org.apache.hadoop.hbase.master.balancer

Class BaseLoadBalancer.Cluster

java.lang.Object

org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster

Enclosing class:

BaseLoadBalancer

protected static class BaseLoadBalancer.Cluster
extends Object

An efficient array based implementation similar to ClusterState for keeping the status of the cluster in terms of region assignment and distribution. LoadBalancers, such as StochasticLoadBalancer uses this Cluster object because of hundreds of thousands of hashmap manipulations are very costly, which is why this class uses mostly indexes and arrays. Cluster tracks a list of unassigned regions, region assignments, and the server topology in terms of server names, hostnames and racks.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BaseLoadBalancer.Cluster.Action An action to move or swap a region
static class	BaseLoadBalancer.Cluster.AssignRegionAction
static class	BaseLoadBalancer.Cluster.MoveRegionAction
static class	BaseLoadBalancer.Cluster.SwapRegionsAction

Field Summary

Fields

Modifier and Type	Field and Description
static BaseLoadBalancer.Cluster.Action	NullAction
protected RackManager	rackManager

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Cluster(Collection<RegionInfo> unassignedRegions, Map<ServerName,List<RegionInfo>> clusterState, Map<String,Deque<org.apache.hadoop.hbase.master.balancer.BalancerRegionLoad>> loads, org.apache.hadoop.hbase.master.balancer.RegionLocationFinder regionFinder, RackManager rackManager)
protected	Cluster(Map<ServerName,List<RegionInfo>> clusterState, Map<String,Deque<org.apache.hadoop.hbase.master.balancer.BalancerRegionLoad>> loads, org.apache.hadoop.hbase.master.balancer.RegionLocationFinder regionFinder, RackManager rackManager)

Method Summary

Modifier and Type	Method and Description
void	doAction(BaseLoadBalancer.Cluster.Action action)
float	getOrComputeLocality(int region, int entity, org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type) Looks up locality from cache of localities.
float[][]	getOrComputeRackLocalities() Retrieves and lazily initializes a field storing the locality of every region/server combination
int[]	getOrComputeRegionsToMostLocalEntities(org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type) Lazily initializes and retrieves a mapping of region -> server for which region has the highest the locality
double	getOrComputeWeightedLocality(int region, int server, org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type) Returns locality weighted by region size in MB.
int	getRackForRegion(int region) Maps region index to rack index
int	getRegionSizeMB(int region) Returns the size in MB from the most recent RegionLoad for region
boolean	serverHasTooFewRegions(int server) Returns true iff a given server has less regions than the balanced amount
protected void	setNumMovedRegions(int numMovedRegions)
protected void	setNumRegions(int numRegions)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

rackManager

protected final RackManager rackManager

NullAction

public static final BaseLoadBalancer.Cluster.Action NullAction

Constructor Detail

Cluster

protected Cluster(Map<ServerName,List<RegionInfo>> clusterState,
                  Map<String,Deque<org.apache.hadoop.hbase.master.balancer.BalancerRegionLoad>> loads,
                  org.apache.hadoop.hbase.master.balancer.RegionLocationFinder regionFinder,
                  RackManager rackManager)

Cluster

protected Cluster(Collection<RegionInfo> unassignedRegions,
                  Map<ServerName,List<RegionInfo>> clusterState,
                  Map<String,Deque<org.apache.hadoop.hbase.master.balancer.BalancerRegionLoad>> loads,
                  org.apache.hadoop.hbase.master.balancer.RegionLocationFinder regionFinder,
                  RackManager rackManager)

Method Detail

serverHasTooFewRegions

public boolean serverHasTooFewRegions(int server)

Returns true iff a given server has less regions than the balanced amount

getOrComputeRackLocalities

public float[][] getOrComputeRackLocalities()

Retrieves and lazily initializes a field storing the locality of every region/server combination

getOrComputeRegionsToMostLocalEntities

public int[] getOrComputeRegionsToMostLocalEntities(org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type)

Lazily initializes and retrieves a mapping of region -> server for which region has the highest the locality

getOrComputeLocality

public float getOrComputeLocality(int region,
                                  int entity,
                                  org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type)

Looks up locality from cache of localities. Will create cache if it does not already exist.

getOrComputeWeightedLocality

public double getOrComputeWeightedLocality(int region,
                                           int server,
                                           org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType type)

Returns locality weighted by region size in MB. Will create locality cache if it does not already exist.

getRegionSizeMB

public int getRegionSizeMB(int region)

Returns the size in MB from the most recent RegionLoad for region

getRackForRegion

public int getRackForRegion(int region)

Maps region index to rack index

doAction

public void doAction(BaseLoadBalancer.Cluster.Action action)

setNumRegions

protected void setNumRegions(int numRegions)

setNumMovedRegions

protected void setNumMovedRegions(int numMovedRegions)

toString

public String toString()

Overrides:

toString in class Object