diff --git a/cmd/ssdb/main.go b/cmd/ssdb/main.go
index 64b50c2..92ba933 100644
--- a/cmd/ssdb/main.go
+++ b/cmd/ssdb/main.go
@@ -5,12 +5,15 @@ import (
 	"github.com/siddontang/go-ssdb/ssdb"
 	"os"
 	"os/signal"
+	"runtime"
 	"syscall"
 )
 
 var configFile = flag.String("config", "", "ssdb config file")
 
 func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
+
 	flag.Parse()
 
 	if len(*configFile) == 0 {
diff --git a/etc/ssdb.json b/etc/ssdb.json
index d0bcd0f..ca79fdf 100644
--- a/etc/ssdb.json
+++ b/etc/ssdb.json
@@ -2,9 +2,9 @@
     "addr": "127.0.0.1:6380",
     "leveldb": {
         "path": "/tmp/ssdb",
-        "compression": true,
+        "compression": false,
         "block_size": 32768,
-        "write_buffer_size": 2097152,
-        "cache_size": 20971520
+        "write_buffer_size": 67108864,
+        "cache_size": 524288000
     }
 }
\ No newline at end of file
diff --git a/ssdb/client.go b/ssdb/client.go
index 8c7b296..999aac9 100644
--- a/ssdb/client.go
+++ b/ssdb/client.go
@@ -23,6 +23,8 @@ type client struct {
 
 	cmd  string
 	args [][]byte
+
+	reqC chan error
 }
 
 func newClient(c net.Conn, app *App) {
@@ -33,6 +35,8 @@ func newClient(c net.Conn, app *App) {
 	co.rb = bufio.NewReaderSize(c, 256)
 	co.wb = bufio.NewWriterSize(c, 256)
 
+	co.reqC = make(chan error, 1)
+
 	go co.run()
 }
 
@@ -52,7 +56,6 @@ func (c *client) run() {
 	for {
 		req, err := c.readRequest()
 		if err != nil {
-			log.Info("read request error %v", err)
 			return
 		}
 
@@ -143,7 +146,10 @@ func (c *client) handleRequest(req [][]byte) {
 		if !ok {
 			err = ErrNotFound
 		} else {
-			err = f(c)
+			go func() {
+				c.reqC <- f(c)
+			}()
+			err = <-c.reqC
 		}
 	}
 
diff --git a/ssdb/cmd_list.go b/ssdb/cmd_list.go
index 4fba6e0..a680a79 100644
--- a/ssdb/cmd_list.go
+++ b/ssdb/cmd_list.go
@@ -91,7 +91,7 @@ func lindexCommand(c *client) error {
 		return err
 	}
 
-	if v, err := c.app.list_index(args[0], index); err != nil {
+	if v, err := c.app.list_index(args[0], int32(index)); err != nil {
 		return err
 	} else {
 		c.writeBulk(v)
@@ -120,7 +120,7 @@ func lrangeCommand(c *client) error {
 		return err
 	}
 
-	if v, err := c.app.list_range(args[0], start, stop); err != nil {
+	if v, err := c.app.list_range(args[0], int32(start), int32(stop)); err != nil {
 		return err
 	} else {
 		c.writeArray(v)
diff --git a/ssdb/cmd_list_test.go b/ssdb/cmd_list_test.go
index a343b93..4f14731 100644
--- a/ssdb/cmd_list_test.go
+++ b/ssdb/cmd_list_test.go
@@ -54,19 +54,11 @@ func testListRange(key []byte, start int64, stop int64, checkValues ...int) erro
 }
 
 func testPrintList(key []byte) {
-	headSeq, _ := testApp.db.GetString(encode_list_key(key, listHeadSeq))
-	tailSeq, _ := testApp.db.GetString(encode_list_key(key, listTailSeq))
-
-	size, _ := testApp.db.GetString(encode_lsize_key(key))
-
-	println("begin ---------------------")
-	println(headSeq, tailSeq, size)
-
 	it := testApp.db.Iterator(encode_list_key(key, listMinSeq),
 		encode_list_key(key, listMaxSeq), 0, 0, -1)
 	for ; it.Valid(); it.Next() {
 		k, seq, _ := decode_list_key(it.Key())
-		println(string(k), seq, string(it.Value()))
+		println(string(k), "seq ", seq, "value:", string(it.Value()))
 	}
 	println("end ---------------------")
 }
diff --git a/ssdb/const.go b/ssdb/const.go
index 93a830f..c2cd1ba 100644
--- a/ssdb/const.go
+++ b/ssdb/const.go
@@ -25,7 +25,7 @@ const (
 	HASH_TYPE
 	HSIZE_TYPE
 	LIST_TYPE
-	LSIZE_TYPE
+	LMETA_TYPE
 	ZSET_TYPE
 	ZSIZE_TYPE
 	ZSCORE_TYPE
diff --git a/ssdb/t_list.go b/ssdb/t_list.go
index 0fd0ad4..7264cb6 100644
--- a/ssdb/t_list.go
+++ b/ssdb/t_list.go
@@ -3,42 +3,40 @@ package ssdb
 import (
 	"encoding/binary"
 	"errors"
-	"github.com/siddontang/golib/hack"
 	"github.com/siddontang/golib/leveldb"
-	"strconv"
 )
 
