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  1. Hadoop Map/Reduce
  2. MAPREDUCE-5368

Save memory by set capacity, load factor and concurrency level for ConcurrentHashMap in TaskInProgress

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.2.0
    • Fix Version/s: 1.2.1
    • Component/s: mrv1
    • Labels:
      None

      Description

      Below is histo from our JobTracker:

      num #instances #bytes class name
      ----------------------------------------------
      1: 136048824 11347237456 [C
      2: 124156992 5959535616 java.util.concurrent.locks.ReentrantLock$NonfairSync
      3: 124156973 5959534704 java.util.concurrent.ConcurrentHashMap$Segment
      4: 135887753 5435510120 java.lang.String
      5: 124213692 3975044400 [Ljava.util.concurrent.ConcurrentHashMap$HashEntry;
      6: 63777311 3061310928 java.util.HashMap$Entry
      7: 35038252 2803060160 java.util.TreeMap
      8: 16921110 2712480072 [Ljava.util.HashMap$Entry;
      9: 4803617 2420449192 [Ljava.lang.Object;
      10: 50392816 2015712640 org.apache.hadoop.mapred.Counters$Counter
      11: 7775438 1181866576 [Ljava.util.concurrent.ConcurrentHashMap$Segment;
      12: 3882847 1118259936 org.apache.hadoop.mapred.TaskInProgress

      ConcurrentHashMap takes more than 14G(5959535616 + 5959534704 + 3975044400).
      The trouble maker are below codes in TaskInProgress.java:
      Map<TaskAttemptID, Locality> taskLocality =
      new ConcurrentHashMap<TaskAttemptID, Locality>();
      Map<TaskAttemptID, Avataar> taskAvataar =
      new ConcurrentHashMap<TaskAttemptID, Avataar>();

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            • Assignee:
              zhaoyunjiong yunjiong zhao
              Reporter:
              zhaoyunjiong yunjiong zhao
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              Dates

              • Created:
                Updated:
                Resolved: