Uploaded image for project: 'Hadoop Common'
  1. Hadoop Common
  2. HADOOP-3155

reducers stuck at shuffling

    XMLWordPrintableJSON

Details

    • Bug
    • Status: Closed
    • Blocker
    • Resolution: Fixed
    • None
    • 0.19.0
    • None
    • None

    Description

      This happened with hadoop-0.16.2:

      In relatively small job (a few hundreds of mappers and reducers), reducers were stuck at shuffling.
      I saw the lines like the following repeated hundreds of thousands of times over a few hours:

      2008-04-02 17:17:44,640 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:44,641 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:46,643 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:48,645 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:50,647 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:52,649 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:52,650 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:54,651 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:54,652 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:56,654 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:17:58,656 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:00,658 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:02,660 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:02,661 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:04,662 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:04,663 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:06,664 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:06,665 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:08,667 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:10,669 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:12,671 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:14,673 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:14,674 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:16,675 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:16,676 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:18,678 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...
      2008-04-02 17:18:20,680 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Scheduled 0 of 0 known outputs (0 slow hosts and 0 dup hosts)
      2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Need 2 map output(s)
      2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0: Got 0 new map-outputs & 0 obsolete map-outputs from tasktracker and 0 map-outputs from previous failures
      2008-04-02 17:18:22,682 INFO org.apache.hadoop.mapred.ReduceTask: task_200804021200_0337_r_000008_0 Got 0 known map output location(s); scheduling...

      Attachments

        1. task_200807311630_0007_r_000006_0.syslog.gz
          205 kB
          Rick Cox
        2. patch-3155-debug-0.17.txt
          0.9 kB
          Amareshwari Sriramadasu
        3. patch-3155-debug-0.16.txt
          0.9 kB
          Amareshwari Sriramadasu
        4. jobevents_1007.txt
          1.48 MB
          Joydeep Sen Sarma
        5. hadoop-3155-logs.tar.gz
          4.28 MB
          Rick Cox
        6. HADOOP-3155-branch18.patch
          2 kB
          Aaron Kimball
        7. fetcherThread.patch
          0.6 kB
          Dhruba Borthakur
        8. fetcherThread.patch
          3 kB
          Dhruba Borthakur
        9. fetcherThread.patch
          1 kB
          Dhruba Borthakur
        10. fetcherThread.patch
          1 kB
          Dhruba Borthakur
        11. fetcherThread.patch
          1 kB
          Dhruba Borthakur
        12. events-job_200807311630_0007.txt
          128 kB
          Rick Cox

        Issue Links

          is related to

          Bug - A problem which impairs or prevents the functions of the product. HADOOP-3915 reducers hang, jobtracker loosing completely track of them.

          • Major - Major loss of function.
          • Resolved

          Activity

            People

              dhruba Dhruba Borthakur
              runping Runping Qi
              Votes:
              3 Vote for this issue
              Watchers:
              8 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved: