*: address comment

store/localstore/kv.go

@@ -88,7 +88,7 @@ func (s *dbStore) Seek(key []byte) ([]byte, []byte, error) {
 
 // Commit writes the changed data in Batch.
 func (s *dbStore) CommitTxn(txn *dbTxn) error {
-	if len(txn.snapshotVals) == 0 {
+	if len(txn.lockedKeys) == 0 {
 		return nil
 	}
 	c := &command{
@@ -190,7 +190,7 @@ func (s *dbStore) cleanRecentUpdates(segmentIndex int) {
 
 func (s *dbStore) tryLock(txn *dbTxn) (err error) {
 	// check conflict
-	for k := range txn.snapshotVals {
+	for k := range txn.lockedKeys {
 		if _, ok := s.keysLocked[k]; ok {
 			return errors.Trace(kv.ErrLockConflict)
 		}
@@ -206,7 +206,7 @@ func (s *dbStore) tryLock(txn *dbTxn) (err error) {
 	}
 
 	// record
-	for k := range txn.snapshotVals {
+	for k := range txn.lockedKeys {
 		s.keysLocked[k] = txn.tid
 	}
 
@@ -397,11 +397,11 @@ func (s *dbStore) Begin() (kv.Transaction, error) {
 	}
 
 	txn := &dbTxn{
-		tid:          beginVer.Ver,
-		valid:        true,
-		store:        s,
-		version:      kv.MinVersion,
-		snapshotVals: make(map[string]struct{}),
+		tid:        beginVer.Ver,
+		valid:      true,
+		store:      s,
+		version:    kv.MinVersion,
+		lockedKeys: make(map[string]struct{}),
 	}
 	log.Debugf("[kv] Begin txn:%d", txn.tid)
 	txn.UnionStore = kv.NewUnionStore(newSnapshot(s, beginVer))
@@ -449,7 +449,7 @@ func (s *dbStore) newBatch() engine.Batch {
 	return s.db.NewBatch()
 }
 func (s *dbStore) unLockKeys(txn *dbTxn) error {
-	for k := range txn.snapshotVals {
+	for k := range txn.lockedKeys {
 		if tid, ok := s.keysLocked[k]; !ok || tid != txn.tid {
 			debug.PrintStack()
 			log.Fatalf("should never happend:%v, %v", tid, txn.tid)

store/localstore/txn.go

@@ -28,11 +28,11 @@ var (
 // dbTxn is not thread safe
 type dbTxn struct {
 	kv.UnionStore
-	store        *dbStore // for commit
-	tid          uint64
-	valid        bool
-	version      kv.Version          // commit version
-	snapshotVals map[string]struct{} // origin version in snapshot
+	store      *dbStore // for commit
+	tid        uint64
+	valid      bool
+	version    kv.Version          // commit version
+	lockedKeys map[string]struct{} // origin version in snapshot
 }
 
 // Implement transaction interface
@@ -134,7 +134,7 @@ func (txn *dbTxn) Commit() error {
 
 func (txn *dbTxn) close() error {
 	txn.UnionStore.Release()
-	txn.snapshotVals = nil
+	txn.lockedKeys = nil
 	txn.valid = false
 	return nil
 }
@@ -149,7 +149,7 @@ func (txn *dbTxn) Rollback() error {
 
 func (txn *dbTxn) LockKeys(keys ...kv.Key) error {
 	for _, key := range keys {
-		txn.snapshotVals[string(key)] = struct{}{}
+		txn.lockedKeys[string(key)] = struct{}{}
 	}
 	return nil
 }