public void removeFollower(String followerId) {
followerToLog.remove(followerId);
+ mapFollowerToSnapshot.remove(followerId);
}
public void updateMinReplicaCount() {
int replicatedCount = 1;
for (FollowerLogInformation info : followerToLog.values()) {
- if ((info.getMatchIndex() >= N) && (context.getPeerInfo(followerId).isVoting())) {
+ final PeerInfo peerInfo = context.getPeerInfo(info.getId());
+ if(info.getMatchIndex() >= N && (peerInfo != null && peerInfo.isVoting())) {
replicatedCount++;
}
}
if (replicatedCount >= minReplicationCount) {
ReplicatedLogEntry replicatedLogEntry = context.getReplicatedLog().get(N);
- if (replicatedLogEntry != null && replicatedLogEntry.getTerm() == currentTerm()) {
- context.setCommitIndex(N);
- } else {
+ if (replicatedLogEntry == null) {
break;
}
+
+ // Don't update the commit index if the log entry is from a previous term, as per §5.4.1:
+ // "Raft never commits log entries from previous terms by counting replicas".
+ // However we keep looping so we can make progress when new entries in the current term
+ // reach consensus, as per §5.4.1: "once an entry from the current term is committed by
+ // counting replicas, then all prior entries are committed indirectly".
+ if (replicatedLogEntry.getTerm() == currentTerm()) {
+ context.setCommitIndex(N);
+ }
} else {
break;
}
}
}
- private void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
+ protected void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
// Send an AppendEntries to all followers
for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
final String followerId = e.getKey();
appendEntries);
}
- followerActor.tell(appendEntries.toSerializable(), actor());
+ followerActor.tell(appendEntries, actor());
}
/**