org.apache.hadoop.hbase.catalog
Class CatalogTracker

java.lang.Object
  org.apache.hadoop.hbase.catalog.CatalogTracker

public class CatalogTracker
extends java.lang.Object

Tracks the availability of the catalog tables -ROOT- and .META.. This class is "read-only" in that the locations of the catalog tables cannot be explicitly set. Instead, ZooKeeper is used to learn of the availability and location of -ROOT-. -ROOT- is used to learn of the location of .META. If not available in -ROOT-, ZooKeeper is used to monitor for a new location of .META..

Call start() to start up operation. Call stop()} to interrupt waits and close up shop.

Field Summary

static byte[]	META_REGION
static byte[]	ROOT_REGION

Constructor Summary

CatalogTracker(HConnection connection)
Constructs a catalog tracker.

CatalogTracker(ZooKeeperWatcher zk, HConnection connection, Abortable abortable)
Constructs the catalog tracker.

CatalogTracker(ZooKeeperWatcher zk, HConnection connection, Abortable abortable, int defaultTimeout)
Constructs the catalog tracker.

Method Summary

HConnection	getConnection()
HServerAddress	getMetaLocation()
HServerAddress	getRootLocation() Gets the current location for -ROOT- or null if location is not currently available.
void	start() Starts the catalog tracker.
void	stop() Stop working.
boolean	verifyMetaRegionLocation(long timeout) Verify .META. is deployed and accessible.
boolean	verifyRootRegionLocation(long timeout) Verify -ROOT- is deployed and accessible.
void	waitForMeta() Waits indefinitely for availability of .META..
HServerAddress	waitForMeta(long timeout) Gets the current location for .META. if available and waits for up to the specified timeout if not immediately available.
HRegionInterface	waitForMetaServerConnection(long timeout) Gets a connection to the server hosting meta, as reported by ZooKeeper, waiting up to the specified timeout for availability.
HRegionInterface	waitForMetaServerConnectionDefault() Gets a connection to the server hosting meta, as reported by ZooKeeper, waiting up to the specified timeout for availability.
void	waitForRoot() Waits indefinitely for availability of -ROOT-.
HRegionInterface	waitForRootServerConnection(long timeout) Gets a connection to the server hosting root, as reported by ZooKeeper, waiting up to the specified timeout for availability.
HRegionInterface	waitForRootServerConnectionDefault() Gets a connection to the server hosting root, as reported by ZooKeeper, waiting for the default timeout specified on instantiation.

Methods inherited from class java.lang.Object

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

Field Detail

ROOT_REGION

public static final byte[] ROOT_REGION

META_REGION

public static final byte[] META_REGION

Constructor Detail

CatalogTracker

public CatalogTracker(HConnection connection)
               throws java.io.IOException

Constructs a catalog tracker. Find current state of catalog tables and begin active tracking by executing start() post construction. Does not timeout.

Parameters:

connection - Server connection; if problem, this connections Abortable.abort(String, Throwable) will be called.

Throws:

java.io.IOException

CatalogTracker

public CatalogTracker(ZooKeeperWatcher zk,
                      HConnection connection,
                      Abortable abortable)
               throws java.io.IOException

Constructs the catalog tracker. Find current state of catalog tables and begin active tracking by executing start() post construction. Does not timeout.

Parameters:

zk -

connection - server connection

abortable - if fatal exception

Throws:

java.io.IOException

CatalogTracker

public CatalogTracker(ZooKeeperWatcher zk,
                      HConnection connection,
                      Abortable abortable,
                      int defaultTimeout)
               throws java.io.IOException

Constructs the catalog tracker. Find current state of catalog tables and begin active tracking by executing start() post construction.

Parameters:

zk -

connection - server connection

abortable - if fatal exception

defaultTimeout - Timeout to use. Pass zero for no timeout (Object.wait(long) when passed a 0 waits for ever).

Throws:

java.io.IOException

Method Detail

start

public void start()
           throws java.io.IOException,
                  java.lang.InterruptedException

Starts the catalog tracker. Determines current availability of catalog tables and ensures all further transitions of either region are tracked.

Throws:

java.io.IOException

java.lang.InterruptedException

stop

public void stop()

Stop working. Interrupts any ongoing waits.

getRootLocation

public HServerAddress getRootLocation()
                               throws java.lang.InterruptedException

Gets the current location for -ROOT- or null if location is not currently available.

