| Interface | Description | 
|---|---|
| MetricsBalancerSource | |
| MetricsStochasticBalancerSource | This interface extends the basic metrics balancer source to add a function
 to report metrics that related to stochastic load balancer. | 
| Class | Description | 
|---|---|
| BalancerChore | Chore that will call HMaster.balance HMaster.balance()when
 needed. | 
| BalancerRegionLoad | Wrapper class for the few fields required by the  StochasticLoadBalancerfrom the fullRegionMetrics. | 
| BaseLoadBalancer | The base class for load balancers. | 
| BaseLoadBalancer.Cluster | An efficient array based implementation similar to ClusterState for keeping
 the status of the cluster in terms of region assignment and distribution. | 
| BaseLoadBalancer.Cluster.Action | An action to move or swap a region | 
| BaseLoadBalancer.Cluster.AssignRegionAction | |
| BaseLoadBalancer.Cluster.MoveRegionAction | |
| BaseLoadBalancer.Cluster.SwapRegionsAction | |
| BaseLoadBalancer.DefaultRackManager | |
| CandidateGenerator | Generates a candidate action to be applied to the cluster for cost function search | 
| ClusterLoadState | Class used to hold the current state of the cluster and how balanced it is. | 
| ClusterStatusChore | Chore that will feed the balancer the cluster status. | 
| FavoredStochasticBalancer | An implementation of the  LoadBalancerthat
 assigns favored nodes for each region. | 
| HeterogeneousRegionCountCostFunction | This is an optional Cost function designed to allow region count skew across RegionServers. | 
| LoadBalancerFactory | The class that creates a load balancer from a conf. | 
| LoadCandidateGenerator | |
| LocalityBasedCandidateGenerator | |
| MetricsBalancer | Faced for exposing metrics about the balancer. | 
| MetricsBalancerSourceImpl | |
| MetricsStochasticBalancer | This metrics balancer uses extended source for stochastic load balancer
 to report its related metrics to JMX. | 
| MetricsStochasticBalancerSourceImpl | |
| RegionInfoComparator | The following comparator assumes that RegionId from HRegionInfo can represent
 the age of the region - larger RegionId means the region is younger. | 
| RegionLocationFinder | This will find where data for a region is located in HDFS. | 
| RegionReplicaCandidateGenerator | Generates candidates which moves the replicas out of the region server for
 co-hosted region replicas | 
| ServerAndLoad | Data structure that holds servername and 'load'. | 
| SimpleLoadBalancer | Makes decisions about the placement and movement of Regions across
 RegionServers. | 
| SimpleLoadBalancer.BalanceInfo | Stores additional per-server information about the regions added/removed
 during the run of the balancing algorithm. | 
| StochasticLoadBalancer | This is a best effort load balancer. | 
| StochasticLoadBalancer.CostFromRegionLoadAsRateFunction | Class to be used for the subset of RegionLoad costs that should be treated as rates. | 
| StochasticLoadBalancer.CostFromRegionLoadFunction | Base class the allows writing costs functions from rolling average of some
 number from RegionLoad. | 
| StochasticLoadBalancer.CostFunction | Base class of StochasticLoadBalancer's Cost Functions. | 
| StochasticLoadBalancer.LocalityBasedCostFunction | Compute a cost of a potential cluster configuration based upon where
  HStoreFiles are located. | 
| StochasticLoadBalancer.MemStoreSizeCostFunction | Compute the cost of total memstore size. | 
| StochasticLoadBalancer.MoveCostFunction | Given the starting state of the regions and a potential ending state
 compute cost based upon the number of regions that have moved. | 
| StochasticLoadBalancer.PrimaryRegionCountSkewCostFunction | Compute the cost of a potential cluster state from skew in number of
 primary regions on a cluster. | 
| StochasticLoadBalancer.RackLocalityCostFunction | |
| StochasticLoadBalancer.RandomCandidateGenerator | |
| StochasticLoadBalancer.ReadRequestCostFunction | Compute the cost of total number of read requests  The more unbalanced the higher the
 computed cost will be. | 
| StochasticLoadBalancer.RegionCountSkewCostFunction | Compute the cost of a potential cluster state from skew in number of
 regions on a cluster. | 
| StochasticLoadBalancer.RegionReplicaHostCostFunction | A cost function for region replicas. | 
| StochasticLoadBalancer.RegionReplicaRackCandidateGenerator | Generates candidates which moves the replicas out of the rack for
 co-hosted region replicas in the same rack | 
| StochasticLoadBalancer.RegionReplicaRackCostFunction | A cost function for region replicas for the rack distribution. | 
| StochasticLoadBalancer.ServerLocalityCostFunction | |
| StochasticLoadBalancer.StoreFileCostFunction | Compute the cost of total open storefiles size. | 
| StochasticLoadBalancer.TableSkewCostFunction | Compute the cost of a potential cluster configuration based upon how evenly
 distributed tables are. | 
| StochasticLoadBalancer.WriteRequestCostFunction | Compute the cost of total number of write requests. | 
| Enum | Description | 
|---|---|
| BaseLoadBalancer.Cluster.Action.Type | |
| BaseLoadBalancer.Cluster.LocalityType | 
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