raft: use entryID in raftLog.stableTo

Signed-off-by: Pavel Kalinnikov <pavel@cockroachlabs.com>

Author: pav-kv

log.go

@@ -364,7 +364,7 @@ func (l *raftLog) acceptApplying(i uint64, size entryEncodingSize, allowUnstable
 		i < l.maxAppliableIndex(allowUnstable)
 }
 
-func (l *raftLog) stableTo(i, t uint64) { l.unstable.stableTo(i, t) }
+func (l *raftLog) stableTo(id entryID) { l.unstable.stableTo(id) }
 
 func (l *raftLog) stableSnapTo(i uint64) { l.unstable.stableSnapTo(i) }
 

log_test.go

@@ -400,7 +400,7 @@ func TestHasNextCommittedEnts(t *testing.T) {
 
 			raftLog := newLog(storage, raftLogger)
 			raftLog.append(ents...)
-			raftLog.stableTo(4, 1)
+			raftLog.stableTo(entryID{term: 1, index: 4})
 			raftLog.maybeCommit(5, 1)
 			raftLog.appliedTo(tt.applied, 0 /* size */)
 			raftLog.acceptApplying(tt.applying, 0 /* size */, tt.allowUnstable)
@@ -458,7 +458,7 @@ func TestNextCommittedEnts(t *testing.T) {
 
 			raftLog := newLog(storage, raftLogger)
 			raftLog.append(ents...)
-			raftLog.stableTo(4, 1)
+			raftLog.stableTo(entryID{term: 1, index: 4})
 			raftLog.maybeCommit(5, 1)
 			raftLog.appliedTo(tt.applied, 0 /* size */)
 			raftLog.acceptApplying(tt.applying, 0 /* size */, tt.allowUnstable)
@@ -517,7 +517,7 @@ func TestAcceptApplying(t *testing.T) {
 
 			raftLog := newLogWithSize(storage, raftLogger, maxSize)
 			raftLog.append(ents...)
-			raftLog.stableTo(4, 1)
+			raftLog.stableTo(entryID{term: 1, index: 4})
 			raftLog.maybeCommit(5, 1)
 			raftLog.appliedTo(3, 0 /* size */)
 
@@ -566,7 +566,7 @@ func TestAppliedTo(t *testing.T) {
 
 			raftLog := newLogWithSize(storage, raftLogger, maxSize)
 			raftLog.append(ents...)
-			raftLog.stableTo(4, 1)
+			raftLog.stableTo(entryID{term: 1, index: 4})
 			raftLog.maybeCommit(5, 1)
 			raftLog.appliedTo(3, 0 /* size */)
 			raftLog.acceptApplying(5, maxSize+overshoot, false /* allowUnstable */)
@@ -604,7 +604,7 @@ func TestNextUnstableEnts(t *testing.T) {
 
 			ents := raftLog.nextUnstableEnts()
 			if l := len(ents); l > 0 {
-				raftLog.stableTo(ents[l-1].Index, ents[l-1].Term)
+				raftLog.stableTo(entryID{term: ents[l-1].Term, index: ents[l-1].Index})
 			}
 			require.Equal(t, tt.wents, ents)
 			require.Equal(t, previousEnts[len(previousEnts)-1].Index+1, raftLog.unstable.offset)
@@ -655,7 +655,7 @@ func TestStableTo(t *testing.T) {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
 			raftLog := newLog(NewMemoryStorage(), raftLogger)
 			raftLog.append([]pb.Entry{{Index: 1, Term: 1}, {Index: 2, Term: 2}}...)
-			raftLog.stableTo(tt.stablei, tt.stablet)
+			raftLog.stableTo(entryID{term: tt.stablet, index: tt.stablei})
 			require.Equal(t, tt.wunstable, raftLog.unstable.offset)
 		})
 	}
@@ -692,7 +692,7 @@ func TestStableToWithSnap(t *testing.T) {
 			require.NoError(t, s.ApplySnapshot(pb.Snapshot{Metadata: pb.SnapshotMetadata{Index: snapi, Term: snapt}}))
 			raftLog := newLog(s, raftLogger)
 			raftLog.append(tt.newEnts...)
-			raftLog.stableTo(tt.stablei, tt.stablet)
+			raftLog.stableTo(entryID{term: tt.stablet, index: tt.stablei})
 			require.Equal(t, tt.wunstable, raftLog.unstable.offset)
 		})
 

