Package org.apache.drill.exec.expr.fn.impl

Class StatisticsAggrFunctions.HllFieldReader

java.lang.Object

org.apache.drill.exec.expr.fn.impl.StatisticsAggrFunctions.HllFieldReader

All Implemented Interfaces:

DrillAggFunc, DrillFunc

Enclosing class:

StatisticsAggrFunctions

public static class StatisticsAggrFunctions.HllFieldReader
extends Object
implements DrillAggFunc

The log2m parameter defines the accuracy of the counter. The larger the log2m the better the accuracy. accuracy = 1.04/sqrt(2^log2m) where log2m - the number of bits to use as the basis for the HLL instance

Constructor Summary

Constructors

Constructor	Description
HllFieldReader()

Method Summary

Modifier and Type	Method	Description
void	add()
void	output()
void	reset()
void	setup()	Initialization for the beginning of the aggregation.

Methods inherited from class java.lang.Object

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

Constructor Details

HllFieldReader

public HllFieldReader()

Method Details

setup

public void setup()

Description copied from interface: DrillAggFunc

Initialization for the beginning of the aggregation.

Specified by:

setup in interface DrillAggFunc

add

public void add()

Specified by:

add in interface DrillAggFunc

output

public void output()

Specified by:

output in interface DrillAggFunc

reset

public void reset()

Specified by:

reset in interface DrillAggFunc