diff --git a/ledis/binlog.go b/ledis/binlog.go
index f7f2961..716b11b 100644
--- a/ledis/binlog.go
+++ b/ledis/binlog.go
@@ -263,11 +263,19 @@ func (b *BinLog) Log(args ...[]byte) error {
 	return nil
 }
 
-func (b *BinLog) SavePoint() (string, int64) {
-	if b.logFile == nil {
-		return "", 0
+func (b *BinLog) LogFileName() string {
+	if len(b.logNames) == 0 {
+		return ""
 	} else {
-		st, _ := b.logFile.Stat()
-		return b.logNames[len(b.logNames)-1], st.Size()
+		return b.logNames[len(b.logNames)-1]
+	}
+}
+
+func (b *BinLog) LogFilePos() int64 {
+	if b.logFile == nil {
+		return 0
+	} else {
+		st, _ := b.logFile.Stat()
+		return st.Size()
 	}
 }
diff --git a/ledis/const.go b/ledis/const.go
index 9fecc29..cfe3cd9 100644
--- a/ledis/const.go
+++ b/ledis/const.go
@@ -24,17 +24,21 @@ const (
 	MaxDBNumber uint8 = 16
 
 	//max key size
-	MaxKeySize int = 1<<16 - 1
+	MaxKeySize int = 1024
 
 	//max hash field size
-	MaxHashFieldSize int = 1<<16 - 1
+	MaxHashFieldSize int = 1024
 
 	//max zset member size
-	MaxZSetMemberSize int = 1<<16 - 1
+	MaxZSetMemberSize int = 1024
+
+	//max value size
+	MaxValueSize int = 10 * 1024 * 1024
 )
 
 var (
 	ErrKeySize        = errors.New("invalid key size")
+	ErrValueSize      = errors.New("invalid value size")
 	ErrHashFieldSize  = errors.New("invalid hash field size")
 	ErrZSetMemberSize = errors.New("invalid zset member size")
 )
diff --git a/ledis/ledis.go b/ledis/ledis.go
index 886e69a..8d4d950 100644
--- a/ledis/ledis.go
+++ b/ledis/ledis.go
@@ -93,16 +93,3 @@ func (l *Ledis) Select(index int) (*DB, error) {
 
 	return l.dbs[index], nil
 }
-
-func (l *Ledis) Snapshot() (*leveldb.Snapshot, string, int64) {
-	if l.binlog == nil {
-		return l.ldb.NewSnapshot(), "", 0
-	} else {
-		l.binlog.Lock()
-		s := l.ldb.NewSnapshot()
-		fileName, offset := l.binlog.SavePoint()
-		l.binlog.Unlock()
-
-		return s, fileName, offset
-	}
-}
diff --git a/ledis/t_hash.go b/ledis/t_hash.go
index 2d6550f..bb700c2 100644
--- a/ledis/t_hash.go
+++ b/ledis/t_hash.go
@@ -130,6 +130,8 @@ func (db *DB) hSetItem(key []byte, field []byte, value []byte) (int64, error) {
 func (db *DB) HSet(key []byte, field []byte, value []byte) (int64, error) {
 	if err := checkHashKFSize(key, field); err != nil {
 		return 0, err
+	} else if err := checkValueSize(value); err != nil {
+		return 0, err
 	}
 
 	t := db.hashTx
@@ -166,6 +168,8 @@ func (db *DB) HMset(key []byte, args ...FVPair) error {
 	for i := 0; i < len(args); i++ {
 		if err := checkHashKFSize(key, args[i].Field); err != nil {
 			return err
+		} else if err := checkValueSize(args[i].Value); err != nil {
+			return err
 		}
 
 		ek = db.hEncodeHashKey(key, args[i].Field)
@@ -414,6 +418,11 @@ func (db *DB) HFlush() (drop int64, err error) {
 	for ; it.Valid(); it.Next() {
 		t.Delete(it.Key())
 		drop++
+		if drop%1000 == 0 {
+			if err = t.Commit(); err != nil {
+				return
+			}
+		}
 	}
 
 	err = t.Commit()
diff --git a/ledis/t_kv.go b/ledis/t_kv.go
index c7e228e..9469604 100644
--- a/ledis/t_kv.go
+++ b/ledis/t_kv.go
@@ -19,6 +19,14 @@ func checkKeySize(key []byte) error {
 	return nil
 }
 
