/**
* Constructs a SyncProposalProcessor object.
*
* @param persistence the persistent variables.
* @param transport used to send acknowledgment.
* @param maxBatchSize the maximum batch size.
* @throws IOException in case of IO failure.
*/
public SyncProposalProcessor(PersistentState persistence, Transport transport, int maxBatchSize)
throws IOException {
this.persistence = persistence;
this.log = persistence.getLog();
this.transport = transport;
this.maxBatchSize = maxBatchSize;
this.serverId = persistence.getLastSeenConfig().getServerId();
ExecutorService es = Executors.newSingleThreadExecutor(DaemonThreadFactory.FACTORY);
ft = es.submit(this);
es.shutdown();
}
@Override
public Void call() throws Exception {
try {
LOG.debug("Batched SyncRequestProcessor gets started.");
MessageTuple lastReq = null;
// Number of transactions batched so far.
int batchCount = 0;
while (true) {
MessageTuple req;
if (lastReq == null) {
req = this.proposalQueue.take();
} else {
req = this.proposalQueue.poll();
if (req == null || batchCount == maxBatchSize || req == MessageTuple.REQUEST_OF_DEATH) {
// Sync to disk and send ACK to leader.
this.log.sync();
Zxid zxid = MessageBuilder.fromProtoZxid(lastReq.getMessage().getProposal().getZxid());
sendAck(lastReq.getServerId(), zxid);
batchCount = 0;
}
}
if (req == MessageTuple.REQUEST_OF_DEATH) {
break;
}
if (req == null) {
lastReq = null;
continue;
}
if (req.getMessage().getType() == MessageType.PROPOSAL) {
// It's PROPOSAL, sync to disk.
Message msg = req.getMessage();
Transaction txn = MessageBuilder.fromProposal(msg.getProposal());
// TODO : avoid this?
ByteBuffer body = txn.getBody().asReadOnlyBuffer();
LOG.debug("Syncing transaction {} to disk.", txn.getZxid());
this.log.append(txn);
batchCount++;
lastReq = req;
if (txn.getType() == ProposalType.COP_VALUE) {
// If it's COP, we should also update cluster_config file.
ClusterConfiguration cnf = ClusterConfiguration.fromByteBuffer(body, this.serverId);
persistence.setLastSeenConfig(cnf);
// If it's COP, we shouldn't batch it, send ACK immediatly.
sendAck(req.getServerId(), txn.getZxid());
batchCount = 0;
lastReq = null;
}
}
}
} catch (Exception e) {
LOG.error("Caught an exception in SyncProposalProcessor", e);
throw e;
}
LOG.debug("SyncProposalProcessor has been shut down.");
return null;
}