org.apache.skywalking.apm.agent.core.sampling

Class SamplingService

java.lang.Object

org.apache.skywalking.apm.agent.core.sampling.SamplingService

All Implemented Interfaces:

BootService

public class SamplingService
extends Object
implements BootService

The SamplingService take charge of how to sample the TraceSegment. Every TraceSegments have been traced, but, considering CPU cost of serialization/deserialization, and network bandwidth, the agent do NOT send all of them to collector, if SAMPLING is on.

By default, SAMPLING is on, and Config.Agent#SAMPLE_N_PER_3_SECS

Author:

wusheng

Constructor Summary

Constructors

Constructor and Description
SamplingService()

Method Summary

Modifier and Type	Method and Description
void	boot()
void	forceSampled() Increase the sampling factor by force, to avoid sampling too many traces.
void	onComplete()
void	prepare()
void	shutdown()
boolean	trySampling()

Methods inherited from class java.lang.Object

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

Constructor Detail

SamplingService

public SamplingService()

Method Detail

prepare

public void prepare()
             throws Throwable

Specified by:

prepare in interface BootService

Throws:

Throwable

boot

public void boot()
          throws Throwable

Specified by:

boot in interface BootService

Throws:

Throwable

onComplete

public void onComplete()
                throws Throwable

Specified by:

onComplete in interface BootService

Throws:

Throwable

shutdown

public void shutdown()
              throws Throwable

Specified by:

shutdown in interface BootService

Throws:

Throwable

trySampling

public boolean trySampling()

Returns:

true, if sampling mechanism is on, and getDefault the sampling factor successfully.

forceSampled

public void forceSampled()

Increase the sampling factor by force, to avoid sampling too many traces. If many distributed traces require sampled, the trace beginning at local, has less chance to be sampled.