org.apache.hadoop.hbase.master.balancer

Class StochasticLoadBalancer.CostFunction

java.lang.Object

org.apache.hadoop.hbase.master.balancer.StochasticLoadBalancer.CostFunction

Direct Known Subclasses:

StochasticLoadBalancer.CostFromRegionLoadFunction, StochasticLoadBalancer.LocalityCostFunction, StochasticLoadBalancer.MoveCostFunction, StochasticLoadBalancer.RegionCountSkewCostFunction, StochasticLoadBalancer.TableSkewCostFunction

Enclosing class:

StochasticLoadBalancer

public abstract static class StochasticLoadBalancer.CostFunction
extends Object

Base class of StochasticLoadBalancer's Cost Functions.

Method Summary

Methods

Modifier and Type	Method and Description
protected double	costFromArray(double[] stats) Function to compute a scaled cost using DescriptiveStatistics.
protected double	scale(double min, double max, double value) Scale the value between 0 and 1.

Methods inherited from class java.lang.Object

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

Method Detail

costFromArray

protected double costFromArray(double[] stats)

Function to compute a scaled cost using DescriptiveStatistics. It assumes that this is a zero sum set of costs. It assumes that the worst case possible is all of the elements in one region server and the rest having 0.

Parameters:

stats - the costs

Returns:

a scaled set of costs.

scale

protected double scale(double min,
           double max,
           double value)

Scale the value between 0 and 1.

Parameters:

min - Min value

max - The Max value

value - The value to be scaled.

Returns:

The scaled value.