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  1. Hadoop HDFS
  2. HDFS-2751

Datanode drops OS cache behind reads even for short reads

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.23.0, 2.0.0-alpha
    • Fix Version/s: 0.23.1, 1.1.0
    • Component/s: datanode
    • Labels:
      None
    • Target Version/s:
    • Hadoop Flags:
      Reviewed

      Description

      HDFS-2465 has some code which attempts to disable the "drop cache behind reads" functionality when the reads are <256KB (eg HBase random access). But this check was missing in the close() function, so it always drops cache behind reads regardless of the size of the read. This hurts HBase random read performance when this patch is enabled.

        Attachments

        1. HDFS-2751.branch-1.patch
          0.7 kB
          Brandon Li
        2. hdfs-2751.txt
          0.8 kB
          Todd Lipcon
        3. hdfs-2751.txt
          0.8 kB
          Todd Lipcon

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              • Assignee:
                tlipcon Todd Lipcon
                Reporter:
                tlipcon Todd Lipcon
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                Dates

                • Created:
                  Updated:
                  Resolved: