0
    • Component/s: tools/distcp
    • Labels:
      None
    • Target Version/s:

      Description

      Distcp currently uses positioned-reads (in RetriableFileCopyCommand#copyBytes) when the source offset is > 0. This results in unnecessary overheads (new BlockReader being created on the client-side, multiple readBlock() calls to the Datanodes, each of which requires the creation of a BlockSender and an inputstream to the ReplicaInfo).

        Attachments

        1. HADOOP-15292.000.patch
          4 kB
          Virajith Jalaparti
        2. HADOOP-15292.001.patch
          8 kB
          Virajith Jalaparti
        3. HADOOP-15292.002.patch
          8 kB
          Virajith Jalaparti

        Issue Links

        is related to

        Bug - A problem which impairs or prevents the functions of the product. HDFS-9146 HDFS forward seek() within a block shouldn't spawn new TCP Peer/RemoteBlockReader

        • Major - Major loss of function.
        • Open
        is required by

        Bug - A problem which impairs or prevents the functions of the product. HADOOP-16049 DistCp result has data and checksum mismatch when blocks per chunk > 0

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

        Improvement - An improvement or enhancement to an existing feature or task. HADOOP-15209 DistCp to eliminate needless deletion of files under already-deleted directories

        • Major - Major loss of function.
        • Resolved

        Improvement - An improvement or enhancement to an existing feature or task. MAPREDUCE-5899 Support incremental data copy in DistCp

        • Major - Major loss of function.
        • Closed

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            People

            • Assignee:
              virajith Virajith Jalaparti
              Reporter:
              virajith Virajith Jalaparti

              Dates

              • Created:
                Updated:
                Resolved:

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