org.apache.hadoop.hbase.util

Class FastLongHistogram

java.lang.Object

org.apache.hadoop.hbase.util.FastLongHistogram

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public class FastLongHistogram
extends java.lang.Object

FastLongHistogram is a thread-safe class that estimate distribution of data and computes the quantiles.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_NBINS Default number of bins.
static double[]	DEFAULT_QUANTILES

Constructor Summary

Constructors

Constructor and Description
FastLongHistogram() Constructor.
FastLongHistogram(int numOfBins) Constructor.
FastLongHistogram(int numOfBins, long min, long max) Constructor setting the bins assuming a uniform distribution within a range.

Method Summary

Modifier and Type	Method and Description
void	add(long value, long count) Adds a value to the histogram.
long	getCount()
long	getMax()
long	getMean()
long	getMin()
long	getNumAtOrBelow(long value)
long[]	getQuantiles()
long[]	getQuantiles(double[] quantiles) Computes the quantiles give the ratios.
FastLongHistogram	reset() Resets the histogram for new counting.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_NBINS

public static final int DEFAULT_NBINS

Default number of bins.

See Also:

Constant Field Values

DEFAULT_QUANTILES

public static final double[] DEFAULT_QUANTILES

Constructor Detail

FastLongHistogram

public FastLongHistogram()

Constructor.

FastLongHistogram

public FastLongHistogram(int numOfBins)

Constructor.

Parameters:

numOfBins - the number of bins for the histogram. A larger value results in more precise results but with lower efficiency, and vice versus.

FastLongHistogram

public FastLongHistogram(int numOfBins,
                         long min,
                         long max)

Constructor setting the bins assuming a uniform distribution within a range.

Parameters:

numOfBins - the number of bins for the histogram. A larger value results in more precise results but with lower efficiency, and vice versus.

min - lower bound of the region, inclusive.

max - higher bound of the region, inclusive.

Method Detail

add

public void add(long value,
                long count)

Adds a value to the histogram.

getQuantiles

public long[] getQuantiles(double[] quantiles)

Computes the quantiles give the ratios.

getQuantiles

public long[] getQuantiles()

getMin

public long getMin()

getMax

public long getMax()

getCount

public long getCount()

getMean

public long getMean()

getNumAtOrBelow

public long getNumAtOrBelow(long value)

reset

public FastLongHistogram reset()

Resets the histogram for new counting.