kvserver: rename Replica.mu.replicaID to Replica.replicaID

The existing behavior is that replicaID is set when creating
a Replica object and does not change.

Release note: None

pkg/kv/kvserver/replica.go

@@ -199,6 +199,11 @@ type Replica struct {
 	log.AmbientContext
 
 	RangeID roachpb.RangeID // Only set by the constructor
+	// The ID of the replica within the Raft group. Only set by the constructor,
+	// so it will not change over the lifetime of this replica. If addressed
+	// under a newer replicaID, the replica immediately replicaGCs itself to
+	// make way for the newer incarnation.
+	replicaID roachpb.ReplicaID
 
 	// The start key of a Range remains constant throughout its lifetime (it does
 	// not change through splits or merges). This field carries a copy of
@@ -516,13 +521,6 @@ type Replica struct {
 		applyingEntries bool
 		// The replica's Raft group "node".
 		internalRaftGroup *raft.RawNode
-		// The ID of the replica within the Raft group. This value may never be 0.
-		// It will not change over the lifetime of this replica. If addressed under
-		// a newer replicaID, the replica immediately replicaGCs itself to make
-		// way for the newer incarnation.
-		// TODO(sumeer): since this is initialized in newUnloadedReplica and never
-		// changed, lift this out of the mu struct.
-		replicaID roachpb.ReplicaID
 		// The minimum allowed ID for this replica. Initialized from
 		// RangeTombstone.NextReplicaID.
 		tombstoneMinReplicaID roachpb.ReplicaID
@@ -715,11 +713,7 @@ func (r *Replica) SafeFormat(w redact.SafePrinter, _ rune) {
 // ReplicaID returns the ID for the Replica. This value is fixed for the
 // lifetime of the Replica.
 func (r *Replica) ReplicaID() roachpb.ReplicaID {
-	// The locking of mu is unnecessary. It will be removed when we lift
-	// replicaID out of the mu struct.
-	r.mu.RLock()
-	defer r.mu.RUnlock()
-	return r.mu.replicaID
+	return r.replicaID
 }
 
 // cleanupFailedProposal cleans up after a proposal that has failed. It
@@ -1320,8 +1314,8 @@ func (r *Replica) assertStateRaftMuLockedReplicaMuRLocked(
 		if !ok {
 			log.Fatalf(ctx, "%+v does not contain local store s%d", r.mu.state.Desc, r.store.StoreID())
 		}
-		if replDesc.ReplicaID != r.mu.replicaID {
-			log.Fatalf(ctx, "replica's replicaID %d diverges from descriptor %+v", r.mu.replicaID, r.mu.state.Desc)
+		if replDesc.ReplicaID != r.replicaID {
+			log.Fatalf(ctx, "replica's replicaID %d diverges from descriptor %+v", r.replicaID, r.mu.state.Desc)
 		}
 	}
 }
@@ -1677,7 +1671,7 @@ func (r *Replica) isNewerThanSplitRLocked(split *roachpb.SplitTrigger) bool {
 		// ID which is above the replica ID of the split then we would not have
 		// written a tombstone but we will have a replica ID that will exceed the
 		// split replica ID.
-		r.mu.replicaID > rightDesc.ReplicaID
+		r.replicaID > rightDesc.ReplicaID
 }
 
 // WatchForMerge is like maybeWatchForMergeLocked, except it expects a merge to

pkg/kv/kvserver/replica_init.go

@@ -72,6 +72,7 @@ func newUnloadedReplica(
 	r := &Replica{
 		AmbientContext: store.cfg.AmbientCtx,
 		RangeID:        desc.RangeID,
+		replicaID:      replicaID,
 		creationTime:   timeutil.Now(),
 		store:          store,
 		abortSpan:      abortspan.New(desc.RangeID),
@@ -93,7 +94,6 @@ func newUnloadedReplica(
 	r.mu.stateLoader = stateloader.Make(desc.RangeID)
 	r.mu.quiescent = true
 	r.mu.conf = store.cfg.DefaultSpanConfig
-	r.mu.replicaID = replicaID
 	split.Init(&r.loadBasedSplitter, rand.Intn, func() float64 {
 		return float64(SplitByLoadQPSThreshold.Get(&store.cfg.Settings.SV))
 	}, func() time.Duration {
@@ -179,7 +179,7 @@ func (r *Replica) loadRaftMuLockedReplicaMuLocked(desc *roachpb.RangeDescriptor)
 	ctx := r.AnnotateCtx(context.TODO())
 	if r.mu.state.Desc != nil && r.isInitializedRLocked() {
 		log.Fatalf(ctx, "r%d: cannot reinitialize an initialized replica", desc.RangeID)
-	} else if r.mu.replicaID == 0 {
+	} else if r.replicaID == 0 {
 		// NB: This is just a defensive check as r.mu.replicaID should never be 0.
 		log.Fatalf(ctx, "r%d: cannot initialize replica without a replicaID", desc.RangeID)
 	}
@@ -204,15 +204,15 @@ func (r *Replica) loadRaftMuLockedReplicaMuLocked(desc *roachpb.RangeDescriptor)
 
 	// Ensure that we're not trying to load a replica with a different ID than
 	// was used to construct this Replica.
-	replicaID := r.mu.replicaID
+	replicaID := r.replicaID
 	if replicaDesc, found := r.mu.state.Desc.GetReplicaDescriptor(r.StoreID()); found {
 		replicaID = replicaDesc.ReplicaID
 	} else if desc.IsInitialized() {
 		log.Fatalf(ctx, "r%d: cannot initialize replica which is not in descriptor %v", desc.RangeID, desc)
 	}
-	if r.mu.replicaID != replicaID {
+	if r.replicaID != replicaID {
 		log.Fatalf(ctx, "attempting to initialize a replica which has ID %d with ID %d",
-			r.mu.replicaID, replicaID)
+			r.replicaID, replicaID)
 	}
 
 	r.setDescLockedRaftMuLocked(ctx, desc)
@@ -346,9 +346,9 @@ func (r *Replica) setDescLockedRaftMuLocked(ctx context.Context, desc *roachpb.R
 	//      store to exist on disk.
 	//   3) Various unit tests do not provide a valid descriptor.
 	replDesc, found := desc.GetReplicaDescriptor(r.StoreID())
-	if found && replDesc.ReplicaID != r.mu.replicaID {
+	if found && replDesc.ReplicaID != r.replicaID {
 		log.Fatalf(ctx, "attempted to change replica's ID from %d to %d",
-			r.mu.replicaID, replDesc.ReplicaID)
+			r.replicaID, replDesc.ReplicaID)
 	}
 
 	// Initialize the tenant. The must be the first time that the descriptor has
@@ -380,7 +380,7 @@ func (r *Replica) setDescLockedRaftMuLocked(ctx context.Context, desc *roachpb.R
 		r.mu.lastReplicaAddedTime = time.Time{}
 	}
 
-	r.rangeStr.store(r.mu.replicaID, desc)
+	r.rangeStr.store(r.replicaID, desc)
 	r.connectionClass.set(rpc.ConnectionClassForKey(desc.StartKey))
 	r.concMgr.OnRangeDescUpdated(desc)
 	r.mu.state.Desc = desc

pkg/kv/kvserver/replica_proposal.go

@@ -257,7 +257,7 @@ func (r *Replica) computeChecksumPostApply(ctx context.Context, cc kvserverpb.Co
 
 		var shouldFatal bool
 		for _, rDesc := range cc.Terminate {
-			if rDesc.StoreID == r.store.StoreID() && rDesc.ReplicaID == r.mu.replicaID {
+			if rDesc.StoreID == r.store.StoreID() && rDesc.ReplicaID == r.replicaID {
 				shouldFatal = true
 			}
 		}
@@ -381,7 +381,7 @@ func (r *Replica) leasePostApplyLocked(
 		}
 	}
 
-	iAmTheLeaseHolder := newLease.Replica.ReplicaID == r.mu.replicaID
+	iAmTheLeaseHolder := newLease.Replica.ReplicaID == r.replicaID
 	// NB: in the case in which a node restarts, minLeaseProposedTS forces it to
 	// get a new lease and we make sure it gets a new sequence number, thus
 	// causing the right half of the disjunction to fire so that we update the

pkg/kv/kvserver/replica_proposal_buf.go

@@ -135,7 +135,7 @@ type proposer interface {
 	locker() sync.Locker
 	rlocker() sync.Locker
 	// The following require the proposer to hold (at least) a shared lock.
-	replicaID() roachpb.ReplicaID
+	getReplicaID() roachpb.ReplicaID
 	destroyed() destroyStatus
 	leaseAppliedIndex() uint64
 	enqueueUpdateCheck()
@@ -395,7 +395,8 @@ func (b *propBuf) FlushLockedWithRaftGroup(
 	if raftGroup != nil {
 		leaderInfo = b.p.leaderStatusRLocked(raftGroup)
 		// Sanity check.
-		if leaderInfo.leaderKnown && leaderInfo.leader == b.p.replicaID() && !leaderInfo.iAmTheLeader {
+		if leaderInfo.leaderKnown && leaderInfo.leader == b.p.getReplicaID() &&
+			!leaderInfo.iAmTheLeader {
 			log.Fatalf(ctx,
 				"inconsistent Raft state: state %s while the current replica is also the lead: %d",
 				raftGroup.BasicStatus().RaftState, leaderInfo.leader)
@@ -531,7 +532,7 @@ func (b *propBuf) FlushLockedWithRaftGroup(
 			// Flush any previously batched (non-conf change) proposals to
 			// preserve the correct ordering or proposals. Later proposals
 			// will start a new batch.
-			if err := proposeBatch(raftGroup, b.p.replicaID(), ents); err != nil {
+			if err := proposeBatch(raftGroup, b.p.getReplicaID(), ents); err != nil {
 				firstErr = err
 				continue
 			}
@@ -581,7 +582,7 @@ func (b *propBuf) FlushLockedWithRaftGroup(
 	if firstErr != nil {
 		return 0, firstErr
 	}
-	return used, proposeBatch(raftGroup, b.p.replicaID(), ents)
+	return used, proposeBatch(raftGroup, b.p.getReplicaID(), ents)
 }
 
 // allocateLAIAndClosedTimestampLocked computes a LAI and closed timestamp to be
@@ -997,8 +998,8 @@ func (rp *replicaProposer) rlocker() sync.Locker {
 	return rp.mu.RWMutex.RLocker()
 }
 
-func (rp *replicaProposer) replicaID() roachpb.ReplicaID {
-	return rp.mu.replicaID
+func (rp *replicaProposer) getReplicaID() roachpb.ReplicaID {
+	return rp.replicaID
 }
 
 func (rp *replicaProposer) destroyed() destroyStatus {

pkg/kv/kvserver/replica_proposal_buf_test.go

@@ -117,7 +117,7 @@ func (t *testProposer) rlocker() sync.Locker {
 	return t.RWMutex.RLocker()
 }
 
-func (t *testProposer) replicaID() roachpb.ReplicaID {
+func (t *testProposer) getReplicaID() roachpb.ReplicaID {
 	return 1
 }
 
@@ -170,7 +170,7 @@ func (t *testProposer) leaderStatusRLocked(raftGroup proposerRaft) rangeLeaderIn
 	var iAmTheLeader, leaderEligibleForLease bool
 	if leaderKnown {
 		leaderRep = roachpb.ReplicaID(raftGroup.BasicStatus().Lead)
-		iAmTheLeader = leaderRep == t.replicaID()
+		iAmTheLeader = leaderRep == t.getReplicaID()
 		repDesc := roachpb.ReplicaDescriptor{
 			ReplicaID: leaderRep,
 			Type:      &t.leaderReplicaType,
@@ -521,9 +521,9 @@ func TestProposalBufferRejectLeaseAcqOnFollower(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			var p testProposer
 			var pc proposalCreator
-			// p.replicaID() is hardcoded; it'd better be hardcoded to what this test
-			// expects.
-			require.Equal(t, self, uint64(p.replicaID()))
+			// p.getReplicaID() is hardcoded; it'd better be hardcoded to what this
+			// test expects.
+			require.Equal(t, self, uint64(p.getReplicaID()))
 
 			var rejected roachpb.ReplicaID
 			if tc.expRejection {

pkg/kv/kvserver/replica_proposal_quota.go

@@ -87,7 +87,7 @@ func (r *Replica) updateProposalQuotaRaftMuLocked(
 
 	status := r.mu.internalRaftGroup.BasicStatus()
 	if r.mu.leaderID != lastLeaderID {
-		if r.mu.replicaID == r.mu.leaderID {
+		if r.replicaID == r.mu.leaderID {
 			// We're becoming the leader.
 			// Initialize the proposalQuotaBaseIndex at the applied index.
 			// After the proposal quota is enabled all entries applied by this replica
@@ -125,7 +125,7 @@ func (r *Replica) updateProposalQuotaRaftMuLocked(
 		}
 		return
 	} else if r.mu.proposalQuota == nil {
-		if r.mu.replicaID == r.mu.leaderID {
+		if r.replicaID == r.mu.leaderID {
 			log.Fatal(ctx, "leader has uninitialized proposalQuota pool")
 		}
 		// We're a follower.

pkg/kv/kvserver/replica_raft.go

@@ -868,7 +868,7 @@ func (r *Replica) handleRaftReadyRaftMuLocked(
 		r.mu.leaderID = leaderID
 		// Clear the remote proposal set. Would have been nil already if not
 		// previously the leader.
-		becameLeader = r.mu.leaderID == r.mu.replicaID
+		becameLeader = r.mu.leaderID == r.replicaID
 	}
 	r.mu.Unlock()
 
@@ -1040,8 +1040,8 @@ func (r *Replica) tick(ctx context.Context, livenessMap liveness.IsLiveMap) (boo
 	// into the local Raft group. The leader won't hit that path, so we update
 	// it whenever it ticks. In effect, this makes sure it always sees itself as
 	// alive.
-	if r.mu.replicaID == r.mu.leaderID {
-		r.mu.lastUpdateTimes.update(r.mu.replicaID, timeutil.Now())
+	if r.replicaID == r.mu.leaderID {
+		r.mu.lastUpdateTimes.update(r.replicaID, timeutil.Now())
 	}
 
 	r.mu.ticks++
@@ -1585,7 +1585,7 @@ func (r *Replica) withRaftGroupLocked(
 		ctx := r.AnnotateCtx(context.TODO())
 		raftGroup, err := raft.NewRawNode(newRaftConfig(
 			raft.Storage((*replicaRaftStorage)(r)),
-			uint64(r.mu.replicaID),
+			uint64(r.replicaID),
 			r.mu.state.RaftAppliedIndex,
 			r.store.cfg,
 			&raftLogger{ctx: ctx},
@@ -1709,7 +1709,7 @@ func (r *Replica) maybeCampaignOnWakeLocked(ctx context.Context) {
 	// method were to be called on an uninitialized replica (which
 	// has no state and thus an empty raft config), this might cause
 	// problems.
-	if _, currentMember := r.mu.state.Desc.GetReplicaDescriptorByID(r.mu.replicaID); !currentMember {
+	if _, currentMember := r.mu.state.Desc.GetReplicaDescriptorByID(r.replicaID); !currentMember {
 		return
 	}
 

pkg/kv/kvserver/replica_raft_quiesce.go

@@ -402,18 +402,18 @@ func shouldReplicaQuiesce(
 func (r *Replica) quiesceAndNotifyRaftMuLockedReplicaMuLocked(
 	ctx context.Context, status *raft.Status, lagging laggingReplicaSet,
 ) bool {
-	fromReplica, fromErr := r.getReplicaDescriptorByIDRLocked(r.mu.replicaID, r.raftMu.lastToReplica)
+	fromReplica, fromErr := r.getReplicaDescriptorByIDRLocked(r.replicaID, r.raftMu.lastToReplica)
 	if fromErr != nil {
 		if log.V(4) {
-			log.Infof(ctx, "not quiescing: cannot find from replica (%d)", r.mu.replicaID)
+			log.Infof(ctx, "not quiescing: cannot find from replica (%d)", r.replicaID)
 		}
 		return false
 	}
 
 	r.quiesceLocked(ctx, lagging)
 
 	for id, prog := range status.Progress {
-		if roachpb.ReplicaID(id) == r.mu.replicaID {
+		if roachpb.ReplicaID(id) == r.replicaID {
 			continue
 		}
 		toReplica, toErr := r.getReplicaDescriptorByIDRLocked(
@@ -444,7 +444,7 @@ func (r *Replica) quiesceAndNotifyRaftMuLockedReplicaMuLocked(
 			curLagging = nil
 		}
 		msg := raftpb.Message{
-			From:   uint64(r.mu.replicaID),
+			From:   uint64(r.replicaID),
 			To:     id,
 			Type:   raftpb.MsgHeartbeat,
 			Term:   status.Term,

pkg/kv/kvserver/replica_raftstorage.go

@@ -895,7 +895,7 @@ func (r *Replica) applySnapshot(
 	// We've cleared all the raft state above, so we are forced to write the
 	// RaftReplicaID again here.
 	if err := r.raftMu.stateLoader.SetRaftReplicaID(
-		ctx, &unreplicatedSST, r.mu.replicaID); err != nil {
+		ctx, &unreplicatedSST, r.replicaID); err != nil {
 		return errors.Wrapf(err, "unable to write RaftReplicaID to unreplicated SST writer")
 	}
 
@@ -1046,7 +1046,7 @@ func (r *Replica) applySnapshot(
 	// we missed the application of a merge) and we are the new leaseholder, we
 	// make sure to update the timestamp cache using the prior read summary to
 	// account for any reads that were served on the right-hand side range(s).
-	if len(subsumedRepls) > 0 && state.Lease.Replica.ReplicaID == r.mu.replicaID && prioReadSum != nil {
+	if len(subsumedRepls) > 0 && state.Lease.Replica.ReplicaID == r.replicaID && prioReadSum != nil {
 		applyReadSummaryToTimestampCache(r.store.tsCache, r.descRLocked(), *prioReadSum)
 	}
 

pkg/kv/kvserver/store_create_replica.go

@@ -98,7 +98,7 @@ func (s *Store) tryGetOrCreateReplica(
 		}
 
 		// The current replica needs to be removed, remove it and go back around.
-		if toTooOld := repl.mu.replicaID < replicaID; toTooOld {
+		if toTooOld := repl.replicaID < replicaID; toTooOld {
 			if shouldLog := log.V(1); shouldLog {
 				log.Infof(ctx, "found message for replica ID %d which is newer than %v",
 					replicaID, repl)
@@ -115,14 +115,14 @@ func (s *Store) tryGetOrCreateReplica(
 		}
 		defer repl.mu.RUnlock()
 
-		if repl.mu.replicaID > replicaID {
+		if repl.replicaID > replicaID {
 			// The sender is behind and is sending to an old replica.
 			// We could silently drop this message but this way we'll inform the
 			// sender that they may no longer exist.
 			repl.raftMu.Unlock()
 			return nil, false, &roachpb.RaftGroupDeletedError{}
 		}
-		if repl.mu.replicaID != replicaID {
+		if repl.replicaID != replicaID {
 			// This case should have been caught by handleToReplicaTooOld.
 			log.Fatalf(ctx, "intended replica id %d unexpectedly does not match the current replica %v",
 				replicaID, repl)

pkg/kv/kvserver/store_raft.go

@@ -388,7 +388,7 @@ func (s *Store) HandleRaftResponse(
 				// that the replica has been removed and re-added quickly. In
 				// that case, we don't want to add it to the replicaGCQueue.
 				// If the replica is not alive then we also should ignore this error.
-				if tErr.ReplicaID != repl.mu.replicaID ||
+				if tErr.ReplicaID != repl.replicaID ||
 					!repl.mu.destroyStatus.IsAlive() ||
 					// Ignore if we want to test the replicaGC queue.
 					s.TestingKnobs().DisableEagerReplicaRemoval {

pkg/kv/kvserver/store_remove_replica.go

@@ -90,7 +90,6 @@ func (s *Store) removeInitializedReplicaRaftMuLocked(
 	// Sanity checks before committing to the removal by setting the
 	// destroy status.
 	var desc *roachpb.RangeDescriptor
-	var replicaID roachpb.ReplicaID
 	{
 		rep.readOnlyCmdMu.Lock()
 		rep.mu.Lock()
@@ -132,11 +131,9 @@ func (s *Store) removeInitializedReplicaRaftMuLocked(
 		// Mark the replica as removed before deleting data.
 		rep.mu.destroyStatus.Set(roachpb.NewRangeNotFoundError(rep.RangeID, rep.StoreID()),
 			destroyReasonRemoved)
-		replicaID = rep.mu.replicaID
 		rep.mu.Unlock()
 		rep.readOnlyCmdMu.Unlock()
 	}
-
 	// Proceed with the removal, all errors encountered from here down are fatal.
 
 	// Another sanity check that this replica is a part of this store.
@@ -150,7 +147,7 @@ func (s *Store) removeInitializedReplicaRaftMuLocked(
 
 	// During merges, the context might have the subsuming range, so we explicitly
 	// log the replica to be removed.
-	log.Infof(ctx, "removing replica r%d/%d", rep.RangeID, replicaID)
+	log.Infof(ctx, "removing replica r%d/%d", rep.RangeID, rep.replicaID)
 
 	s.mu.Lock()
 	if it := s.getOverlappingKeyRangeLocked(desc); it.repl != rep {