org.apache.beam.sdk.util

Class HistogramData

java.lang.Object

org.apache.beam.sdk.util.HistogramData

All Implemented Interfaces:

java.io.Serializable

@Experimental
public class HistogramData
extends java.lang.Object
implements java.io.Serializable

A histogram that supports estimated percentile with linear interpolation.

We may consider using Apache Commons or HdrHistogram library in the future for advanced features such as sparsely populated histograms.

This class is considered experimental and may break or receive backwards-incompatible changes in future versions of the Apache Beam SDK.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	HistogramData.BucketType
static class	HistogramData.LinearBuckets

Constructor Summary

Constructors

Constructor and Description
HistogramData(HistogramData.BucketType bucketType) Create a histogram.

Method Summary

Modifier and Type	Method and Description
void	clear()
long	getCount(int bucketIndex) Get the bucket count for the given bucketIndex.
java.lang.String	getPercentileString(java.lang.String elemType, java.lang.String unit)
long	getTotalCount()
static HistogramData	linear(double start, double width, int numBuckets) Create a histogram with linear buckets.
double	p50()
double	p90()
double	p99()
void	record(double... values)
void	record(double value)

Methods inherited from class java.lang.Object

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

Constructor Detail

HistogramData

public HistogramData(HistogramData.BucketType bucketType)

Create a histogram.

Parameters:

bucketType - a bucket type for a new histogram instance.

Method Detail

linear

public static HistogramData linear(double start,
                                   double width,
                                   int numBuckets)

Create a histogram with linear buckets.

Parameters:

start - Lower bound of a starting bucket.

width - Bucket width. Smaller width implies a better resolution for percentile estimation.

numBuckets - The number of buckets. Upper bound of an ending bucket is defined by start + width * numBuckets.

Returns:

a new Histogram instance.

record

public void record(double... values)

clear

public void clear()

record

public void record(double value)

getTotalCount

public long getTotalCount()

getPercentileString

public java.lang.String getPercentileString(java.lang.String elemType,
                                            java.lang.String unit)

getCount

public long getCount(int bucketIndex)

Get the bucket count for the given bucketIndex.

This method does not guarantee the atomicity when sequentially accessing the multiple buckets i.e. other threads may alter the value between consecutive invocations. For summing the total number of elements in the histogram, use `getTotalCount()` instead.

Parameters:

bucketIndex - index of the bucket

Returns:

The number of elements in the specified bucket

p99

public double p99()

p90

public double p90()

p50

public double p50()