org.apache.cassandra.streaming

Class StreamSession

java.lang.Object

org.apache.cassandra.streaming.StreamSession

All Implemented Interfaces:

IEndpointStateChangeSubscriber, IFailureDetectionEventListener

public class StreamSession
extends java.lang.Object
implements IEndpointStateChangeSubscriber, IFailureDetectionEventListener

Handles the streaming a one or more section of one of more sstables to and from a specific remote node. Both this node and the remote one will create a similar symmetrical StreamSession. A streaming session has the following life-cycle: 1. Connections Initialization (a) A node (the initiator in the following) create a new StreamSession, initialize it (init()) and then start it (start()). Start will create a ConnectionHandler that will create two connections to the remote node (the follower in the following) with whom to stream and send a StreamInit message. The first connection will be the incoming connection for the initiator, and the second connection will be the outgoing. (b) Upon reception of that StreamInit message, the follower creates its own StreamSession, initialize it if it still does not exist, and attach connecting socket to its ConnectionHandler according to StreamInit message's isForOutgoing flag. (d) When the both incoming and outgoing connections are established, StreamSession calls StreamSession#onInitializationComplete method to start the streaming prepare phase (StreamResultFuture.startStreaming()). 2. Streaming preparation phase (a) This phase is started when the initiator onInitializationComplete() method is called. This method sends a PrepareMessage that includes what files/sections this node will stream to the follower (stored in a StreamTranferTask, each column family has it's own transfer task) and what the follower needs to stream back (StreamReceiveTask, same as above). If the initiator has nothing to receive from the follower, it goes directly to its Streaming phase. Otherwise, it waits for the follower PrepareMessage. (b) Upon reception of the PrepareMessage, the follower records which files/sections it will receive and send back its own PrepareMessage with a summary of the files/sections that will be sent to the initiator (prepare()). After having sent that message, the follower goes to its Streamning phase. (c) When the initiator receives the follower PrepareMessage, it records which files/sections it will receive and then goes to his own Streaming phase. 3. Streaming phase (a) The streaming phase is started by each node (the sender in the follower, but note that each side of the StreamSession may be sender for some of the files) involved by calling startStreamingFiles(). This will sequentially send a FileMessage for each file of each SteamTransferTask. Each FileMessage consists of a FileMessageHeader that indicates which file is coming and then start streaming the content for that file (StreamWriter in FileMessage.serialize()). When a file is fully sent, the fileSent() method is called for that file. If all the files for a StreamTransferTask are sent (StreamTransferTask.complete()), the task is marked complete (taskCompleted()). (b) On the receiving side, a SSTable will be written for the incoming file (StreamReader in FileMessage.deserialize()) and once the FileMessage is fully received, the file will be marked as complete (received()). When all files for the StreamReceiveTask have been received, the sstables are added to the CFS (and 2ndary index are built, StreamReceiveTask.complete()) and the task is marked complete (taskCompleted()) (b) If during the streaming of a particular file an I/O error occurs on the receiving end of a stream (FileMessage.deserialize), the node will retry the file (up to DatabaseDescriptor.getMaxStreamingRetries()) by sending a RetryMessage to the sender. On receiving a RetryMessage, the sender simply issue a new FileMessage for that file. (c) When all transfer and receive tasks for a session are complete, the move to the Completion phase (maybeCompleted()). 4. Completion phase (a) When a node has finished all transfer and receive task, it enter the completion phase (maybeCompleted()). If it had already received a CompleteMessage from the other side (it is in the WAIT_COMPLETE state), that session is done is is closed (closeSession()). Otherwise, the node switch to the WAIT_COMPLETE state and send a CompleteMessage to the other side.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StreamSession.SSTableStreamingSections
static class	StreamSession.State

Field Summary

Fields

Modifier and Type	Field and Description
ConnectionHandler	handler
java.net.InetAddress	peer

Constructor Summary

Constructors

Constructor and Description
StreamSession(java.net.InetAddress peer) Create new streaming session with the peer.

