Hadoop HDFS
  1. Hadoop HDFS
  2. HDFS-1907

BlockMissingException upon concurrent read and write: reader was doing file position read while writer is doing write without hflush


    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 0.23.0
    • Fix Version/s: 0.23.0
    • Component/s: hdfs-client
    • Labels:
    • Environment:

      Run on a real cluster. Using the latest 0.23 build.

    • Hadoop Flags:


      BlockMissingException is thrown under this test scenario:
      Two different processes doing concurrent file r/w: one read and the other write on the same file

      • writer keep doing file write
      • reader doing position file read from beginning of the file to the visible end of file, repeatedly

      The reader is basically doing:
      byteRead = in.read(currentPosition, buffer, 0, byteToReadThisRound);
      where CurrentPostion=0, buffer is a byte array buffer, byteToReadThisRound = 1024*10000;

      Usually it does not fail right away. I have to read, close file, re-open the same file a few times to create the problem. I'll pose a test program to repro this problem after I've cleaned up a bit my current test program.

      1. HDFS-1907.patch
        1 kB
        John George
      2. HDFS-1907-2.patch
        3 kB
        John George
      3. HDFS-1907-3.patch
        3 kB
        John George
      4. HDFS-1907-4.patch
        2 kB
        John George
      5. HDFS-1907-5.patch
        2 kB
        John George
      6. HDFS-1907-5.patch
        2 kB
        John George

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            • Assignee:
              John George
              CW Chung
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