import com.google.common.base.Stopwatch;
import java.io.IOException;
import java.util.ArrayList;
+import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.TimeUnit;
* </ul>
*/
public class Follower extends AbstractRaftActorBehavior {
- private static final int SYNC_THRESHOLD = 10;
-
private static final long MAX_ELECTION_TIMEOUT_FACTOR = 18;
private final SyncStatusTracker initialSyncStatusTracker;
private String leaderId;
private short leaderPayloadVersion;
- public Follower(RaftActorContext context) {
+ public Follower(final RaftActorContext context) {
this(context, null, (short)-1);
}
- public Follower(RaftActorContext context, String initialLeaderId, short initialLeaderPayloadVersion) {
+ public Follower(final RaftActorContext context, final String initialLeaderId,
+ final short initialLeaderPayloadVersion) {
super(context, RaftState.Follower);
this.leaderId = initialLeaderId;
this.leaderPayloadVersion = initialLeaderPayloadVersion;
- initialSyncStatusTracker = new SyncStatusTracker(context.getActor(), getId(), SYNC_THRESHOLD);
+ initialSyncStatusTracker = new SyncStatusTracker(context.getActor(), getId(), context.getConfigParams()
+ .getSyncIndexThreshold());
if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
actor().tell(TimeoutNow.INSTANCE, actor());
}
@VisibleForTesting
- protected final void setLeaderPayloadVersion(short leaderPayloadVersion) {
+ protected final void setLeaderPayloadVersion(final short leaderPayloadVersion) {
this.leaderPayloadVersion = leaderPayloadVersion;
}
lastLeaderMessageTimer.start();
}
- private boolean isLogEntryPresent(long index) {
+ private boolean isLogEntryPresent(final long index) {
if (context.getReplicatedLog().isInSnapshot(index)) {
return true;
}
}
- private void updateInitialSyncStatus(long currentLeaderCommit, String newLeaderId) {
+ private void updateInitialSyncStatus(final long currentLeaderCommit, final String newLeaderId) {
initialSyncStatusTracker.update(newLeaderId, currentLeaderCommit, context.getCommitIndex());
}
@Override
- protected RaftActorBehavior handleAppendEntries(ActorRef sender, AppendEntries appendEntries) {
+ protected RaftActorBehavior handleAppendEntries(final ActorRef sender, final AppendEntries appendEntries) {
int numLogEntries = appendEntries.getEntries() != null ? appendEntries.getEntries().size() : 0;
if (log.isTraceEnabled()) {
leaderId = appendEntries.getLeaderId();
leaderPayloadVersion = appendEntries.getPayloadVersion();
- updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
// First check if the logs are in sync or not
long lastIndex = lastIndex();
lastTerm(), context.getPayloadVersion());
log.info("{}: Follower is out-of-sync so sending negative reply: {}", logName(), reply);
-
+ updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
sender.tell(reply, actor());
return this;
}
// follower's log and state.
log.info("{}: Could not remove entries - sending reply to force snapshot", logName());
+ updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
lastTerm(), context.getPayloadVersion(), true), actor());
return this;
break;
} else {
+ updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
lastTerm(), context.getPayloadVersion(), true), actor());
return this;
}
// Reply to the leader before applying any previous state so as not to hold up leader consensus.
+ updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
sender.tell(reply, actor());
// If commitIndex > lastApplied: increment lastApplied, apply
if (appendEntries.getLeaderCommit() > context.getLastApplied()
&& context.getLastApplied() < lastIndex) {
if (log.isDebugEnabled()) {
- log.debug("{}: applyLogToStateMachine, appendEntries.getLeaderCommit(): {},"
+ log.debug("{}: applyLogToStateMachine, appendEntries.getLeaderCommit(): {}, "
+ "context.getLastApplied(): {}, lastIndex(): {}", logName(),
appendEntries.getLeaderCommit(), context.getLastApplied(), lastIndex);
}
return this;
}
- private boolean isOutOfSync(AppendEntries appendEntries) {
-
- long prevLogTerm = getLogEntryTerm(appendEntries.getPrevLogIndex());
- boolean prevEntryPresent = isLogEntryPresent(appendEntries.getPrevLogIndex());
- long lastIndex = lastIndex();
- int numLogEntries = appendEntries.getEntries() != null ? appendEntries.getEntries().size() : 0;
- boolean outOfSync = true;
+ private boolean isOutOfSync(final AppendEntries appendEntries) {
+ final long lastIndex = lastIndex();
if (lastIndex == -1 && appendEntries.getPrevLogIndex() != -1) {
- // The follower's log is out of sync because the leader does have
- // an entry at prevLogIndex and this follower has no entries in
- // it's log.