Method Summary

Methods

Modifier and Type	Method and Description
void	addStreamRequest(java.lang.String keyspace, java.util.Collection<Range<Token>> ranges, java.util.Collection<java.lang.String> columnFamilies) Request data fetch task to this session.
void	addTransferFiles(java.util.Collection<Range<Token>> ranges, java.util.Collection<SSTableReader> sstables) Set up transfer of the specific SSTables.
void	addTransferFiles(java.util.Collection<StreamSession.SSTableStreamingSections> sstableDetails)
void	addTransferRanges(java.lang.String keyspace, java.util.Collection<Range<Token>> ranges, java.util.Collection<java.lang.String> columnFamilies, boolean flushTables) Set up transfer for specific keyspace/ranges/CFs
void	complete() Check if session is completed on receiving StreamMessage.Type.COMPLETE message.
void	convict(java.net.InetAddress endpoint, double phi) Convict the specified endpoint.
java.lang.String	description()
void	doRetry(FileMessageHeader header, java.lang.Throwable e)
void	fileSent(FileMessageHeader header) Call back after sending FileMessageHeader.
SessionInfo	getSessionInfo()
void	init(StreamResultFuture streamResult) Bind this session to report to specific StreamResultFuture and perform pre-streaming initialization.
boolean	isSuccess() Return if this session completed successfully.
void	messageReceived(StreamMessage message)
void	onAlive(java.net.InetAddress endpoint, EndpointState state)
void	onChange(java.net.InetAddress endpoint, ApplicationState state, VersionedValue value)
void	onDead(java.net.InetAddress endpoint, EndpointState state)
void	onError(java.lang.Throwable e) Call back for handling exception during streaming.
void	onInitializationComplete() Call back when connection initialization is complete to start the prepare phase.
void	onJoin(java.net.InetAddress endpoint, EndpointState epState) Use to inform interested parties about the change in the state for specified endpoint
void	onRemove(java.net.InetAddress endpoint)
void	onRestart(java.net.InetAddress endpoint, EndpointState epState) Called whenever a node is restarted.
java.util.UUID	planId()
void	prepare(java.util.Collection<StreamRequest> requests, java.util.Collection<StreamSummary> summaries) Prepare this session for sending/receiving files.
void	progress(Descriptor desc, ProgressInfo.Direction direction, long bytes, long total)
void	receive(FileMessage message) Call back after receiving FileMessageHeader.
void	received(java.util.UUID cfId, int sequenceNumber)
void	retry(java.util.UUID cfId, int sequenceNumber) Call back on receiving StreamMessage.Type.RETRY message.
void	sessionFailed() Call back on receiving StreamMessage.Type.SESSION_FAILED message.
void	start()
StreamSession.State	state()
void	state(StreamSession.State newState) Set current state to newState.
void	taskCompleted(StreamReceiveTask completedTask)
void	taskCompleted(StreamTransferTask completedTask)

Methods inherited from class java.lang.Object

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

Field Detail

peer

public final java.net.InetAddress peer

handler

public final ConnectionHandler handler

Constructor Detail

StreamSession

public StreamSession(java.net.InetAddress peer)

Create new streaming session with the peer.

Parameters:

peer - Address of streaming peer

Method Detail

planId

public java.util.UUID planId()

description

public java.lang.String description()

init

public void init(StreamResultFuture streamResult)

Bind this session to report to specific StreamResultFuture and perform pre-streaming initialization.

Parameters:

streamResult - result to report to

start

public void start()

addStreamRequest

public void addStreamRequest(java.lang.String keyspace,
                    java.util.Collection<Range<Token>> ranges,
                    java.util.Collection<java.lang.String> columnFamilies)

Request data fetch task to this session.

Parameters:

keyspace - Requesting keyspace

ranges - Ranges to retrieve data

columnFamilies - ColumnFamily names. Can be empty if requesting all CF under the keyspace.

addTransferRanges

public void addTransferRanges(java.lang.String keyspace,
                     java.util.Collection<Range<Token>> ranges,
                     java.util.Collection<java.lang.String> columnFamilies,
                     boolean flushTables)

Set up transfer for specific keyspace/ranges/CFs

Parameters:

keyspace - Transfer keyspace

ranges - Transfer ranges

columnFamilies - Transfer ColumnFamilies

addTransferFiles

public void addTransferFiles(java.util.Collection<Range<Token>> ranges,
                    java.util.Collection<SSTableReader> sstables)

Set up transfer of the specific SSTables. sstables must be marked as referenced so that not get deleted until transfer completes.

