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  1. Hadoop HDFS
  2. HDFS-1093

Improve namenode scalability by splitting the FSNamesystem synchronized section in a read/write lock

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Details

    • Improvement
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 0.22.0
    • namenode
    • None
    • Reviewed

    Description

      Most critical data structures in the NameNode (NN) are protected by a syncronized methods in the FSNamesystem class. This essentially makes critical code paths in the NN single-threaded. However, a large percentage of the NN calls are listStatus, getBlockLocations, etc which do not change internal data structures at all, these are read-only calls. If we change the FSNamesystem lock to a read/write lock, many of the above operations can occur in parallel, thus improving the scalability of the NN.

      Attachments

        1. NNreadwriteLock_trunk_1.txt
          60 kB
          Dhruba Borthakur
        2. NNreadwriteLock_trunk_2.txt
          60 kB
          Suresh Srinivas
        3. NNreadwriteLock_trunk_3.txt
          63 kB
          Dhruba Borthakur
        4. NNreadwriteLock_trunk_4.txt
          65 kB
          Dhruba Borthakur
        5. NNreadwriteLock_trunk_5.txt
          64 kB
          Dhruba Borthakur
        6. NNreadwriteLock.txt
          53 kB
          Dhruba Borthakur

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              dhruba Dhruba Borthakur
              dhruba Dhruba Borthakur
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                Created:
                Updated:
                Resolved: