• Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.7.0
    • Component/s: Query Processor
    • Labels:
    • Hadoop Flags:


      Concurrency model for Hive:

      Currently, hive does not provide a good concurrency model. The only guanrantee provided in case of concurrent readers and writers is that
      reader will not see partial data from the old version (before the write) and partial data from the new version (after the write).
      This has come across as a big problem, specially for background processes performing maintenance operations.

      The following possible solutions come to mind.

      1. Locks: Acquire read/write locks - they can be acquired at the beginning of the query or the write locks can be delayed till move
      task (when the directory is actually moved). Care needs to be taken for deadlocks.

      2. Versioning: The writer can create a new version if the current version is being read. Note that, it is not equivalent to snapshots,
      the old version can only be accessed by the current readers, and will be deleted when all of them have finished.



        1. hive.1293.9.patch
          122 kB
          Namit Jain
        2. hive.1293.8.patch
          121 kB
          Namit Jain
        3. hive.1293.7.patch
          122 kB
          Namit Jain
        4. hive.1293.6.patch
          117 kB
          Namit Jain
        5. hive.1293.5.patch
          101 kB
          Namit Jain
        6. hive.1293.4.patch
          100 kB
          Namit Jain
        7. hive.1293.3.patch
          99 kB
          Namit Jain
        8. hive.1293.2.patch
          89 kB
          Namit Jain
        9. hive_leases.txt
          3 kB
          Prasad Chakka
        10. hive.1293.1.patch
          87 kB
          Namit Jain

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              • Assignee:
                namit Namit Jain
                namit Namit Jain
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