Returns:

location of root, null if not available

Throws:

java.lang.InterruptedException

getMetaLocation

public HServerAddress getMetaLocation()

Returns:

Location of meta or null if not yet available.

waitForRoot

public void waitForRoot()
                 throws java.lang.InterruptedException

Waits indefinitely for availability of -ROOT-. Used during cluster startup.

Throws:

java.lang.InterruptedException - if interrupted while waiting

waitForRootServerConnection

public HRegionInterface waitForRootServerConnection(long timeout)
                                             throws java.lang.InterruptedException,
                                                    NotAllMetaRegionsOnlineException,
                                                    java.io.IOException

Gets a connection to the server hosting root, as reported by ZooKeeper, waiting up to the specified timeout for availability.

Returns:

connection to server hosting root

Throws:

java.lang.InterruptedException

NotAllMetaRegionsOnlineException - if timed out waiting

java.io.IOException

See Also:

for additional information

waitForRootServerConnectionDefault

public HRegionInterface waitForRootServerConnectionDefault()
                                                    throws NotAllMetaRegionsOnlineException,
                                                           java.io.IOException

Gets a connection to the server hosting root, as reported by ZooKeeper, waiting for the default timeout specified on instantiation.

Returns:

connection to server hosting root

Throws:

NotAllMetaRegionsOnlineException - if timed out waiting

java.io.IOException

See Also:

for additional information

waitForMeta

public void waitForMeta()
                 throws java.lang.InterruptedException

Waits indefinitely for availability of .META.. Used during cluster startup.

Throws:

java.lang.InterruptedException - if interrupted while waiting

waitForMeta

public HServerAddress waitForMeta(long timeout)
                           throws java.lang.InterruptedException,
                                  java.io.IOException,
                                  NotAllMetaRegionsOnlineException

Gets the current location for .META. if available and waits for up to the specified timeout if not immediately available. Throws an exception if timed out waiting. This method differs from waitForMeta() in that it will go ahead and verify the location gotten from ZooKeeper by trying to use returned connection.

Parameters:

timeout - maximum time to wait for meta availability, in milliseconds

Returns:

location of meta

Throws:

java.lang.InterruptedException - if interrupted while waiting

java.io.IOException - unexpected exception connecting to meta server

NotAllMetaRegionsOnlineException - if meta not available before timeout

waitForMetaServerConnection

public HRegionInterface waitForMetaServerConnection(long timeout)
                                             throws java.lang.InterruptedException,
                                                    NotAllMetaRegionsOnlineException,
                                                    java.io.IOException

Gets a connection to the server hosting meta, as reported by ZooKeeper, waiting up to the specified timeout for availability.

Returns:

connection to server hosting meta

Throws:

java.lang.InterruptedException

NotAllMetaRegionsOnlineException - if timed out waiting

java.io.IOException

See Also:

for additional information

waitForMetaServerConnectionDefault

public HRegionInterface waitForMetaServerConnectionDefault()
                                                    throws NotAllMetaRegionsOnlineException,
                                                           java.io.IOException

Gets a connection to the server hosting meta, as reported by ZooKeeper, waiting up to the specified timeout for availability.

Returns:

connection to server hosting meta

Throws:

NotAllMetaRegionsOnlineException - if timed out or interrupted

java.io.IOException

See Also:

for additional information

verifyRootRegionLocation

public boolean verifyRootRegionLocation(long timeout)
                                 throws java.lang.InterruptedException,
                                        java.io.IOException

Verify -ROOT- is deployed and accessible.

Parameters:

timeout - How long to wait on zk for root address (passed through to the internal call to waitForRootServerConnection(long).

Returns:

True if the -ROOT- location is healthy.

Throws:

java.io.IOException

java.lang.InterruptedException

verifyMetaRegionLocation

public boolean verifyMetaRegionLocation(long timeout)
                                 throws java.lang.InterruptedException,
                                        java.io.IOException

Verify .META. is deployed and accessible.

Parameters:

timeout - How long to wait on zk for .META. address (passed through to the internal call to waitForMetaServerConnection(long).

Returns:

True if the .META. location is healthy.

Throws:

java.io.IOException - Some unexpected IOE.

java.lang.InterruptedException

getConnection

public HConnection getConnection()