org.apache.hadoop.metrics2.lib

Class MutableQuantiles

java.lang.Object

org.apache.hadoop.metrics2.lib.MutableMetric

org.apache.hadoop.metrics2.lib.MutableQuantiles

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public class MutableQuantiles
extends MutableMetric

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<org.apache.hadoop.metrics2.util.Quantile,Long>	previousSnapshot
static org.apache.hadoop.metrics2.util.Quantile[]	quantiles

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
void	add(long value)
org.apache.hadoop.metrics2.util.QuantileEstimator	getEstimator() Get the quantile estimator.
int	getInterval()
void	setEstimator(org.apache.hadoop.metrics2.util.QuantileEstimator quantileEstimator)
void	snapshot(MetricsRecordBuilder builder, boolean all) Get a snapshot of the metric
void	stop()

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

quantiles

public static final org.apache.hadoop.metrics2.util.Quantile[] quantiles

previousSnapshot

protected Map<org.apache.hadoop.metrics2.util.Quantile,Long> previousSnapshot

Constructor Detail

MutableQuantiles

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

Instantiates a new MutableQuantiles 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(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

add

public void add(long value)

getInterval

public int getInterval()

stop

public void stop()

getEstimator

public org.apache.hadoop.metrics2.util.QuantileEstimator getEstimator()

Get the quantile estimator.

Returns:

the quantile estimator

setEstimator

public void setEstimator(org.apache.hadoop.metrics2.util.QuantileEstimator quantileEstimator)