-
- log.info("{}: The followers log is empty and the senders prevLogIndex is {}",
- logName(), appendEntries.getPrevLogIndex());
- } else if (lastIndex > -1 && appendEntries.getPrevLogIndex() != -1 && !prevEntryPresent) {
-
- // The follower's log is out of sync because the Leader's
- // prevLogIndex entry was not found in it's log
-
- log.info("{}: The log is not empty but the prevLogIndex {} was not found in it - "
- + "lastIndex: {}, snapshotIndex: {}", logName(), appendEntries.getPrevLogIndex(), lastIndex,
- context.getReplicatedLog().getSnapshotIndex());
- } else if (lastIndex > -1 && prevEntryPresent && prevLogTerm != appendEntries.getPrevLogTerm()) {
-
- // The follower's log is out of sync because the Leader's
- // prevLogIndex entry does exist in the follower's log but it has
- // a different term in it
-
- log.info("{}: The prevLogIndex {} was found in the log but the term {} is not equal to the append entries"
- + "prevLogTerm {} - lastIndex: {}, snapshotIndex: {}", logName(), appendEntries.getPrevLogIndex(),
- prevLogTerm, appendEntries.getPrevLogTerm(), lastIndex,
- context.getReplicatedLog().getSnapshotIndex());
- } else if (appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
- && appendEntries.getReplicatedToAllIndex() != -1
- && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())) {
- // This append entry comes from a leader who has it's log aggressively trimmed and so does not have
- // the previous entry in it's in-memory journal
-
- log.info("{}: Cannot append entries because the replicatedToAllIndex {} does not appear to be in the"
- + " in-memory journal", logName(), appendEntries.getReplicatedToAllIndex());
- } else if (appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
- && appendEntries.getReplicatedToAllIndex() != -1 && numLogEntries > 0
- && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)) {
- log.info("{}: Cannot append entries because the calculated previousIndex {} was not found in the "
- + " in-memory journal", logName(), appendEntries.getEntries().get(0).getIndex() - 1);
- } else {
- outOfSync = false;
+ // The follower's log is out of sync because the leader does have an entry at prevLogIndex and this
+ // follower has no entries in it's log.
+
+ log.info("{}: The followers log is empty and the senders prevLogIndex is {}", logName(),
+ appendEntries.getPrevLogIndex());
+ return true;
}
- return outOfSync;
+
+ if (lastIndex > -1) {
+ if (isLogEntryPresent(appendEntries.getPrevLogIndex())) {
+ final long prevLogTerm = getLogEntryTerm(appendEntries.getPrevLogIndex());
+ if (prevLogTerm != appendEntries.getPrevLogTerm()) {
+
+ // The follower's log is out of sync because the Leader's prevLogIndex entry does exist
+ // in the follower's log but it has a different term in it
+
+ log.info("{}: The prevLogIndex {} was found in the log but the term {} is not equal to the append "
+ + "entries prevLogTerm {} - lastIndex: {}, snapshotIndex: {}", logName(),
+ appendEntries.getPrevLogIndex(), prevLogTerm, appendEntries.getPrevLogTerm(), lastIndex,
+ context.getReplicatedLog().getSnapshotIndex());
+ return true;
+ }
+ } else if (appendEntries.getPrevLogIndex() != -1) {
+
+ // The follower's log is out of sync because the Leader's prevLogIndex entry was not found in it's log
+
+ log.info("{}: The log is not empty but the prevLogIndex {} was not found in it - lastIndex: {}, "
+ + "snapshotIndex: {}", logName(), appendEntries.getPrevLogIndex(), lastIndex,
+ context.getReplicatedLog().getSnapshotIndex());
+ return true;
+ }
+ }
+
+ if (appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
+ && appendEntries.getReplicatedToAllIndex() != -1) {
+ if (!isLogEntryPresent(appendEntries.getReplicatedToAllIndex())) {
+ // This append entry comes from a leader who has it's log aggressively trimmed and so does not have
+ // the previous entry in it's in-memory journal
+
+ log.info("{}: Cannot append entries because the replicatedToAllIndex {} does not appear to be in the "
+ + "in-memory journal", logName(), appendEntries.getReplicatedToAllIndex());
+ return true;
+ }
+
+ final List<ReplicatedLogEntry> entries = appendEntries.getEntries();
+ if (entries != null && entries.size() > 0 && !isLogEntryPresent(entries.get(0).getIndex() - 1)) {
+ log.info("{}: Cannot append entries because the calculated previousIndex {} was not found in the "
+ + "in-memory journal", logName(), entries.get(0).getIndex() - 1);
+ return true;
+ }
+ }
+
+ return false;
}
@Override
- protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
- AppendEntriesReply appendEntriesReply) {
+ protected RaftActorBehavior handleAppendEntriesReply(final ActorRef sender,
+ final AppendEntriesReply appendEntriesReply) {
return this;
}
@Override
- protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
- RequestVoteReply requestVoteReply) {
+ protected RaftActorBehavior handleRequestVoteReply(final ActorRef sender,
+ final RequestVoteReply requestVoteReply) {
return this;
}
@Override
- public RaftActorBehavior handleMessage(ActorRef sender, Object message) {
+ public RaftActorBehavior handleMessage(final ActorRef sender, final Object message) {
if (message instanceof ElectionTimeout || message instanceof TimeoutNow) {
return handleElectionTimeout(message);
}
return super.handleMessage(sender, rpc);
}
- private RaftActorBehavior handleElectionTimeout(Object message) {
+ private RaftActorBehavior handleElectionTimeout(final Object message) {
// If the message is ElectionTimeout, verify we haven't actually seen a message from the leader
// during the election timeout interval. It may that the election timer expired b/c this actor
// was busy and messages got delayed, in which case leader messages would be backed up in the
return false;
}
- private void handleInstallSnapshot(final ActorRef sender, InstallSnapshot installSnapshot) {
+ private void handleInstallSnapshot(final ActorRef sender, final InstallSnapshot installSnapshot) {
log.debug("{}: handleInstallSnapshot: {}", logName(), installSnapshot);
Code Review / controller.git / blobdiff