Hadoop HDFS
  1. Hadoop HDFS
  2. HDFS-2751

Datanode drops OS cache behind reads even for short reads

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major 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.

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

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            • Assignee:
              Todd Lipcon
              Reporter:
              Todd Lipcon
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              Dates

              • Created:
                Updated:
                Resolved:

                Development