com.sleepycat.je.utilint

Class LatencyPercentile

java.lang.Object

com.sleepycat.je.utilint.BaseStat<T>

com.sleepycat.je.utilint.MapStatComponent<Long,LatencyPercentile>

com.sleepycat.je.utilint.LatencyPercentile

All Implemented Interfaces:

Serializable

public class LatencyPercentile
extends MapStatComponent<Long,LatencyPercentile>

A long JE stat component that computes a percentile latency by tracking latency values in milliseconds. The percentile value represents the smallest latency value for which no more than the specified percentage of the observed values were strictly less than the value and at least the specified percentage of the values were less than or equal to that value. To save space, specific values are recorded only below a specified value, so all larger values are lumped together and reported as the maximum value. Returns zero if no values are observed.

This class was inspired by the somewhat different LatencyStat class.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LatencyPercentile(String name, float percentile, int maxTrackedLatencyMillis) Creates an instance of this class

Method Summary

Modifier and Type	Method and Description
void	add(LatencyPercentile other)
void	add(long latencyMillis) Records an operation that used the specified amount of time in milliseconds.
void	clear() Resets the statistic to its initial state.
LatencyPercentile	copy() Narrow the return type to the component type.
Long	get() Calculates and returns the current value without clearing the existing statistics.
protected String	getFormattedValue(boolean useCommas) Returns the value of the statistic as a formatted string, either using or not using commas as requested.
boolean	isNotSet() Returns whether the statistic is in its initial state.
void	negate()
String	toString()
void	updateInterval(LatencyPercentile other) Updates the operation counts in this instance to represent the difference between the values stored in this instance and the ones in the argument.

Methods inherited from class com.sleepycat.je.utilint.MapStatComponent

getFormattedValue

Methods inherited from class java.lang.Object

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

Constructor Detail

LatencyPercentile

public LatencyPercentile(String name,
                         float percentile,
                         int maxTrackedLatencyMillis)

Creates an instance of this class

Parameters:

name - the name of the statistic

percentile - the percentile latency to report as a ratio between 0.0 and 1.0

maxTrackedLatencyMillis - the maximum for tracking latency values

Throws:

IllegalArgumentException - if the percentile is less than 0.0 or greater than 1.0, or if maxTrackedLatencyMillis is less than 0

Method Detail

getFormattedValue

protected String getFormattedValue(boolean useCommas)

Description copied from class: MapStatComponent

Returns the value of the statistic as a formatted string, either using or not using commas as requested. Implementations should make sure that the result does not contain commas when useCommas is false, because the value will be used in a comma-separated value file, where embedded commas would cause problems.

Specified by:

getFormattedValue in class MapStatComponent<Long,LatencyPercentile>

Parameters:

useCommas - whether to use commas

Returns:

the value as a formatted string

copy

public LatencyPercentile copy()

Description copied from class: MapStatComponent

Narrow the return type to the component type.

Specified by:

copy in class MapStatComponent<Long,LatencyPercentile>

Returns:

a copy

get

public Long get()

Calculates and returns the current value without clearing the existing statistics.

Specified by:

get in class BaseStat<Long>

Returns:

the value

clear

public void clear()

Description copied from class: BaseStat

Resets the statistic to its initial state.

Specified by:

clear in class BaseStat<Long>

isNotSet

public boolean isNotSet()

Description copied from class: BaseStat

Returns whether the statistic is in its initial state.

Specified by:

isNotSet in class BaseStat<Long>

Returns:

if the statistic is in its initial state

toString

public String toString()

Overrides:

toString in class Object

add

public void add(long latencyMillis)

Records an operation that used the specified amount of time in milliseconds.

add

public void add(LatencyPercentile other)

negate

public void negate()

updateInterval

public void updateInterval(LatencyPercentile other)

Updates the operation counts in this instance to represent the difference between the values stored in this instance and the ones in the argument.