 const (
-	listHeadSeq int64 = 1
-	listTailSeq int64 = 2
+	listHeadSeq int32 = 1
+	listTailSeq int32 = 2
 
-	listMinSeq     int64 = 1000
-	listMaxSeq     int64 = 1<<63 - 1000
-	listInitialSeq int64 = listMinSeq + (listMaxSeq-listMinSeq)/2
+	listMinSeq     int32 = 1000
+	listMaxSeq     int32 = 1<<31 - 1000
+	listInitialSeq int32 = listMinSeq + (listMaxSeq-listMinSeq)/2
 )
 
-var errLSizeKey = errors.New("invalid lsize key")
+var errLMetaKey = errors.New("invalid lmeta key")
 var errListKey = errors.New("invalid list key")
 var errListSeq = errors.New("invalid list sequence, overflow")
 
-func encode_lsize_key(key []byte) []byte {
+func encode_lmeta_key(key []byte) []byte {
 	buf := make([]byte, len(key)+1)
-	buf[0] = LSIZE_TYPE
+	buf[0] = LMETA_TYPE
 
 	copy(buf[1:], key)
 	return buf
 }
 
-func decode_lsize_key(ek []byte) ([]byte, error) {
-	if len(ek) == 0 || ek[0] != LSIZE_TYPE {
-		return nil, errLSizeKey
+func decode_lmeta_key(ek []byte) ([]byte, error) {
+	if len(ek) == 0 || ek[0] != LMETA_TYPE {
+		return nil, errLMetaKey
 	}
 
 	return ek[1:], nil
 }
 
-func encode_list_key(key []byte, seq int64) []byte {
-	buf := make([]byte, len(key)+13)
+func encode_list_key(key []byte, seq int32) []byte {
+	buf := make([]byte, len(key)+9)
 
 	pos := 0
 	buf[pos] = LIST_TYPE
@@ -50,25 +48,25 @@ func encode_list_key(key []byte, seq int64) []byte {
 	copy(buf[pos:], key)
 	pos += len(key)
 
-	binary.BigEndian.PutUint64(buf[pos:], uint64(seq))
+	binary.BigEndian.PutUint32(buf[pos:], uint32(seq))
 
 	return buf
 }
 
-func decode_list_key(ek []byte) (key []byte, seq int64, err error) {
-	if len(ek) < 13 || ek[0] != LIST_TYPE {
+func decode_list_key(ek []byte) (key []byte, seq int32, err error) {
+	if len(ek) < 9 || ek[0] != LIST_TYPE {
 		err = errListKey
 		return
 	}
 
 	keyLen := int(binary.BigEndian.Uint32(ek[1:]))
-	if keyLen+13 != len(ek) {
+	if keyLen+9 != len(ek) {
 		err = errListKey
 		return
 	}
 
 	key = ek[5 : 5+keyLen]
-	seq = int64(binary.BigEndian.Uint64(ek[5+keyLen:]))
+	seq = int32(binary.BigEndian.Uint32(ek[5+keyLen:]))
 	return
 }
 
@@ -88,108 +86,143 @@ func (a *App) list_rpop(key []byte) ([]byte, error) {
 	return a.list_pop(key, listTailSeq)
 }
 
-func (a *App) list_getSeq(key []byte, whereSeq int64) (int64, error) {
+func (a *App) list_getSeq(key []byte, whereSeq int32) (int64, error) {
 	ek := encode_list_key(key, whereSeq)
 
