zipkin.collector

Class CollectorSampler

java.lang.Object

zipkin.collector.CollectorSampler

public abstract class CollectorSampler
extends Object

CollectorSampler decides if a particular trace should be "sampled", i.e. recorded in permanent storage. This involves a consistent decision based on the span's trace ID with one notable exception: Debug spans are always stored.

Implementation

Accepts a percentage of trace ids by comparing their absolute value against a potentially dynamic boundary. eg isSampled == abs(traceId) <= boundary

While idempotent, this implementation's sample rate won't exactly match the input rate because trace ids are not perfectly distributed across 64bits. For example, tests have shown an error rate of 3% when 100K trace ids are random.

Field Summary

Fields

Modifier and Type	Field and Description
static CollectorSampler	ALWAYS_SAMPLE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CollectorSampler()

Method Summary

Modifier and Type	Method and Description
protected abstract long	boundary()
static CollectorSampler	create(float rate)
boolean	isSampled(Span span) Returns true if the span should be recorded to storage.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

ALWAYS_SAMPLE

public static final CollectorSampler ALWAYS_SAMPLE

Constructor Detail

CollectorSampler

protected CollectorSampler()

Method Detail

create

public static CollectorSampler create(float rate)

Parameters:

rate - minimum sample rate is 0.0001, or 0.01% of traces

boundary

protected abstract long boundary()

isSampled

public boolean isSampled(Span span)

Returns true if the span should be recorded to storage.

Zipkin v1 allows storage-layer sampling, which can help prevent spikes in traffic from overloading the system. Debug spans are always stored.

toString

public String toString()

Overrides:

toString in class Object