org.apache.derby.impl.store.replication.master

Class MasterController

java.lang.Object

org.apache.derby.impl.store.replication.master.MasterController

All Implemented Interfaces:

ModuleControl, ModuleSupportable, MasterFactory

public class MasterController
extends java.lang.Object
implements MasterFactory, ModuleControl, ModuleSupportable

This is an implementation of the replication master controller service. The service is booted when this instance of Derby will have the replication master role for this database.

Note: The current version of the class is far from complete. Code to control the replication master behavior will be added as more parts of the replication functionality is added to Derby.

See Also:

MasterFactory

Field Summary

Fields inherited from interface org.apache.derby.iapi.store.replication.master.MasterFactory

ASYNCHRONOUS_MODE, MODULE, REPLICATION_MODE

Constructor Summary

Constructors

Constructor and Description
MasterController() Empty constructor required by Monitor.bootServiceModule

Method Summary

Modifier and Type	Method and Description
void	appendLog(long greatestInstant, byte[] log, int logOffset, int logLength) Append a chunk of log records to the log buffer.
void	boot(boolean create, java.util.Properties properties) Used by Monitor.bootServiceModule to start the service.
boolean	canSupport(java.util.Properties startParams) Used by Monitor.bootServiceModule to check if this class is usable for replication.
void	flushedTo(long instant) Used by the LogFactory to notify the replication master controller that the log records up to this instant have been flushed to disk.
void	startFailover() Will perform all work needed to failover
void	startMaster(RawStoreFactory rawStore, DataFactory dataFac, LogFactory logFac, java.lang.String slavehost, int slaveport, java.lang.String dbname) Will perform all the work that is needed to set up replication.
void	stop() Will stop the replication master service.
void	stopMaster() Will perform all work that is needed to shut down replication.
void	workToDo() Used to notify the log shipper that a log buffer element is full.

Methods inherited from class java.lang.Object

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

Constructor Detail

MasterController

public MasterController()

Empty constructor required by Monitor.bootServiceModule

Method Detail

boot

public void boot(boolean create,
                 java.util.Properties properties)
          throws StandardException

Used by Monitor.bootServiceModule to start the service. Currently only used to set up the replication mode.

Specified by:

boot in interface ModuleControl

Parameters:

create - Currently ignored

properties - Properties used to start the service in the correct mode. Currently initializes only the replicationMode property.

Throws:

StandardException - Standard Derby exception policy, thrown on error.

See Also:

Monitor, ModuleFactory

canSupport

public boolean canSupport(java.util.Properties startParams)

Used by Monitor.bootServiceModule to check if this class is usable for replication. To be usable, we require that asynchronous replication is specified in startParams by checking that a property with key MasterFactory.REPLICATION_MODE has the value MasterFactory.ASYNCHRONOUS_MODE.

Specified by:

canSupport in interface ModuleSupportable

Parameters:

startParams - The properties used to boot replication

Returns:

true if asynchronous replication is requested, meaning that this MasterController is a suitable implementation for the MasterFactory service. False otherwise

See Also:

ModuleSupportable.canSupport(java.util.Properties)

stop

public void stop()

Will stop the replication master service.

Specified by:

stop in interface ModuleControl

See Also:

Monitor, ModuleFactory

startMaster

public void startMaster(RawStoreFactory rawStore,
                        DataFactory dataFac,
                        LogFactory logFac,
                        java.lang.String slavehost,
                        int slaveport,
                        java.lang.String dbname)
                 throws StandardException

Will perform all the work that is needed to set up replication.

Specified by:

startMaster in interface MasterFactory

Parameters:

rawStore - The RawStoreFactory for the database

dataFac - The DataFactory for this database

logFac - The LogFactory ensuring recoverability for this database

slavehost - The hostname of the slave

slaveport - The port the slave is listening on

dbname - The master database that is being replicated.

Throws:

StandardException - Standard Derby exception policy, 1) thrown on replication startup error 2) thrown if the master has already been booted. 3) thrown if the specified replication mode is not supported.

stopMaster

public void stopMaster()
                throws StandardException

Will perform all work that is needed to shut down replication.

Specified by:

stopMaster in interface MasterFactory

Throws:

StandardException - If the replication master has been stopped already.

startFailover

public void startFailover()
                   throws StandardException

Description copied from interface: MasterFactory

Will perform all work needed to failover

Specified by:

startFailover in interface MasterFactory

Throws:

StandardException - 1) If the failover succeeds, an exception is thrown to indicate that the master database was shutdown after a successful failover 2) If a failure occurs during network communication with slave.

See Also:

MasterFactory.startFailover()

appendLog

public void appendLog(long greatestInstant,
                      byte[] log,
                      int logOffset,
                      int logLength)

Append a chunk of log records to the log buffer. The method is not threadsafe; only one thread should access this method at a time.

Specified by:

appendLog in interface MasterFactory

Parameters:

greatestInstant - the instant of the log record that was added last to this chunk of log

log - the chunk of log records

logOffset - offset in log to start copy from

logLength - number of bytes to copy, starting from logOffset

flushedTo

public void flushedTo(long instant)

Used by the LogFactory to notify the replication master controller that the log records up to this instant have been flushed to disk. The master controller takes action according to the current replication strategy when this method is called. When the asynchronous replication strategy is used, the method does not force log shipping to the slave; the log records may be shipped now or later at the MasterController's discretion. However, if another strategy like 2-safe replication is implemented in the future, a call to this method may force log shipment before returning control to the caller. Currently, only asynchronous replication is supported. Not implemented yet

Specified by:

flushedTo in interface MasterFactory

Parameters:

instant - The highest log instant that has been flushed to disk

See Also:

MasterFactory.flushedTo(long), LogFactory.flush(org.apache.derby.iapi.store.raw.log.LogInstant)

workToDo

public void workToDo()

Used to notify the log shipper that a log buffer element is full.

Specified by:

workToDo in interface MasterFactory