com.continuent.tungsten.replicator.storage
Class InMemoryTransactionalQueue

java.lang.Object
  com.continuent.tungsten.replicator.storage.InMemoryTransactionalQueue

All Implemented Interfaces:

ReplicatorPlugin, Store

public class InMemoryTransactionalQueue
extends java.lang.Object
implements Store

Implements an in-memory queue store that applies events from multiple task threads (i.e., channels) into a single centralized queue. The queue has transactional semantics in the sense that it buffers events from each task thread and them applies them in a single operation upon commit. This is helpful for detecting out-of-order apply due to errors in the synchronization of parallel tasks.

To further simulate DBMS behavior this queue supports commit actions, which may perform arbitrary actions such as delaying or throwing exceptions.

Version:

1.0

Author:

Robert Hodges

Constructor Summary

InMemoryTransactionalQueue()

Method Summary

void	commit(int taskId) Commits all pending events for a particular task.
void	configure(PluginContext context) Complete plug-in configuration.
ReplDBMSEvent	get() Removes and returns next event from the queue, blocking if empty.
CommitAction	getCommitAction() An action to invoke prior to commit.
int	getCommitTimeout() Maximum commit timeout (fails after this) in seconds.
ReplDBMSHeader	getLastHeader(int taskId) Returns the last header processed.
int	getMaxSize() Maximum number of events permitted in serial queue.
long	getMaxStoredSeqno() Returns the maximum persistently stored sequence number.
long	getMinStoredSeqno() Returns the minimum persistently stored sequence number.
java.lang.String	getName() Gets the storage name.
int	getPartitions() Number of partitions supported by the queue.
ReplDBMSEvent	peek() Returns but does not remove next event from the queue if it exists or returns null if queue is empty.
void	prepare(PluginContext context) Allocate an in-memory queue.
void	put(int taskId, ReplDBMSEvent event) Puts an event in the local task queue, where it is buffered in order until commit or rollback.
void	release(PluginContext context) Release queue.
void	rollback(int taskId) Rolls back pending events for a particular task.
void	setCommitAction(CommitAction commitAction)
void	setCommitTimeout(int commitTimeout)
void	setLastHeader(int taskId, ReplDBMSHeader header) Sets the last header processed.
void	setMaxSize(int size)
void	setName(java.lang.String name) Sets the storage name.
void	setPartitions(int partitions)
int	size() Returns the current serial queue size.
TungstenProperties	status() Returns status information as a set of named properties.

Methods inherited from class java.lang.Object

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

Constructor Detail

InMemoryTransactionalQueue

public InMemoryTransactionalQueue()

Method Detail

getName

public java.lang.String getName()

Gets the storage name.

Specified by:

getName in interface Store

See Also:

Store.getName()

setName

public void setName(java.lang.String name)

Sets the storage name.

Specified by:

setName in interface Store

See Also:

Store.setName(java.lang.String)

getMaxSize

public int getMaxSize()

Maximum number of events permitted in serial queue.

setMaxSize

public void setMaxSize(int size)

getPartitions

public int getPartitions()

Number of partitions supported by the queue.

setPartitions

public void setPartitions(int partitions)

getCommitTimeout

public int getCommitTimeout()

Maximum commit timeout (fails after this) in seconds.

setCommitTimeout

public void setCommitTimeout(int commitTimeout)

getCommitAction

public CommitAction getCommitAction()

An action to invoke prior to commit.

setCommitAction

public void setCommitAction(CommitAction commitAction)

setLastHeader

public void setLastHeader(int taskId,
                          ReplDBMSHeader header)

Sets the last header processed. This is required for restart.

getLastHeader

public ReplDBMSHeader getLastHeader(int taskId)

Returns the last header processed.

getMaxStoredSeqno

public long getMaxStoredSeqno()

Returns the maximum persistently stored sequence number.

Specified by:

getMaxStoredSeqno in interface Store

See Also:

Store.getMaxStoredSeqno()

getMinStoredSeqno

public long getMinStoredSeqno()

Returns the minimum persistently stored sequence number.

Specified by:

getMinStoredSeqno in interface Store

See Also:

Store.getMinStoredSeqno()

put

public void put(int taskId,
                ReplDBMSEvent event)
         throws java.lang.InterruptedException,
                ReplicatorException

Puts an event in the local task queue, where it is buffered in order until commit or rollback.

Throws:

java.lang.InterruptedException

ReplicatorException

commit

public void commit(int taskId)
            throws java.lang.InterruptedException,
                   ReplicatorException

Commits all pending events for a particular task.

Throws:

java.lang.InterruptedException

ReplicatorException

rollback

public void rollback(int taskId)

Rolls back pending events for a particular task.

Throws:

java.lang.InterruptedException

get

public ReplDBMSEvent get()
                  throws java.lang.InterruptedException

Removes and returns next event from the queue, blocking if empty.

Throws:

java.lang.InterruptedException

peek

public ReplDBMSEvent peek()

Returns but does not remove next event from the queue if it exists or returns null if queue is empty.

size

public int size()

Returns the current serial queue size.

configure

public void configure(PluginContext context)
               throws ReplicatorException

Complete plug-in configuration. This is called after setters are invoked at the time that the replicator goes through configuration.

Specified by:

configure in interface ReplicatorPlugin

Throws:

ReplicatorException - Thrown if configuration is incomplete or fails

See Also:

ReplicatorPlugin.configure(com.continuent.tungsten.replicator.plugin.PluginContext)

prepare

public void prepare(PluginContext context)
             throws ReplicatorException

Allocate an in-memory queue. Prepare plug-in for use. This method is assumed to allocate all required resources. It is called before the plug-in performs any operations.

Specified by:

prepare in interface ReplicatorPlugin

Throws:

ReplicatorException - Thrown if resource allocation fails

See Also:

ReplicatorPlugin.prepare(com.continuent.tungsten.replicator.plugin.PluginContext)

release

public void release(PluginContext context)
             throws ReplicatorException

Release queue. Release all resources used by plug-in. This is called before the plug-in is deallocated.

Specified by:

release in interface ReplicatorPlugin

Throws:

ReplicatorException - Thrown if resource deallocation fails

See Also:

ReplicatorPlugin.release(com.continuent.tungsten.replicator.plugin.PluginContext)

status

public TungstenProperties status()

Returns status information as a set of named properties.

Specified by:

status in interface Store

See Also:

Store.status()