Hadoop Map/Reduce
  1. Hadoop Map/Reduce
  2. MAPREDUCE-2341

Map and Reduce task JVMs are hanging infinitely

    Details

    • Type: Bug Bug
    • Status: Open
    • Priority: Major Major
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: tasktracker
    • Labels:
      None
    • Environment:

      Linux

      Description

      Description:
      When launching Mapreduce application, the property mapred.job.reuse.jvm.num.tasks has been set to 0, as a result the task JVM(MAP or Reduce JVM) is hanging indefinitely and finally being killed by Tasktracker.

      Steps to Reproduce
      ------------------
      1) Set the mapred.job.reuse.jvm.num.tasks property in mapred-site.xml to 0
      2) Execute the wordcount example, child JVM is hanging indefinitely and finally killed by Tasktracker

        Activity

        Hide
        Bhallamudi Venkata Siva Kamesh added a comment -

        In the code segment(void org.apache.hadoop.mapred.Child.main(String[] args) throws Throwable), this case has been handled as shown below

        Child.java
           while(true) {
            ...................................................
            numTasksToExecute = job.getNumTasksToExecutePerJvm();
            assert(numTasksToExecute != 0);
            ...................................................
           }
         

        As assertions have not been enabled during runtime, the assertion statement here failed to assert and loop goes infinete.
        So I feel, we need to enable assertions while running HDFS/Mapreduce programs.

        Show
        Bhallamudi Venkata Siva Kamesh added a comment - In the code segment(void org.apache.hadoop.mapred.Child.main(String[] args) throws Throwable), this case has been handled as shown below Child.java while ( true ) { ................................................... numTasksToExecute = job.getNumTasksToExecutePerJvm(); assert (numTasksToExecute != 0); ................................................... } As assertions have not been enabled during runtime, the assertion statement here failed to assert and loop goes infinete. So I feel, we need to enable assertions while running HDFS/Mapreduce programs.

          People

          • Assignee:
            Unassigned
            Reporter:
            Bhallamudi Venkata Siva Kamesh
          • Votes:
            0 Vote for this issue
            Watchers:
            2 Start watching this issue

            Dates

            • Created:
              Updated:

              Development