org.apache.hadoop.metrics2.lib

Class MetricMutableQuantiles

java.lang.Object

org.apache.hadoop.metrics2.lib.MutableMetric

org.apache.hadoop.metrics2.lib.MetricMutableQuantiles

All Implemented Interfaces:

MetricHistogram

@InterfaceAudience.Private
public class MetricMutableQuantiles
extends org.apache.hadoop.metrics2.lib.MutableMetric
implements MetricHistogram

Watches a stream of long values, maintaining online estimates of specific quantiles with provably low error bounds. This is particularly useful for accurate high-percentile (e.g. 95th, 99th) latency metrics.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<MetricQuantile,Long>	previousSnapshot

Fields inherited from interface org.apache.hadoop.metrics2.MetricHistogram

MAX_METRIC_NAME, MEAN_METRIC_NAME, MEDIAN_METRIC_NAME, MIN_METRIC_NAME, NINETY_FIFTH_PERCENTILE_METRIC_NAME, NINETY_NINETH_PERCENTILE_METRIC_NAME, NUM_OPS_METRIC_NAME, SEVENTY_FIFTH_PERCENTILE_METRIC_NAME

Constructor Summary

Constructors

Constructor and Description
MetricMutableQuantiles(String name, String description, String sampleName, String valueName, int interval) Instantiates a new MetricMutableQuantiles for a metric that rolls itself over on the specified time interval.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(long value) Add a single value to a histogram's stream of values.
int	getInterval()
void	snapshot(org.apache.hadoop.metrics2.MetricsRecordBuilder builder, boolean all)

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, toString, wait, wait, wait

Field Detail

previousSnapshot

protected Map<MetricQuantile,Long> previousSnapshot

Constructor Detail

MetricMutableQuantiles

public MetricMutableQuantiles(String name,
                      String description,
                      String sampleName,
                      String valueName,
                      int interval)

Instantiates a new MetricMutableQuantiles for a metric that rolls itself over on the specified time interval.

Parameters:

name - of the metric

description - long-form textual description of the metric

sampleName - type of items in the stream (e.g., "Ops")

valueName - type of the values

interval - rollover interval (in seconds) of the estimator

Method Detail

snapshot

public void snapshot(org.apache.hadoop.metrics2.MetricsRecordBuilder builder,
            boolean all)

Specified by:

snapshot in class org.apache.hadoop.metrics2.lib.MutableMetric

add

public void add(long value)

Description copied from interface: MetricHistogram

Add a single value to a histogram's stream of values.

Specified by:

add in interface MetricHistogram

getInterval

public int getInterval()