Package org.apache.hadoop.metrics2.lib

Class MutableStat

java.lang.Object
org.apache.hadoop.metrics2.lib.MutableMetric
org.apache.hadoop.metrics2.lib.MutableStat
Direct Known Subclasses:
MutableRate
@Public @Evolving public class MutableStat extends MutableMetric
A mutable metric with stats. Useful for keeping throughput/latency stats.

  • Constructor Summary

    Constructors
    Constructor
    Description
    MutableStat(String name, String description, String sampleName, String valueName)
    Construct a snapshot stat metric with extended stat off by default
    MutableStat(String name, String description, String sampleName, String valueName, boolean extended)
    Construct a sample statistics metric

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(long value)
    Add a snapshot to the metric.
    void
    add(long numSamples, long sum)
    Add a number of samples and their sum to the running stat Note that although use of this method will preserve accurate mean values, large values for numSamples may result in inaccurate variance values due to the use of a single step of the Welford method for variance calculation.
    long
    getSnapshotTimeStamp()
     
    org.apache.hadoop.metrics2.util.SampleStat
    lastStat()
    Return a SampleStat object that supports calls like StdDev and Mean.
    void
    resetMinMax()
    Reset the all time min max of the metric
    void
    setExtended(boolean extended)
    Set whether to display the extended stats (stdev, min/max etc.) or not
    void
    setUpdateTimeStamp(boolean updateTimeStamp)
    Set whether to update the snapshot time or not.
    void
    snapshot(MetricsRecordBuilder builder, boolean all)
    Get a snapshot of the metric
    String
    toString()
     

    Methods inherited from class org.apache.hadoop.metrics2.lib.MutableMetric

    changed, clearChanged, setChanged, snapshot

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • MutableStat

      public MutableStat(String name, String description, String sampleName, String valueName, boolean extended)
      Construct a sample statistics metric
      Parameters:
      name - of the metric
      description - of the metric
      sampleName - of the metric (e.g. "Ops")
      valueName - of the metric (e.g. "Time", "Latency")
      extended - create extended stats (stdev, min/max etc.) by default.

    • MutableStat

      public MutableStat(String name, String description, String sampleName, String valueName)
      Construct a snapshot stat metric with extended stat off by default
      Parameters:
      name - of the metric
      description - of the metric
      sampleName - of the metric (e.g. "Ops")
      valueName - of the metric (e.g. "Time", "Latency")

  • Method Details

    • setExtended

      public void setExtended(boolean extended)
      Set whether to display the extended stats (stdev, min/max etc.) or not
      Parameters:
      extended - enable/disable displaying extended stats

    • setUpdateTimeStamp

      public void setUpdateTimeStamp(boolean updateTimeStamp)
      Set whether to update the snapshot time or not.
      Parameters:
      updateTimeStamp - enable update stats snapshot timestamp

    • add

      public void add(long numSamples, long sum)
      Add a number of samples and their sum to the running stat Note that although use of this method will preserve accurate mean values, large values for numSamples may result in inaccurate variance values due to the use of a single step of the Welford method for variance calculation.
      Parameters:
      numSamples - number of samples
      sum - of the samples

    • add

      public void add(long value)
      Add a snapshot to the metric.
      Parameters:
      value - of the metric

    • snapshot

      public void snapshot(MetricsRecordBuilder builder, boolean all)
      Description copied from class: MutableMetric
      Get a snapshot of the metric
      Specified by:
      snapshot in class MutableMetric
      Parameters:
      builder - the metrics record builder
      all - if true, snapshot unchanged metrics as well

    • lastStat

      public org.apache.hadoop.metrics2.util.SampleStat lastStat()
      Return a SampleStat object that supports calls like StdDev and Mean.
      Returns:
      SampleStat

    • resetMinMax

      public void resetMinMax()
      Reset the all time min max of the metric

    • getSnapshotTimeStamp

      public long getSnapshotTimeStamp()
      Returns:
      Return the SampleStat snapshot timestamp.

    • toString

      public String toString()
      Overrides:
      toString in class Object