diff --git a/ssdb/app.go b/ssdb/app.go
index d9dd0ed..e478e64 100644
--- a/ssdb/app.go
+++ b/ssdb/app.go
@@ -4,6 +4,7 @@ import (
 	"github.com/siddontang/golib/leveldb"
 	"net"
 	"strings"
+	"sync"
 )
 
 type App struct {
@@ -12,6 +13,11 @@ type App struct {
 	listener net.Listener
 
 	db *leveldb.DB
+
+	kvMutex   sync.Mutex
+	hashMutex sync.Mutex
+	listMutex sync.Mutex
+	zsetMutex sync.Mutex
 }
 
 func NewApp(cfg *Config) (*App, error) {
@@ -36,6 +42,8 @@ func NewApp(cfg *Config) (*App, error) {
 		return nil, err
 	}
 
+	app.dbMutex = newKeyMutex(128)
+
 	return app, nil
 }
 
@@ -55,3 +63,7 @@ func (app *App) Run() {
 		newClient(conn, app)
 	}
 }
+
+func (app *App) getMutex(key []byte) *sync.Mutex {
+	return app.dbMutex.Get(key)
+}
diff --git a/ssdb/cmd_kv.go b/ssdb/cmd_kv.go
index 10d9348..5750d58 100644
--- a/ssdb/cmd_kv.go
+++ b/ssdb/cmd_kv.go
@@ -1,54 +1,200 @@
 package ssdb
 
+import (
+	"github.com/siddontang/golib/hack"
+	"strconv"
+)
+
 func getCommand(c *client) error {
+	args := c.args
+	if len(args) != 1 {
+		return ErrCmdParams
+	}
+
+	if v, err := c.app.kv_get(args[0]); err != nil {
+		return err
+	} else {
+		c.writeBulk(v)
+	}
 	return nil
 }
 
 func setCommand(c *client) error {
+	args := c.args
+	if len(args) < 2 {
+		return ErrCmdParams
+	}
+
+	if err := c.app.kv_set(args[0], args[1]); err != nil {
+		return err
+	} else {
+		c.writeStatus(OK)
+	}
+
 	return nil
 }
 
 func getsetCommand(c *client) error {
+	args := c.args
+	if len(args) != 2 {
+		return ErrCmdParams
+	}
+
+	if v, err := c.app.kv_getset(args[0], args[1]); err != nil {
+		return err
+	} else {
+		c.writeBulk(v)
+	}
+
 	return nil
 }
 
 func setnxCommand(c *client) error {
+	args := c.args
+	if len(args) != 2 {
+		return ErrCmdParams
+	}
+
+	if n, err := c.app.kv_setnx(args[0], args[1]); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func existsCommand(c *client) error {
+	args := c.args
+	if len(args) != 1 {
+		return ErrCmdParams
+	}
+
+	if n, err := c.app.kv_exists(args[0]); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func incrCommand(c *client) error {
+	args := c.args
+	if len(args) != 1 {
+		return ErrCmdParams
+	}
+
+	if n, err := c.app.kv_incr(c.args[0], 1); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func decrCommand(c *client) error {
+	args := c.args
+	if len(args) != 1 {
+		return ErrCmdParams
+	}
+
+	if n, err := c.app.kv_incr(c.args[0], -1); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func incrbyCommand(c *client) error {
+	args := c.args
+	if len(args) != 2 {
+		return ErrCmdParams
+	}
+
+	delta, err := strconv.ParseInt(hack.String(args[1]), 10, 64)
+	if err != nil {
+		return err
+	}
+
+	if n, err := c.app.kv_incr(c.args[0], delta); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func decrbyCommand(c *client) error {
+	args := c.args
+	if len(args) != 2 {
+		return ErrCmdParams
+	}
+
+	delta, err := strconv.ParseInt(hack.String(args[1]), 10, 64)
+	if err != nil {
+		return err
+	}
+
+	if n, err := c.app.kv_incr(c.args[0], -delta); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func delCommand(c *client) error {
+	args := c.args
+	if len(args) == 0 {
+		return ErrCmdParams
+	}
+
+	if n, err := c.app.tx_del(args); err != nil {
+		return err
+	} else {
+		c.writeInteger(n)
+	}
+
 	return nil
 }
 
 func msetCommand(c *client) error {
+	args := c.args
+	if len(args) == 0 || len(args)%2 != 0 {
+		return ErrCmdParams
+	}
+
+	if err := c.app.tx_mset(args); err != nil {
+		return err
+	} else {
+		c.writeStatus(OK)
+	}
+
 	return nil
 }
 
-func setexCommand(c *client) error {
-	return nil
-}
+// func setexCommand(c *client) error {
+// 	return nil
+// }
 
 func mgetCommand(c *client) error {
+	args := c.args
+	if len(args) == 0 {
+		return ErrCmdParams
+	}
+
+	if v, err := c.app.kv_mget(args); err != nil {
+		return err
+	} else {
+		c.writeArray(v)
+	}
+
 	return nil
 }
 
