org.apache.hadoop.hbase.zookeeper

Class MetaTableLocator

java.lang.Object

org.apache.hadoop.hbase.zookeeper.MetaTableLocator

@InterfaceAudience.Private
public final class MetaTableLocator
extends Object

Utility class to perform operation (get/wait for/verify/set/delete) on znode in ZooKeeper which keeps hbase:meta region server location.

Stateless class with a bunch of static methods. Doesn't manage resources passed in (e.g. Connection, ZKWatcher etc).

Meta region location is set by RegionServerServices. This class doesn't use ZK watchers, rather accesses ZK directly.

TODO: rewrite using RPC calls to master to find out about hbase:meta.

Field Summary

Fields

Modifier and Type	Field and Description
private static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Modifier	Constructor and Description
private	MetaTableLocator()

Method Summary

Modifier and Type	Method and Description
private static ServerName	blockUntilAvailable(ZKWatcher zkw, int replicaId, long timeout) Wait until the meta region is available and is not in transition.
static void	deleteMetaLocation(ZKWatcher zookeeper) Deletes the location of hbase:meta in ZooKeeper.
static void	deleteMetaLocation(ZKWatcher zookeeper, int replicaId)
static ServerName	getMetaRegionLocation(ZKWatcher zkw) Gets the meta region location, if available.
static ServerName	getMetaRegionLocation(ZKWatcher zkw, int replicaId) Gets the meta region location, if available.
static RegionState	getMetaRegionState(ZKWatcher zkw) Load the meta region state from the meta server ZNode.
static RegionState	getMetaRegionState(ZKWatcher zkw, int replicaId) Load the meta region state from the meta region server ZNode.
static void	setMetaLocation(ZKWatcher zookeeper, ServerName serverName, int replicaId, RegionState.State state) Sets the location of hbase:meta in ZooKeeper to the specified server address.
static void	setMetaLocation(ZKWatcher zookeeper, ServerName serverName, RegionState.State state) Sets the location of hbase:meta in ZooKeeper to the specified server address.
private static ServerName	waitMetaRegionLocation(ZKWatcher zkw, int replicaId, long timeout) Gets the meta region location, if available, and waits for up to the specified timeout if not immediately available.
static ServerName	waitMetaRegionLocation(ZKWatcher zkw, long timeout) Gets the meta region location, if available, and waits for up to the specified timeout if not immediately available.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.slf4j.Logger LOG

Constructor Detail

MetaTableLocator

private MetaTableLocator()

Method Detail

getMetaRegionLocation

public static ServerName getMetaRegionLocation(ZKWatcher zkw)

Gets the meta region location, if available. Does not block.

Parameters:

zkw - zookeeper connection to use

Returns:

server name or null if we failed to get the data.

getMetaRegionLocation

public static ServerName getMetaRegionLocation(ZKWatcher zkw,
                                               int replicaId)

Gets the meta region location, if available. Does not block.

Parameters:

zkw - reference to the ZKWatcher which also contains configuration and operation

replicaId - the ID of the replica

Returns:

server name

waitMetaRegionLocation

public static ServerName waitMetaRegionLocation(ZKWatcher zkw,
                                                long timeout)
                                         throws InterruptedException,
                                                NotAllMetaRegionsOnlineException

Gets the meta region location, if available, and waits for up to the specified timeout if not immediately available. Given the zookeeper notification could be delayed, we will try to get the latest data.

Parameters:

zkw - reference to the ZKWatcher which also contains configuration and operation

timeout - maximum time to wait, in millis

Returns:

server name for server hosting meta region formatted as per ServerName, or null if none available

Throws:

InterruptedException - if interrupted while waiting

NotAllMetaRegionsOnlineException - if a meta or root region is not online

waitMetaRegionLocation

private static ServerName waitMetaRegionLocation(ZKWatcher zkw,
                                                 int replicaId,
                                                 long timeout)
                                          throws InterruptedException,
                                                 NotAllMetaRegionsOnlineException

Gets the meta region location, if available, and waits for up to the specified timeout if not immediately available. Given the zookeeper notification could be delayed, we will try to get the latest data.

Parameters:

zkw - reference to the ZKWatcher which also contains configuration and operation

replicaId - the ID of the replica

timeout - maximum time to wait, in millis

Returns:

server name for server hosting meta region formatted as per ServerName, or null if none available

Throws:

InterruptedException - if waiting for the socket operation fails

NotAllMetaRegionsOnlineException - if a meta or root region is not online

setMetaLocation

public static void setMetaLocation(ZKWatcher zookeeper,
                                   ServerName serverName,
                                   RegionState.State state)
                            throws org.apache.zookeeper.KeeperException

Sets the location of hbase:meta in ZooKeeper to the specified server address.

Parameters:

zookeeper - zookeeper reference

serverName - The server hosting hbase:meta

state - The region transition state

Throws:

org.apache.zookeeper.KeeperException - unexpected zookeeper exception

setMetaLocation

public static void setMetaLocation(ZKWatcher zookeeper,
                                   ServerName serverName,
                                   int replicaId,
                                   RegionState.State state)
                            throws org.apache.zookeeper.KeeperException

Sets the location of hbase:meta in ZooKeeper to the specified server address.

Parameters:

zookeeper - reference to the ZKWatcher which also contains configuration and operation

serverName - the name of the server

replicaId - the ID of the replica

state - the state of the region

Throws:

org.apache.zookeeper.KeeperException - if a ZooKeeper operation fails

getMetaRegionState

public static RegionState getMetaRegionState(ZKWatcher zkw)
                                      throws org.apache.zookeeper.KeeperException

Load the meta region state from the meta server ZNode.

Throws:

org.apache.zookeeper.KeeperException

getMetaRegionState

public static RegionState getMetaRegionState(ZKWatcher zkw,
                                             int replicaId)
                                      throws org.apache.zookeeper.KeeperException

Load the meta region state from the meta region server ZNode.

Parameters:

zkw - reference to the ZKWatcher which also contains configuration and operation

replicaId - the ID of the replica n * @throws KeeperException if a ZooKeeper operation fails

Throws:

org.apache.zookeeper.KeeperException

deleteMetaLocation

public static void deleteMetaLocation(ZKWatcher zookeeper)
                               throws org.apache.zookeeper.KeeperException

Deletes the location of hbase:meta in ZooKeeper.

Parameters:

zookeeper - zookeeper reference

Throws:

org.apache.zookeeper.KeeperException - unexpected zookeeper exception

deleteMetaLocation

public static void deleteMetaLocation(ZKWatcher zookeeper,
                                      int replicaId)
                               throws org.apache.zookeeper.KeeperException

Throws:

org.apache.zookeeper.KeeperException

blockUntilAvailable

private static ServerName blockUntilAvailable(ZKWatcher zkw,
                                              int replicaId,
                                              long timeout)
                                       throws InterruptedException

Wait until the meta region is available and is not in transition.

Parameters:

zkw - reference to the ZKWatcher which also contains configuration and constants

replicaId - the ID of the replica

timeout - maximum time to wait in millis

Returns:

ServerName or null if we timed out.

Throws:

InterruptedException - if waiting for the socket operation fails