-	return a.db.GetInt(ek)
+	return Int64(a.db.Get(ek))
+}
+
+func (a *App) list_getMeta(ek []byte) (headSeq int32, tailSeq int32, size int32, err error) {
+	var v []byte
+	v, err = a.db.Get(ek)
+	if err != nil {
+		return
+	} else if v == nil {
+		size = 0
+		return
+	} else {
+		headSeq = int32(binary.LittleEndian.Uint32(v[0:4]))
+		tailSeq = int32(binary.LittleEndian.Uint32(v[4:8]))
+		size = int32(binary.LittleEndian.Uint32(v[8:]))
+	}
+	return
+}
+
+func (a *App) list_setMeta(ek []byte, headSeq int32, tailSeq int32, size int32) {
+	t := a.listTx
+
+	buf := make([]byte, 12)
+
+	binary.LittleEndian.PutUint32(buf[0:4], uint32(headSeq))
+	binary.LittleEndian.PutUint32(buf[4:8], uint32(tailSeq))
+	binary.LittleEndian.PutUint32(buf[8:], uint32(size))
+
+	t.Put(ek, buf)
 }
 
 func (a *App) list_len(key []byte) (int64, error) {
-	ek := encode_lsize_key(key)
-
-	return a.db.GetInt(ek)
+	ek := encode_lmeta_key(key)
+	_, _, size, err := a.list_getMeta(ek)
+	return int64(size), err
 }
 
-func (a *App) list_push(key []byte, args [][]byte, whereSeq int64) (int64, error) {
+func (a *App) list_push(key []byte, args [][]byte, whereSeq int32) (int64, error) {
 	t := a.listTx
 	t.Lock()
 	defer t.Unlock()
 
-	seq, err := a.list_getSeq(key, whereSeq)
+	metaKey := encode_lmeta_key(key)
+	headSeq, tailSeq, size, err := a.list_getMeta(metaKey)
+
 	if err != nil {
 		return 0, err
 	}
 
-	var size int64 = 0
-
-	var delta int64 = 1
+	var delta int32 = 1
+	var seq int32 = 0
 	if whereSeq == listHeadSeq {
 		delta = -1
+		seq = headSeq
+	} else {
+		seq = tailSeq
 	}
 
-	if seq == 0 {
-		seq = listInitialSeq
-
-		t.Put(encode_list_key(key, listHeadSeq), hack.Slice(strconv.FormatInt(seq, 10)))
-		t.Put(encode_list_key(key, listTailSeq), hack.Slice(strconv.FormatInt(seq, 10)))
+	if size == 0 {
+		headSeq = listInitialSeq
+		tailSeq = listInitialSeq
+		seq = headSeq
 	} else {
-		size, err = a.list_len(key)
-		if err != nil {
-			return 0, err
-		}
-
 		seq += delta
 	}
 
 	for i := 0; i < len(args); i++ {
-		t.Put(encode_list_key(key, seq+int64(i)*delta), args[i])
+		t.Put(encode_list_key(key, seq+int32(i)*delta), args[i])
 		//to do add binlog
 	}
 
-	seq += int64(len(args)-1) * delta
+	seq += int32(len(args)-1) * delta
 
 	if seq <= listMinSeq || seq >= listMaxSeq {
 		return 0, errListSeq
 	}
 
-	size += int64(len(args))
+	size += int32(len(args))
 
-	t.Put(encode_lsize_key(key), hack.Slice(strconv.FormatInt(size, 10)))
-	t.Put(encode_list_key(key, whereSeq), hack.Slice(strconv.FormatInt(seq, 10)))
+	if whereSeq == listHeadSeq {
+		headSeq = seq
+	} else {
+		tailSeq = seq
+	}
+
+	a.list_setMeta(metaKey, headSeq, tailSeq, size)
 
 	err = t.Commit()
 
-	return size, err
+	return int64(size), err
 }
 
-func (a *App) list_pop(key []byte, whereSeq int64) ([]byte, error) {
+func (a *App) list_pop(key []byte, whereSeq int32) ([]byte, error) {
 	t := a.listTx
 	t.Lock()
 	defer t.Unlock()
 
-	var delta int64 = 1
-	if whereSeq == listTailSeq {
+	metaKey := encode_lmeta_key(key)
+	headSeq, tailSeq, size, err := a.list_getMeta(metaKey)
+
+	if err != nil {
+		return nil, err
+	}
+
+	var seq int32 = 0
+	var delta int32 = 1
+	if whereSeq == listHeadSeq {
+		seq = headSeq
+	} else {
 		delta = -1
+		seq = tailSeq
 	}
 
-	seq, err := a.list_getSeq(key, whereSeq)
-	if err != nil {
-		return nil, err
-	}
-
+	itemKey := encode_list_key(key, seq)
 	var value []byte
-	value, err = a.db.Get(encode_list_key(key, seq))
+	value, err = a.db.Get(itemKey)
 	if err != nil {
 		return nil, err
 	}
 
