BaseLoadBalancer.Cluster (Apache HBase 1.4.11 API)

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

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

Constructor Summary

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

Method Summary

Methods
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

BaseLoadBalancer.Cluster

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

BaseLoadBalancer.Cluster

protected BaseLoadBalancer.Cluster(Collection<HRegionInfo> unassignedRegions,
                        Map<ServerName,List<HRegionInfo>> clusterState,
                        Map<String,Deque<RegionLoad>> 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

Class BaseLoadBalancer.Cluster

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

rackManager

NullAction

Constructor Detail

BaseLoadBalancer.Cluster

BaseLoadBalancer.Cluster

Method Detail

serverHasTooFewRegions

getOrComputeRackLocalities

getOrComputeRegionsToMostLocalEntities

getOrComputeLocality

getOrComputeWeightedLocality

getRegionSizeMB

getRackForRegion

doAction

setNumRegions

setNumMovedRegions

toString