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  1. Hadoop Common
  2. HADOOP-1970

tasktracker hang in reduce. Deadlock between main and comm thread

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Details

    • Bug
    • Status: Resolved
    • Blocker
    • Resolution: Fixed
    • 0.14.1
    • 0.14.2
    • None
    • None

    Description

      Saw one reduce task stuck on copy.
      jstack on the reduce task(task_200709272248_0001_r_000150_0) process showed

       
      Found one Java-level deadlock:
      =============================
      "Comm thread for task_200709272248_0001_r_000150_0":
        waiting to lock monitor 0x08144020 (object 0xd4e30aa8, a org.apache.hadoop.util.Progress),
        which is held by "main"
      "main":
        waiting to lock monitor 0x08144084 (object 0xd4e30958, a org.apache.hadoop.util.Progress),
        which is held by "Comm thread for task_200709272248_0001_r_000150_0"
      
      Java stack information for the threads listed above:
      ===================================================
      "Comm thread for task_200709272248_0001_r_000150_0":
              at org.apache.hadoop.util.Progress.toString(Progress.java:113)
              - waiting to lock <0xd4e30aa8> (a org.apache.hadoop.util.Progress)
              at org.apache.hadoop.util.Progress.toString(Progress.java:116)
              - locked <0xd4e30958> (a org.apache.hadoop.util.Progress)
              at org.apache.hadoop.util.Progress.toString(Progress.java:108)
              at org.apache.hadoop.mapred.Task$1.run(Task.java:268)
              at java.lang.Thread.run(Thread.java:619)
      "main":
              at org.apache.hadoop.util.Progress.startNextPhase(Progress.java:58)
              - waiting to lock <0xd4e30958> (a org.apache.hadoop.util.Progress)
              at org.apache.hadoop.util.Progress.complete(Progress.java:70)
              - locked <0xd4e30aa8> (a org.apache.hadoop.util.Progress)
              at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:253)
              at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java:1777)
      

      Attachments

        1. 1970_patch01
          4 kB
          Vivek Ratan
        2. 1970_patch02
          1 kB
          Vivek Ratan

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            vivekr Vivek Ratan
            knoguchi Koji Noguchi
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            Dates

              Created:
              Updated:
              Resolved: