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  1. Hadoop HDFS
  2. HDFS-4049

hflush performance regression due to nagling delays

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Details

    • Bug
    • Status: Closed
    • Critical
    • Resolution: Fixed
    • 2.0.2-alpha, 3.0.0-alpha1
    • 2.0.3-alpha
    • datanode, performance
    • None

    Description

      HDFS-3721 reworked the way that packets are mirrored through the pipeline in the datanode. This caused two write() calls where there used to be one, which interacts badly with nagling so that there are 40ms bubbles on hflush() calls. We didn't notice this in the tests because the hflush perf test only uses a single datanode.

      Attachments

        1. hdfs-4049.txt
          18 kB
          Todd Lipcon
        2. hdfs-4049.txt
          18 kB
          Todd Lipcon
        3. hdfs-4049.txt
          12 kB
          Todd Lipcon

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            tlipcon Todd Lipcon
            tlipcon Todd Lipcon
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            Dates

              Created:
              Updated:
              Resolved: