org.apache.hadoop.hbase.client

Class MasterRegistry

java.lang.Object

org.apache.hadoop.hbase.client.MasterRegistry

@InterfaceAudience.Private
public class MasterRegistry
extends Object

Master based registry implementation. Makes RPCs to the configured master addresses from config "hbase.masters".

It supports hedged reads, set the fan out of the requests batch by MASTER_REGISTRY_HEDGED_REQS_FANOUT_KEY to a value greater than 1 will enable it(the default value is MASTER_REGISTRY_HEDGED_REQS_FANOUT_DEFAULT).

TODO: Handle changes to the configuration dynamically without having to restart the client.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MASTER_REGISTRY_HEDGED_REQS_FANOUT_DEFAULT Default value for the fan out of hedged requests.
static String	MASTER_REGISTRY_HEDGED_REQS_FANOUT_KEY Configuration key that controls the fan out of requests
protected MasterAddressRefresher	masterAddressRefresher

Method Summary

Modifier and Type	Method and Description
void	close() Closes this instance and releases any system resources associated with it
CompletableFuture<ServerName>	getActiveMaster() Get the address of active HMaster.
CompletableFuture<String>	getClusterId() Should only be called once.
static String	getMasterAddr(org.apache.hadoop.conf.Configuration conf) Builds the default master address end point if it is not specified in the configuration.
CompletableFuture<RegionLocations>	getMetaRegionLocations() Get the location of meta region(s).

Methods inherited from class java.lang.Object

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

Field Detail

MASTER_REGISTRY_HEDGED_REQS_FANOUT_KEY

public static final String MASTER_REGISTRY_HEDGED_REQS_FANOUT_KEY

Configuration key that controls the fan out of requests

See Also:

Constant Field Values

MASTER_REGISTRY_HEDGED_REQS_FANOUT_DEFAULT

public static final int MASTER_REGISTRY_HEDGED_REQS_FANOUT_DEFAULT

Default value for the fan out of hedged requests.

See Also:

Constant Field Values

masterAddressRefresher

protected final MasterAddressRefresher masterAddressRefresher

Method Detail

getMasterAddr

public static String getMasterAddr(org.apache.hadoop.conf.Configuration conf)
                            throws UnknownHostException

Builds the default master address end point if it is not specified in the configuration.

Will be called in HBaseTestingUtility.

Throws:

UnknownHostException

getMetaRegionLocations

public CompletableFuture<RegionLocations> getMetaRegionLocations()

Get the location of meta region(s).

getClusterId

public CompletableFuture<String> getClusterId()

Should only be called once.

The upper layer should store this value somewhere as it will not be change any more.

getActiveMaster

public CompletableFuture<ServerName> getActiveMaster()

Get the address of active HMaster.

close

public void close()

Closes this instance and releases any system resources associated with it