log_unstable.go

@@ -131,30 +131,30 @@ func (u *unstable) acceptInProgress() {
 // The method should only be called when the caller can attest that the entries
 // can not be overwritten by an in-progress log append. See the related comment
 // in newStorageAppendRespMsg.
-func (u *unstable) stableTo(i, t uint64) {
-	gt, ok := u.maybeTerm(i)
+func (u *unstable) stableTo(id entryID) {
+	gt, ok := u.maybeTerm(id.index)
 	if !ok {
 		// Unstable entry missing. Ignore.
-		u.logger.Infof("entry at index %d missing from unstable log; ignoring", i)
+		u.logger.Infof("entry at index %d missing from unstable log; ignoring", id.index)
 		return
 	}
-	if i < u.offset {
+	if id.index < u.offset {
 		// Index matched unstable snapshot, not unstable entry. Ignore.
-		u.logger.Infof("entry at index %d matched unstable snapshot; ignoring", i)
+		u.logger.Infof("entry at index %d matched unstable snapshot; ignoring", id.index)
 		return
 	}
-	if gt != t {
+	if gt != id.term {
 		// Term mismatch between unstable entry and specified entry. Ignore.
 		// This is possible if part or all of the unstable log was replaced
 		// between that time that a set of entries started to be written to
 		// stable storage and when they finished.
 		u.logger.Infof("entry at (index,term)=(%d,%d) mismatched with "+
-			"entry at (%d,%d) in unstable log; ignoring", i, t, i, gt)
+			"entry at (%d,%d) in unstable log; ignoring", id.index, id.term, id.index, gt)
 		return
 	}
-	num := int(i + 1 - u.offset)
+	num := int(id.index + 1 - u.offset)
 	u.entries = u.entries[num:]
-	u.offset = i + 1
+	u.offset = id.index + 1
 	u.offsetInProgress = max(u.offsetInProgress, u.offset)
 	u.shrinkEntriesArray()
 }

log_unstable_test.go

@@ -493,7 +493,7 @@ func TestUnstableStableTo(t *testing.T) {
 				snapshot:         tt.snap,
 				logger:           raftLogger,
 			}
-			u.stableTo(tt.index, tt.term)
+			u.stableTo(entryID{term: tt.term, index: tt.index})
 			require.Equal(t, tt.woffset, u.offset)
 			require.Equal(t, tt.woffsetInProgress, u.offsetInProgress)
 			require.Equal(t, tt.wlen, len(u.entries))

raft.go

@@ -1156,7 +1156,7 @@ func (r *raft) Step(m pb.Message) error {
 
 	case pb.MsgStorageAppendResp:
 		if m.Index != 0 {
-			r.raftLog.stableTo(m.Index, m.LogTerm)
+			r.raftLog.stableTo(entryID{term: m.LogTerm, index: m.Index})
 		}
 		if m.Snapshot != nil {
 			r.appliedSnap(m.Snapshot)

raft_paper_test.go

@@ -923,8 +923,7 @@ func commitNoopEntry(r *raft, s *MemoryStorage) {
 	r.readMessages()
 	s.Append(r.raftLog.nextUnstableEnts())
 	r.raftLog.appliedTo(r.raftLog.committed, 0 /* size */)
-	last := r.raftLog.lastEntryID()
-	r.raftLog.stableTo(last.index, last.term) // TODO(pav-kv): pass lastEntryID directly
+	r.raftLog.stableTo(r.raftLog.lastEntryID())
 }
 
 func acceptAndReply(m pb.Message) pb.Message {

raft_test.go

@@ -33,8 +33,7 @@ import (
 func nextEnts(r *raft, s *MemoryStorage) (ents []pb.Entry) {
 	// Append unstable entries.
 	s.Append(r.raftLog.nextUnstableEnts())
-	last := r.raftLog.lastEntryID()
-	r.raftLog.stableTo(last.index, last.term) // TODO(pav-kv): pass lastEntryID directly
+	r.raftLog.stableTo(r.raftLog.lastEntryID())
 
 	// Run post-append steps.
 	r.advanceMessagesAfterAppend()