+func checkValueSize(value []byte) error {
+	if len(value) > MaxValueSize {
+		return ErrValueSize
+	}
+
+	return nil
+}
+
 func (db *DB) encodeKVKey(key []byte) []byte {
 	ek := make([]byte, len(key)+2)
 	ek[0] = db.index
@@ -137,6 +145,8 @@ func (db *DB) Get(key []byte) ([]byte, error) {
 func (db *DB) GetSet(key []byte, value []byte) ([]byte, error) {
 	if err := checkKeySize(key); err != nil {
 		return nil, err
+	} else if err := checkValueSize(value); err != nil {
+		return nil, err
 	}
 
 	key = db.encodeKVKey(key)
@@ -204,6 +214,8 @@ func (db *DB) MSet(args ...KVPair) error {
 	for i := 0; i < len(args); i++ {
 		if err := checkKeySize(args[i].Key); err != nil {
 			return err
+		} else if err := checkValueSize(args[i].Value); err != nil {
+			return err
 		}
 
 		key = db.encodeKVKey(args[i].Key)
@@ -222,6 +234,8 @@ func (db *DB) MSet(args ...KVPair) error {
 func (db *DB) Set(key []byte, value []byte) error {
 	if err := checkKeySize(key); err != nil {
 		return err
+	} else if err := checkValueSize(value); err != nil {
+		return err
 	}
 
 	var err error
@@ -244,6 +258,8 @@ func (db *DB) Set(key []byte, value []byte) error {
 func (db *DB) SetNX(key []byte, value []byte) (int64, error) {
 	if err := checkKeySize(key); err != nil {
 		return 0, err
+	} else if err := checkValueSize(value); err != nil {
+		return 0, err
 	}
 
 	var err error
@@ -283,6 +299,12 @@ func (db *DB) KvFlush() (drop int64, err error) {
 	for ; it.Valid(); it.Next() {
 		t.Delete(it.Key())
 		drop++
+
+		if drop%1000 == 0 {
+			if err = t.Commit(); err != nil {
+				return
+			}
+		}
 	}
 
 	err = t.Commit()
diff --git a/ledis/t_list.go b/ledis/t_list.go
index 34cbb66..eac2769 100644
--- a/ledis/t_list.go
+++ b/ledis/t_list.go
@@ -398,6 +398,12 @@ func (db *DB) LFlush() (drop int64, err error) {
 	for ; it.Valid(); it.Next() {
 		t.Delete(it.Key())
 		drop++
+		if drop%1000 == 0 {
+			if err = t.Commit(); err != nil {
+				return
+			}
+		}
+
 	}
 
 	err = t.Commit()
diff --git a/ledis/t_zset.go b/ledis/t_zset.go
index 222b4ae..1c86a9e 100644
--- a/ledis/t_zset.go
+++ b/ledis/t_zset.go
@@ -697,6 +697,11 @@ func (db *DB) ZFlush() (drop int64, err error) {
 	for ; it.Valid(); it.Next() {
 		t.Delete(it.Key())
 		drop++
+		if drop%1000 == 0 {
+			if err = t.Commit(); err != nil {
+				return
+			}
+		}
 	}
 
 	err = t.Commit()
diff --git a/ledis/tx.go b/ledis/tx.go
index f5fa7f3..c5aca2d 100644
--- a/ledis/tx.go
+++ b/ledis/tx.go
@@ -33,11 +33,11 @@ func (t *tx) Put(key []byte, value []byte) {
 	t.wb.Put(key, value)
 
 	if t.binlog != nil {
-		buf := make([]byte, 9+len(key)+len(value))
+		buf := make([]byte, 7+len(key)+len(value))
 		buf[0] = BinLogTypeValue
 		pos := 1
-		binary.BigEndian.PutUint32(buf[pos:], uint32(len(key)))
-		pos += 4
+		binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+		pos += 2
 		copy(buf[pos:], key)
 		pos += len(key)
 		binary.BigEndian.PutUint32(buf[pos:], uint32(len(value)))
@@ -52,11 +52,11 @@ func (t *tx) Delete(key []byte) {
 	t.wb.Delete(key)
 
 	if t.binlog != nil {
-		buf := make([]byte, 5+len(key))
+		buf := make([]byte, 3+len(key))
 		buf[0] = BinLogTypeDeletion
 		pos := 1
-		binary.BigEndian.PutUint32(buf[pos:], uint32(len(key)))
-		pos += 4
+		binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+		pos += 2
 		copy(buf[pos:], key)
 
 		t.batch = append(t.batch, buf)