com.bigdata.ha

Interface QuorumPipeline<S extends HAPipelineGlue>

All Known Subinterfaces:

QuorumService<S>

All Known Implementing Classes:

QuorumPipelineImpl, QuorumServiceBase

public interface QuorumPipeline<S extends HAPipelineGlue>

A non-remote interface for a member service in a Quorum defining methods to replicating writes.

Version:

$Id$

Author:

Bryan Thompson

Method Summary

Methods

Modifier and Type	Method and Description
long	getLastCommitCounter() Return the lastCommitCounter for this service (based on its current root block).
long	getLastCommitTime() Return the lastCommitTime for this service (based on its current root block).
UUID	getStoreUUID() The UUID of the backing store.
void	logRootBlock(IRootBlockView rootBlock) Log the root block for the commit point that closes the current write set onto the HALogWriter.
void	logWriteCacheBlock(IHAWriteMessage msg, ByteBuffer data) Log the IHAWriteMessage and the associated data (if necessary).
void	purgeHALogs(long token) Purge the local HA log files.
Future<Void>	receiveAndReplicate(IHASyncRequest req, IHASendState snd, IHAWriteMessage msg) Return a Future for a task which will replicate an NIO buffer along the write pipeline.
Future<Void>	replicate(IHASyncRequest req, IHAWriteMessage msg, ByteBuffer b) Return a Future for a task which will replicate an NIO buffer along the write pipeline.
Future<IHAPipelineResetResponse>	resetPipeline(IHAPipelineResetRequest req) Reset the pipeline (blocking).

Method Detail

replicate

Future<Void> replicate(IHASyncRequest req,
                     IHAWriteMessage msg,
                     ByteBuffer b)
                       throws IOException

Return a Future for a task which will replicate an NIO buffer along the write pipeline. This method is only invoked by the quorum leader. The payload is replicated to the first follower in the write pipeline. That follower will accept the payload (and replicate it if necessary) using #receiveAndReplicate(IHAWriteMessage).

Note: The implementation of this method should be robust to changes in the write pipeline. Specifically, if a follower leaves the write pipeline, it should attempt to retransmit the message and the payload while allowing time for the write pipeline to be reconfigured in response to the related QuorumMember events.

Parameters:

req - A synchronization request (optional). This is only non-null when historical WriteCache blocks are being replayed down the write pipeline in order to synchronize a service.

msg - The RMI metadata about the payload.

b - The payload. The bytes from the position to the limit will be transmitted (note that the #of bytes remaining in the buffer MUST agree with IHAWriteMessageBase.getSize()).

Throws:

IOException

receiveAndReplicate

Future<Void> receiveAndReplicate(IHASyncRequest req,
                               IHASendState snd,
                               IHAWriteMessage msg)
                                 throws IOException

Return a Future for a task which will replicate an NIO buffer along the write pipeline. This method is invoked for any node except the master, including the last node in the failover chain.

Parameters:

req - A synchronization request (optional). This is only non-null when historical WriteCache blocks are being replayed down the write pipeline in order to synchronize a service.

snd - Metadata about the state of the sender and potentially the routing of the payload along the write replication pipeline.

msg - The RMI metadata about the payload.

Throws:

IOException

resetPipeline

Future<IHAPipelineResetResponse> resetPipeline(IHAPipelineResetRequest req)
                                               throws IOException

Reset the pipeline (blocking). This message is used to handle an error in pipeline replication. If replication fails, the socket connections both upstream and downstream of the point of failure can be left in an indeterminate state with partially buffered data. In order to bring the pipeline back into a known state (without forcing a quorum break) we message each service in the pipeline to reset its HAReceiveService (including the inner HASendService). The next message and payload relayed from the leader will cause new socket connections to be established.

Parameters:

msg - The request.

Returns:

The Future for the operation on the local service.

Throws:

IOException

getLastCommitTime

long getLastCommitTime()

Return the lastCommitTime for this service (based on its current root block). This supports the IHAWriteMessage which requires this information as part of the metadata about replicated WriteCache blocks.

getLastCommitCounter

long getLastCommitCounter()

Return the lastCommitCounter for this service (based on its current root block). This supports the IHAWriteMessage which requires this information as part of the metadata about replicated WriteCache blocks.

getStoreUUID

UUID getStoreUUID()

The UUID of the backing store.

logWriteCacheBlock

void logWriteCacheBlock(IHAWriteMessage msg,
                      ByteBuffer data)
                        throws IOException

Log the IHAWriteMessage and the associated data (if necessary). The log file for the current write set will be deleted if the quorum is fully met at the next 2-phase commit.

Parameters:

msg - The IHAWriteMessage.

data - The WriteCache block.

Throws:

IOException

logRootBlock

void logRootBlock(IRootBlockView rootBlock)
                  throws IOException

Log the root block for the commit point that closes the current write set onto the HALogWriter.

Note: This method is ONLY invoked as part of the 2-phase commit protocol. Therefore, this method ONLY applies to the live HALog file. A service is atomically either joined with the met quorum at a 2-phase commit point or not joined. The PREPARE and COMMIT messages are ONLY generated for services that were joined with the met quorum as of that atomic decision point in the commit protocol. Therefore, this method is never called for a service that was not joined as of that atomic decision point.

Parameters:

rootBlock - The root block for the commit point that was just achieved.

Throws:

IOException

purgeHALogs

void purgeHALogs(long token)

Purge the local HA log files. This should be invoked when the service goes through a commit point in which the quorum is fully met. At that moment, we no longer require these log files to resynchronize any service.

Note: The open HALog file is NOT removed by this method.

Parameters:

token - The quorum token. The quorum must remain fully met for this token across this operation. If that invariant is violated then the operation will terminate once this violation is noticed.