Parameters:

ranges - Transfer ranges

sstables - Transfer files

addTransferFiles

public void addTransferFiles(java.util.Collection<StreamSession.SSTableStreamingSections> sstableDetails)

state

public void state(StreamSession.State newState)

Set current state to newState.

Parameters:

newState - new state to set

state

public StreamSession.State state()

Returns:

current state

isSuccess

public boolean isSuccess()

Return if this session completed successfully.

Returns:

true if session completed successfully.

messageReceived

public void messageReceived(StreamMessage message)

onInitializationComplete

public void onInitializationComplete()

Call back when connection initialization is complete to start the prepare phase.

onError

public void onError(java.lang.Throwable e)

Call back for handling exception during streaming.

Parameters:

e - thrown exception

prepare

public void prepare(java.util.Collection<StreamRequest> requests,
           java.util.Collection<StreamSummary> summaries)

Prepare this session for sending/receiving files.

fileSent

public void fileSent(FileMessageHeader header)

Call back after sending FileMessageHeader.

Parameters:

header - sent header

receive

public void receive(FileMessage message)

Call back after receiving FileMessageHeader.

Parameters:

message - received file

progress

public void progress(Descriptor desc,
            ProgressInfo.Direction direction,
            long bytes,
            long total)

received

public void received(java.util.UUID cfId,
            int sequenceNumber)

retry

public void retry(java.util.UUID cfId,
         int sequenceNumber)

Call back on receiving StreamMessage.Type.RETRY message.

Parameters:

cfId - ColumnFamily ID

sequenceNumber - Sequence number to indicate which file to stream again

complete

public void complete()

Check if session is completed on receiving StreamMessage.Type.COMPLETE message.

sessionFailed

public void sessionFailed()

Call back on receiving StreamMessage.Type.SESSION_FAILED message.

doRetry

public void doRetry(FileMessageHeader header,
           java.lang.Throwable e)

getSessionInfo

public SessionInfo getSessionInfo()

Returns:

Current snapshot of this session info.

taskCompleted

public void taskCompleted(StreamReceiveTask completedTask)

taskCompleted

public void taskCompleted(StreamTransferTask completedTask)

onJoin

public void onJoin(java.net.InetAddress endpoint,
          EndpointState epState)

Description copied from interface: IEndpointStateChangeSubscriber

Use to inform interested parties about the change in the state for specified endpoint

Specified by:

onJoin in interface IEndpointStateChangeSubscriber

Parameters:

endpoint - endpoint for which the state change occurred.

epState - state that actually changed for the above endpoint.

onChange

public void onChange(java.net.InetAddress endpoint,
            ApplicationState state,
            VersionedValue value)

Specified by:

onChange in interface IEndpointStateChangeSubscriber

onAlive

public void onAlive(java.net.InetAddress endpoint,
           EndpointState state)

Specified by:

onAlive in interface IEndpointStateChangeSubscriber

onDead

public void onDead(java.net.InetAddress endpoint,
          EndpointState state)

Specified by:

onDead in interface IEndpointStateChangeSubscriber

onRemove

public void onRemove(java.net.InetAddress endpoint)

Specified by:

onRemove in interface IEndpointStateChangeSubscriber

onRestart

public void onRestart(java.net.InetAddress endpoint,
             EndpointState epState)

Description copied from interface: IEndpointStateChangeSubscriber

Called whenever a node is restarted. Note that there is no guarantee when that happens that the node was previously marked down. It will have only if state.isAlive() == false as state is from before the restarted node is marked up.

Specified by:

onRestart in interface IEndpointStateChangeSubscriber

convict

public void convict(java.net.InetAddress endpoint,
           double phi)

Description copied from interface: IFailureDetectionEventListener

Convict the specified endpoint.

Specified by:

convict in interface IFailureDetectionEventListener

Parameters:

endpoint - endpoint to be convicted

phi - the value of phi with with ep was convicted