Package org.apache.zookeeper.server.quorum

Class ObserverMaster

java.lang.Object

org.apache.zookeeper.server.quorum.LearnerMaster

org.apache.zookeeper.server.quorum.ObserverMaster

All Implemented Interfaces:

Runnable

public class ObserverMaster
extends LearnerMaster
implements Runnable

Used by Followers to host Observers. This reduces the network load on the Leader process by pushing the responsibility for keeping Observers in sync off the leading peer. It is expected that Observers will continue to perform the initial vetting of clients and requests. Observers send the request to the follower where it is received by an ObserverMaster. The ObserverMaster forwards a copy of the request to the ensemble Leader and inserts it into its own request processor pipeline where it can be matched with the response comes back. All commits received from the Leader will be forwarded along to every Learner connected to the ObserverMaster. New Learners connecting to a Follower will receive a LearnerHandler object and be party to its syncing logic to be brought up to date. The logic is quite a bit simpler than the corresponding logic in Leader because it only hosts observers.

Method Summary

Modifier and Type	Method	Description
void	addLearnerHandler(LearnerHandler learnerHandler)
Iterable<Map<String,Object>>	getActiveObservers()
long	getAndDecrementFollowerCounter()
int	getCurrentTick()
long	getEpochToPropose(long sid, long lastAcceptedEpoch)
long	getLastProposed()
String	getPeerInfo(long sid)
QuorumAuthServer	getQuorumAuthServer()
byte[]	getQuorumVerifierBytes()
long	getQuorumVerifierVersion()
int	getTickOfInitialAckDeadline()
int	getTickOfNextAckDeadline()
ZKDatabase	getZKDatabase()
void	processAck(long sid, long zxid, SocketAddress localSocketAddress)
void	registerLearnerHandlerBean(LearnerHandler learnerHandler, Socket socket)
void	removeLearnerHandler(LearnerHandler learnerHandler)
void	resetObserverConnectionStats()
void	revalidateSession(QuorumPacket qp, LearnerHandler learnerHandler)
void	run()
void	start()
long	startForwarding(LearnerHandler learnerHandler, long lastSeenZxid)
void	stop()
void	submitLearnerRequest(Request si)
int	syncTimeout()
void	touch(long sess, int to)
void	unregisterLearnerHandlerBean(LearnerHandler learnerHandler)
void	waitForEpochAck(long sid, StateSummary ss)
void	waitForNewLeaderAck(long sid, long zxid)
void	waitForStartup()

Methods inherited from class org.apache.zookeeper.server.quorum.LearnerMaster

getLearnerDiffSyncThrottler, getLearnerSnapSyncThrottler, getMaxConcurrentDiffSyncs, getMaxConcurrentSnapSyncs, setMaxConcurrentDiffSyncs, setMaxConcurrentSnapSyncs

Methods inherited from class java.lang.Object

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

Method Detail

addLearnerHandler

public void addLearnerHandler(LearnerHandler learnerHandler)

removeLearnerHandler

public void removeLearnerHandler(LearnerHandler learnerHandler)

syncTimeout

public int syncTimeout()

getTickOfNextAckDeadline

public int getTickOfNextAckDeadline()

getTickOfInitialAckDeadline

public int getTickOfInitialAckDeadline()

getAndDecrementFollowerCounter

public long getAndDecrementFollowerCounter()

waitForEpochAck

public void waitForEpochAck(long sid,
                            StateSummary ss)
                     throws IOException,
                            InterruptedException

Throws:

IOException

InterruptedException

waitForStartup

public void waitForStartup()
                    throws InterruptedException

Throws:

InterruptedException

getLastProposed

public long getLastProposed()

getEpochToPropose

public long getEpochToPropose(long sid,
                              long lastAcceptedEpoch)
                       throws InterruptedException,
                              IOException

Throws:

InterruptedException

IOException

getZKDatabase

public ZKDatabase getZKDatabase()

waitForNewLeaderAck

public void waitForNewLeaderAck(long sid,
                                long zxid)
                         throws InterruptedException

Throws:

InterruptedException

getCurrentTick

public int getCurrentTick()

processAck

public void processAck(long sid,
                       long zxid,
                       SocketAddress localSocketAddress)

touch

public void touch(long sess,
                  int to)

revalidateSession

public void revalidateSession(QuorumPacket qp,
                              LearnerHandler learnerHandler)
                       throws IOException

Throws:

IOException

submitLearnerRequest

public void submitLearnerRequest(Request si)

startForwarding

public long startForwarding(LearnerHandler learnerHandler,
                            long lastSeenZxid)

getQuorumVerifierVersion

public long getQuorumVerifierVersion()

getPeerInfo

public String getPeerInfo(long sid)

getQuorumVerifierBytes

public byte[] getQuorumVerifierBytes()

getQuorumAuthServer

public QuorumAuthServer getQuorumAuthServer()

start

public void start()
           throws IOException

Throws:

IOException

run

public void run()

Specified by:

run in interface Runnable

stop

public void stop()

getActiveObservers

public Iterable<Map<String,Object>> getActiveObservers()

resetObserverConnectionStats

public void resetObserverConnectionStats()

registerLearnerHandlerBean

public void registerLearnerHandlerBean(LearnerHandler learnerHandler,
                                       Socket socket)

unregisterLearnerHandlerBean

public void unregisterLearnerHandlerBean(LearnerHandler learnerHandler)