-	t.Delete(encode_list_key(key, seq))
+	t.Delete(itemKey)
 	seq += delta
 
-	var size int64
-	size, err = a.list_len(key)
-	if err != nil {
-		return nil, err
-	}
-
 	size--
 	if size <= 0 {
-		t.Delete(encode_lsize_key(key))
-		t.Delete(encode_list_key(key, listHeadSeq))
-		t.Delete(encode_list_key(key, listTailSeq))
+		t.Delete(metaKey)
 	} else {
-		t.Put(encode_list_key(key, whereSeq), hack.Slice(strconv.FormatInt(seq, 10)))
-		t.Put(encode_lsize_key(key), hack.Slice(strconv.FormatInt(size, 10)))
+		if whereSeq == listHeadSeq {
+			headSeq = seq
+		} else {
+			tailSeq = seq
+		}
+
+		a.list_setMeta(metaKey, headSeq, tailSeq, size)
 	}
 
 	//todo add binlog
@@ -197,47 +230,31 @@ func (a *App) list_pop(key []byte, whereSeq int64) ([]byte, error) {
 	return value, err
 }
 
-func (a *App) list_range(key []byte, start int64, stop int64) ([]interface{}, error) {
+func (a *App) list_range(key []byte, start int32, stop int32) ([]interface{}, error) {
 	v := make([]interface{}, 0, 16)
 
-	var startSeq int64
-	var stopSeq int64
+	var startSeq int32
+	var stopSeq int32
 
 	if start > stop {
 		return []interface{}{}, nil
-	} else if start >= 0 && stop >= 0 {
-		seq, err := a.list_getSeq(key, listHeadSeq)
-		if err != nil {
-			return nil, err
-		}
+	}
 
-		startSeq = seq + start
-		stopSeq = seq + stop
+	headSeq, tailSeq, _, err := a.list_getMeta(encode_lmeta_key(key))
+	if err != nil {
+		return nil, err
+	}
 
+	if start >= 0 && stop >= 0 {
+		startSeq = headSeq + start
+		stopSeq = headSeq + stop
 	} else if start < 0 && stop < 0 {
-		seq, err := a.list_getSeq(key, listTailSeq)
-		if err != nil {
-			return nil, err
-		}
-
-		startSeq = seq + start + 1
-		stopSeq = seq + stop + 1
+		startSeq = tailSeq + start + 1
+		stopSeq = tailSeq + stop + 1
 	} else {
 		//start < 0 && stop > 0
-		var err error
-		startSeq, err = a.list_getSeq(key, listTailSeq)
-		if err != nil {
-			return nil, err
-		}
-
-		startSeq += start + 1
-
-		stopSeq, err = a.list_getSeq(key, listHeadSeq)
-		if err != nil {
-			return nil, err
-		}
-
-		stopSeq += stop
+		startSeq = tailSeq + start + 1
+		stopSeq = headSeq + stop
 	}
 
 	if startSeq < listMinSeq {
@@ -257,24 +274,17 @@ func (a *App) list_range(key []byte, start int64, stop int64) ([]interface{}, er
 	return v, nil
 }
 
-func (a *App) list_index(key []byte, index int64) ([]byte, error) {
-	var seq int64
-	var err error
+func (a *App) list_index(key []byte, index int32) ([]byte, error) {
+	var seq int32
+	headSeq, tailSeq, _, err := a.list_getMeta(encode_lmeta_key(key))
+	if err != nil {
+		return nil, err
+	}
+
 	if index >= 0 {
-		seq, err = a.list_getSeq(key, listHeadSeq)
-		if err != nil {
-			return nil, err
-		}
-
-		seq = seq + index
-
+		seq = headSeq + index
 	} else {
-		seq, err = a.list_getSeq(key, listTailSeq)
-		if err != nil {
-			return nil, err
-		}
-
-		seq = seq + index + 1
+		seq = tailSeq + index + 1
 	}
 
 	return a.db.Get(encode_list_key(key, seq))
diff --git a/ssdb/t_zset.go b/ssdb/t_zset.go
index 7de1d9c..290370a 100644
--- a/ssdb/t_zset.go
+++ b/ssdb/t_zset.go
@@ -161,7 +161,7 @@ func (a *App) zset_setItem(key []byte, score int64, member []byte) (int64, error
 	} else if v != nil {
 		exists = 1
 
-		if s, err := strconv.ParseInt(hack.String(v), 10, 64); err != nil {
+		if s, err := Int64(v, err); err != nil {
 			return 0, err
 		} else {
 			sk := encode_zscore_key(key, member, s)
@@ -169,7 +169,7 @@ func (a *App) zset_setItem(key []byte, score int64, member []byte) (int64, error
 		}
 	}
 
