Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.iapi.store.replication.master.MasterFactory

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

The replication master service is responsible for managing all replication related functionality on the master side of replication. This includes connecting to the slave, setting up a log buffer to temporarily store log records from the LogFactory, and to ship these log records to the slave.

The master controller currently only supports asynchronous replication. This means that there are no guarantees that transactions that have committed here (the master side) are also reflected on the slave side. However, the slave version of the database IS guaranteed to be transaction consistent. This implies that:

A transaction t that is committed on the master will either be fully reflected or not be reflected at all on the slave when the slave database is turned into a non-replicated database (that is, at failover time)
Slave execution of operations is in the same serial order as on the master because replication is based on redoing log records to the slave. By definition, log records are in serial order. This implies that if transaction t1 commits before t2 on the master, and t2 has been committed on the slave, t1 is also guaranteed to have committed on the slave.

Field Summary

Modifier and Type	Field and Description
public static final String	ASYNCHRONOUS_MODE Property value used to indicate that the service should be booted in asynchronous replication mode.
public static final String	MODULE The name of the Master Factory, used to boot the service.
public static final String	REPLICATION_MODE Property key to specify replication mode

Method Summary

Modifier and Type	Method and Description
public void	appendLog(long the instant of the log record that was added last to this chunk of log greatestInstant, byte[] the chunk of log records log, int offset in log to start copy from logOffset, int number of bytes to copy, starting from logOffset logLength) Append a chunk of log records to the log buffer.
public void	flushedTo(long The highest log instant that has been flushed to disk instant) Used by the LogFactory to notify the replication master controller that the log records up to this instant have been flushed to disk.
public void	startFailover() Will perform all work needed to failover
public void	startMaster(RawStoreFactory The RawStoreFactory for the database rawStore, DataFactory The DataFactory for this database dataFac, LogFactory The LogFactory ensuring recoverability for this database logFac, String The hostname for the slave slavehost, int The port the slave is listening on slaveport, String The master database that is being replicated. dbname) Will perform all the work that is needed to set up replication
public void	stopMaster() Will perform all work that is needed to shut down replication.
public void	workToDo() Used to notify the log shipper that a log buffer element is full.

Field Detail

ASYNCHRONOUS_MODE	back to summary
public static final String ASYNCHRONOUS_MODE Property value used to indicate that the service should be booted in asynchronous replication mode.

MODULE	back to summary
public static final String MODULE The name of the Master Factory, used to boot the service.

REPLICATION_MODE	back to summary
public static final String REPLICATION_MODE Property key to specify replication mode

Method Detail

appendLog	back to summary
public void appendLog(long greatestInstant, byte[] log, int logOffset, int logLength) Append a chunk of log records to the log buffer. Parameters greatestInstant:long the instant of the log record that was added last to this chunk of log log:byte[] the chunk of log records logOffset:int offset in log to start copy from logLength:int number of bytes to copy, starting from logOffset

appendLog

back to summary

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

Append a chunk of log records to the log buffer.

Parameters

greatestInstant:long: the instant of the log record that was added last to this chunk of log
log:byte[]: the chunk of log records
logOffset:int: offset in log to start copy from
logLength:int: number of bytes to copy, starting from logOffset

flushedTo back to summary

flushedTo	back to summary
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 MasterFactory'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. Parameters instant:long The highest log instant that has been flushed to disk See Also `LogFactory#flush`

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 MasterFactory'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.

Parameters

instant:long: The highest log instant that has been flushed to disk

See Also

LogFactory#flush

startFailover	back to summary
public void startFailover() throws StandardException Will perform all work needed to failover Exceptions 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.

startFailover

back to summary

public void startFailover() throws StandardException

Will perform all work needed to failover

Exceptions

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.

startMaster	back to summary
public void startMaster(RawStoreFactory rawStore, DataFactory dataFac, LogFactory logFac, String slavehost, int slaveport, String dbname) throws StandardException Will perform all the work that is needed to set up replication Parameters rawStore:RawStoreFactory The RawStoreFactory for the database dataFac:DataFactory The DataFactory for this database logFac:LogFactory The LogFactory ensuring recoverability for this database slavehost:String The hostname for the slave slaveport:int The port the slave is listening on dbname:String The master database that is being replicated. Exceptions StandardException: Standard Derby exception policy, thrown on replication startup error.

stopMaster	back to summary
public void stopMaster() throws StandardException Will perform all work that is needed to shut down replication. Exceptions StandardException: If the replication master has been stopped already.

stopMaster

back to summary

public void stopMaster() throws StandardException

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

Exceptions

StandardException:: If the replication master has been stopped already.

workToDo	back to summary
public void workToDo() Used to notify the log shipper that a log buffer element is full.

public Interface MasterFactory

Field Summary

Method Summary

Field Detail

Method Detail