Field Detail

• multiplier

  private float multiplier

• cluster

  protected BaseLoadBalancer.Cluster cluster

Constructor Detail

• StochasticLoadBalancer.CostFunction

  StochasticLoadBalancer.CostFunction(org.apache.hadoop.conf.Configuration c)

Method Detail

• getMultiplier

  float getMultiplier()

• setMultiplier

  void setMultiplier(float m)

• init

  void init(BaseLoadBalancer.Cluster cluster)

  Called once per LB invocation to give the cost function to initialize it's state, and perform any costly calculation.

• postAction

  void postAction(BaseLoadBalancer.Cluster.Action action)

  Called once per cluster Action to give the cost function an opportunity to update it's state. postAction() is always called at least once before cost() is called with the cluster that this action is performed on.

• regionMoved

  protected void regionMoved(int region,
                 int oldServer,
                 int newServer)

• cost

  abstract double cost()

• 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.

• getSum

  private double getSum(double[] stats)

• 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.