Optimise JetStream and Raft locking

server/jetstream_api.go

@@ -4701,9 +4701,13 @@ func (s *Server) jsConsumerInfoRequest(sub *subscription, c *client, _ *Account,
 			return
 		}
 
+		// Since these could wait on the Raft group lock, don't do so under the JS lock.
+		ourID := cc.meta.ID()
+		groupLeader := cc.meta.GroupLeader()
+		groupCreated := cc.meta.Created()
+
 		js.mu.RLock()
 		isLeader, sa, ca := cc.isLeader(), js.streamAssignment(acc.Name, streamName), js.consumerAssignment(acc.Name, streamName, consumerName)
-		ourID := cc.meta.ID()
 		var rg *raftGroup
 		var offline, isMember bool
 		if ca != nil {
@@ -4717,7 +4721,7 @@ func (s *Server) jsConsumerInfoRequest(sub *subscription, c *client, _ *Account,
 		// Also capture if we think there is no meta leader.
 		var isLeaderLess bool
 		if !isLeader {
-			isLeaderLess = cc.meta.GroupLeader() == _EMPTY_ && time.Since(cc.meta.Created()) > lostQuorumIntervalDefault
+			isLeaderLess = groupLeader == _EMPTY_ && time.Since(groupCreated) > lostQuorumIntervalDefault
 		}
 		js.mu.RUnlock()
 

server/jetstream_cluster.go

@@ -902,15 +902,17 @@ func (js *jetStream) server() *Server {
 // Will respond if we do not think we have a metacontroller leader.
 func (js *jetStream) isLeaderless() bool {
 	js.mu.RLock()
-	defer js.mu.RUnlock()
-
 	cc := js.cluster
 	if cc == nil || cc.meta == nil {
+		js.mu.RUnlock()
 		return false
 	}
+	meta := cc.meta
+	js.mu.RUnlock()
+
 	// If we don't have a leader.
 	// Make sure we have been running for enough time.
-	if cc.meta.GroupLeader() == _EMPTY_ && time.Since(cc.meta.Created()) > lostQuorumIntervalDefault {
+	if meta.GroupLeader() == _EMPTY_ && time.Since(meta.Created()) > lostQuorumIntervalDefault {
 		return true
 	}
 	return false
@@ -922,29 +924,32 @@ func (js *jetStream) isGroupLeaderless(rg *raftGroup) bool {
 		return false
 	}
 	js.mu.RLock()
-	defer js.mu.RUnlock()
-
 	cc := js.cluster
+	started := js.started
 
 	// If we are not a member we can not say..
 	if cc.meta == nil {
+		js.mu.RUnlock()
 		return false
 	}
 	if !rg.isMember(cc.meta.ID()) {
+		js.mu.RUnlock()
 		return false
 	}
 	// Single peer groups always have a leader if we are here.
 	if rg.node == nil {
+		js.mu.RUnlock()
 		return false
 	}
+	js.mu.RUnlock()
 	// If we don't have a leader.
 	if rg.node.GroupLeader() == _EMPTY_ {
 		// Threshold for jetstream startup.
 		const startupThreshold = 10 * time.Second
 
 		if rg.node.HadPreviousLeader() {
 			// Make sure we have been running long enough to intelligently determine this.
-			if time.Since(js.started) > startupThreshold {
+			if time.Since(started) > startupThreshold {
 				return true
 			}
 		}
@@ -4487,10 +4492,11 @@ func (js *jetStream) processClusterCreateConsumer(ca *consumerAssignment, state
 	} else {
 		// If we are clustered update the known peers.
 		js.mu.RLock()
-		if node := rg.node; node != nil {
+		node := rg.node
+		js.mu.RUnlock()
+		if node != nil {
 			node.UpdateKnownPeers(ca.Group.Peers)
 		}
-		js.mu.RUnlock()
 	}
 
 	// Check if we already have this consumer running.

server/raft.go

@@ -1674,14 +1674,12 @@ func (n *raft) ID() string {
 	if n == nil {
 		return _EMPTY_
 	}
-	n.RLock()
-	defer n.RUnlock()
+	// Lock not needed as n.id is never changed after creation.
 	return n.id
 }
 
 func (n *raft) Group() string {
-	n.RLock()
-	defer n.RUnlock()
+	// Lock not needed as n.group is never changed after creation.
 	return n.group
 }
 
@@ -1741,8 +1739,7 @@ func (n *raft) QuitC() <-chan struct{} { return n.quit }
 func (n *raft) AppliedFloorC() <-chan struct{} { return n.aflrc }
 
 func (n *raft) Created() time.Time {
-	n.RLock()
-	defer n.RUnlock()
+	// Lock not needed as n.created is never changed after creation.
 	return n.created
 }