Package org.apache.hadoop.hbase.master.balancer

Class RegionCountSkewCostFunction

java.lang.Object

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

org.apache.hadoop.hbase.master.balancer.RegionCountSkewCostFunction

@Private
class RegionCountSkewCostFunction
extends CostFunction

Compute the cost of a potential cluster state from skew in number of regions on a cluster.

Field Summary

Fields

Modifier and Type	Field	Description
private final DoubleArrayCost	cost
(package private) static final float	DEFAULT_REGION_COUNT_SKEW_COST
(package private) static final String	REGION_COUNT_SKEW_COST_KEY

Fields inherited from class org.apache.hadoop.hbase.master.balancer.CostFunction

cluster, COST_EPSILON

Constructor Summary

Constructors

Constructor	Description
RegionCountSkewCostFunction(org.apache.hadoop.conf.Configuration conf)

Method Summary

Modifier and Type	Method	Description
protected double	cost()
(package private) void	prepare(BalancerClusterState cluster)	Called once per LB invocation to give the cost function to initialize it's state, and perform any costly calculation.
protected void	regionMoved(int region, int oldServer, int newServer)
final void	updateWeight(double[] weights)	Add the cost of this cost function to the weight of the candidate generator that is optimized for this cost function.

Methods inherited from class org.apache.hadoop.hbase.master.balancer.CostFunction

getMultiplier, isNeeded, postAction, scale, setMultiplier

Methods inherited from class java.lang.Object

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

Field Details

REGION_COUNT_SKEW_COST_KEY

static final String REGION_COUNT_SKEW_COST_KEY

See Also:

• Constant Field Values

DEFAULT_REGION_COUNT_SKEW_COST

static final float DEFAULT_REGION_COUNT_SKEW_COST

See Also:

• Constant Field Values

cost

private final DoubleArrayCost cost

Constructor Details

RegionCountSkewCostFunction

RegionCountSkewCostFunction(org.apache.hadoop.conf.Configuration conf)

Method Details

prepare

void prepare(BalancerClusterState cluster)

Description copied from class: CostFunction

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

Overrides:

prepare in class CostFunction

cost

protected double cost()

Specified by:

cost in class CostFunction

regionMoved

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

Overrides:

regionMoved in class CostFunction

updateWeight

public final void updateWeight(double[] weights)

Description copied from class: CostFunction

Add the cost of this cost function to the weight of the candidate generator that is optimized for this cost function. By default it is the RandomCandiateGenerator for a cost function. Called once per init or after postAction.

Overrides:

updateWeight in class CostFunction

Parameters:

weights - the weights for every generator.