-	t.Put(ek, hack.Slice(strconv.FormatInt(score, 10)))
+	t.Put(ek, PutInt64(score))
 
 	sk := encode_zscore_key(key, member, score)
 	t.Put(sk, []byte{})
@@ -190,7 +190,7 @@ func (a *App) zset_delItem(key []byte, member []byte, skipDelScore bool) (int64,
 		//exists
 		if !skipDelScore {
 			//we must del score
-			if s, err := strconv.ParseInt(hack.String(v), 10, 64); err != nil {
+			if s, err := Int64(v, err); err != nil {
 				return 0, err
 			} else {
 				sk := encode_zscore_key(key, member, s)
@@ -233,7 +233,7 @@ func (a *App) zset_add(key []byte, args []interface{}) (int64, error) {
 func (a *App) zset_incrSize(key []byte, delta int64) (int64, error) {
 	t := a.zsetTx
 	sk := encode_zsize_key(key)
-	size, err := a.db.GetInt(sk)
+	size, err := Int64(a.db.Get(sk))
 	if err != nil {
 		return 0, err
 	} else {
@@ -242,7 +242,7 @@ func (a *App) zset_incrSize(key []byte, delta int64) (int64, error) {
 			size = 0
 			t.Delete(sk)
 		} else {
-			t.Put(sk, hack.Slice(strconv.FormatInt(size, 10)))
+			t.Put(sk, PutInt64(size))
 		}
 	}
 
@@ -251,13 +251,18 @@ func (a *App) zset_incrSize(key []byte, delta int64) (int64, error) {
 
 func (a *App) zset_card(key []byte) (int64, error) {
 	sk := encode_zsize_key(key)
-	size, err := a.db.GetInt(sk)
+	size, err := Int64(a.db.Get(sk))
 	return size, err
 }
 
 func (a *App) zset_score(key []byte, member []byte) ([]byte, error) {
 	k := encode_zset_key(key, member)
-	return a.db.Get(k)
+	score, err := Int64(a.db.Get(k))
+	if err != nil {
+		return nil, err
+	}
+
+	return hack.Slice(strconv.FormatInt(score, 10)), nil
 }
 
 func (a *App) zset_rem(key []byte, args [][]byte) (int64, error) {
@@ -293,7 +298,7 @@ func (a *App) zset_incrby(key []byte, delta int64, member []byte) ([]byte, error
 	if err != nil {
 		return nil, err
 	} else if v != nil {
-		if s, err := strconv.ParseInt(hack.String(v), 10, 64); err != nil {
+		if s, err := Int64(v, err); err != nil {
 			return nil, err
 		} else {
 			sk := encode_zscore_key(key, member, s)
@@ -309,13 +314,12 @@ func (a *App) zset_incrby(key []byte, delta int64, member []byte) ([]byte, error
 		a.zset_incrSize(key, 1)
 	}
 
-	buf := hack.Slice(strconv.FormatInt(score, 10))
-	t.Put(ek, buf)
+	t.Put(ek, PutInt64(score))
 
 	t.Put(encode_zscore_key(key, member, score), []byte{})
 
 	err = t.Commit()
-	return buf, err
+	return hack.Slice(strconv.FormatInt(score, 10)), err
 }
 
 func (a *App) zset_count(key []byte, min int64, max int64) (int64, error) {
@@ -342,7 +346,7 @@ func (a *App) zset_rank(key []byte, member []byte, reverse bool) (int64, error)
 	} else if v == nil {
 		return -1, nil
 	} else {
-		if s, err := strconv.ParseInt(hack.String(v), 10, 64); err != nil {
+		if s, err := Int64(v, err); err != nil {
 			return 0, err
 		} else {
 			var it *leveldb.Iterator
diff --git a/ssdb/util.go b/ssdb/util.go
new file mode 100644
index 0000000..61c2b83
--- /dev/null
+++ b/ssdb/util.go
@@ -0,0 +1,29 @@
+package ssdb
+
+import (
+	"encoding/binary"
+	"errors"
+	"github.com/siddontang/golib/hack"
+)
+
+var errIntNumber = errors.New("invalid integer")
+
+func Int64(v []byte, err error) (int64, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil || len(v) == 0 {
+		return 0, nil
+	} else if len(v) != 8 {
+		return 0, errIntNumber
+	}
+
+	return int64(binary.LittleEndian.Uint64(v)), nil
+}
+
+func PutInt64(v int64) []byte {
+	return hack.Int64Slice(v)
+}
+
+func PutInt32(v int32) []byte {
+	return hack.Int32Slice(v)
+}