org.terracotta.statistics.derived.latency

Class MaximumLatencyHistory

java.lang.Object

org.terracotta.statistics.derived.latency.MaximumLatencyHistory

All Implemented Interfaces:

ChainedEventObserver, ChainedObserver, SampledStatistic<Long>, ValueStatistic<Long>

public class MaximumLatencyHistory
extends Object
implements ChainedEventObserver, SampledStatistic<Long>

Keeps a history of the maximum operation latencies over a specific window. The window needs to be as small as possible to get the most detailed history.

This is important to note that the history is based on a sample count and not a time frame. If you set a history to 100 samples and a window of 500ms, you won't have a complete time-frame of 10 seconds. You can have a sample at t0, then another one at t0 + 1 sec depending on when the operations occur.

Author:

Mathieu Carbou

Constructor Summary

Constructors

Constructor and Description
MaximumLatencyHistory(int historySize, long windowSize, TimeUnit windowSizeUnit, LongSupplier timeSupplier)
MaximumLatencyHistory(int historySize, long windowSize, TimeUnit windowSizeUnit, LongSupplier timeSupplier, Consumer<LatencyPeriodAccumulator> sink)

Method Summary

Modifier and Type	Method and Description
void	event(long timeNs, long latencyNs) Called to indicate an event happened.
List<Sample<Long>>	history() The history of values
List<Sample<Long>>	history(long sinceMillis) The history of values, since a given time in ms
StatisticType	type()
Long	value()

Methods inherited from class java.lang.Object

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

Constructor Detail

MaximumLatencyHistory

public MaximumLatencyHistory(int historySize,
                             long windowSize,
                             TimeUnit windowSizeUnit,
                             LongSupplier timeSupplier)

MaximumLatencyHistory

public MaximumLatencyHistory(int historySize,
                             long windowSize,
                             TimeUnit windowSizeUnit,
                             LongSupplier timeSupplier,
                             Consumer<LatencyPeriodAccumulator> sink)

Parameters:

historySize - The number of samples to keep

windowSize - The size of the window over which the reduction is applied. A small value is better for more details, but history might discard values faster.

windowSizeUnit - Window size unit

sink - The sink used to collect the old values that are discarded from the history.

Method Detail

event

public void event(long timeNs,
                  long latencyNs)

Description copied from interface: ChainedEventObserver

Called to indicate an event happened.

Specified by:

event in interface ChainedEventObserver

Parameters:

timeNs - the clock at event completion in ns

latencyNs - the event latency in ns

value

public Long value()

Specified by:

value in interface ValueStatistic<Long>

Returns:

The current statistic value

type

public StatisticType type()

Specified by:

type in interface ValueStatistic<Long>

Returns:

The statistic type

history

public List<Sample<Long>> history()

Description copied from interface: SampledStatistic

The history of values

Specified by:

history in interface SampledStatistic<Long>

Returns:

the list

history

public List<Sample<Long>> history(long sinceMillis)

Description copied from interface: SampledStatistic

The history of values, since a given time in ms

Specified by:

history in interface SampledStatistic<Long>

Parameters:

sinceMillis - starting point of history in ms

Returns:

the list