@@ -64,6 +210,6 @@ func init() {
 	register("mget", mgetCommand)
 	register("mset", msetCommand)
 	register("set", setCommand)
-	register("setex", setexCommand)
+	//	register("setex", setexCommand)
 	register("setnx", setnxCommand)
 }
diff --git a/ssdb/const.go b/ssdb/const.go
index 541d8bb..00b9b08 100644
--- a/ssdb/const.go
+++ b/ssdb/const.go
@@ -19,3 +19,13 @@ var (
 	PONG = "PONG"
 	OK   = "OK"
 )
+
+const (
+	KV_TYPE byte = iota + 1
+	HASH_TYPE
+	HSIZE_TYPE
+	ZSET_TYPE
+	ZSIZE_TYPE
+	LIST_TYPE
+	LSIZE_TYPE
+)
diff --git a/ssdb/lock.go b/ssdb/lock.go
new file mode 100644
index 0000000..02c2768
--- /dev/null
+++ b/ssdb/lock.go
@@ -0,0 +1,27 @@
+package ssdb
+
+import (
+	"hash/crc32"
+	"sync"
+)
+
+type keyMutex struct {
+	mutexs []*sync.Mutex
+}
+
+func newKeyMutex(size int) *keyMutex {
+	m := new(keyMutex)
+
+	m.mutexs = make([]*sync.Mutex, size)
+
+	for i := range m.mutexs {
+		m.mutexs[i] = &sync.Mutex{}
+	}
+
+	return m
+}
+
+func (k *keyMutex) Get(key []byte) *sync.Mutex {
+	h := int(crc32.ChecksumIEEE(key))
+	return k.mutexs[h%len(k.mutexs)]
+}
diff --git a/ssdb/t_kv.go b/ssdb/t_kv.go
new file mode 100644
index 0000000..96240f7
--- /dev/null
+++ b/ssdb/t_kv.go
@@ -0,0 +1,192 @@
+package ssdb
+
+import (
+	"errors"
+	"github.com/siddontang/golib/hack"
+	"strconv"
+)
+
+var errEmptyKVKey = errors.New("invalid empty kv key")
+var errKVKey = errors.New("invalid encode kv key")
+
+func encode_kv_key(key []byte) []byte {
+	ek := make([]byte, key+1)
+	ek[0] = KV_TYPE
+	copy(ek[1:], key)
+	return ek
+}
+
+func decode_kv_key(encodeKey []byte) ([]byte, error) {
+	if encodeKey[0] != KV_TYPE {
+		return nil, errKVKey
+	}
+
+	return encodeKey[1:], nil
+}
+
+func (a *App) kv_get(key []byte) ([]byte, error) {
+	key = encode_kv_key(key)
+
+	return a.db.Get(key)
+}
+
+func (a *App) kv_set(key []byte, value []byte) error {
+	key = encode_kv_key(key)
+	var err error
+
+	t := a.newTx()
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	t.Put(key, value)
+
+	//todo, binlog
+
+	err = t.Commit()
+
+	return err
+}
+
+func (a *App) kv_getset(key []byte, value []byte) ([]byte, error) {
+	key = encode_kv_key(key)
+	var err error
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	oldValue, _ := a.db.Get(key)
+
+	t := a.newTx()
+
+	t.Put(key, value)
+	//todo, binlog
+
+	err = t.Commit()
+
+	return oldValue, err
+}
+
+func (a *App) kv_setnx(key []byte, value []byte) (int64, error) {
+	key = encode_kv_key(key)
+	var err error
+
+	var n int64 = 1
+
+	t := a.newTx()
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	if v, _ := a.db.Get(key); v != nil {
+		n = 0
+	} else {
+		t.Put(key, value)
+
+		//todo binlog
+
+		err = t.Commit()
+	}
+
+	return n, err
+}
+
+func (a *App) kv_exists(key []byte) (int64, error) {
+	key = encode_kv_key(key)
+	var err error
+
+	var v []byte
+	v, err = a.db.Get(key)
+	if v != nil && err != nil {
+		return 1, nil
+	} else {
+		return 0, err
+	}
+}
+
+func (a *App) kv_incr(key []byte, delta int64) (int64, error) {
+	key = encode_kv_key(key)
+	var err error
+
+	t := a.newTx()
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	var v []byte
+	v, err = a.db.Get(key)
+	if err != nil {
+		return 0, err
+	}
+
+	var n int64 = 0
+	if v != nil {
+		n, err = strconv.ParseInt(hack.String(v), 10, 64)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	n += delta
+
+	t.Put(key, hack.Slice(strconv.FormatInt(n, 10)))
+
+	//todo binlog
+
+	err = t.Commit()
+	return n, err
+}
+
+func (a *App) tx_del(keys [][]byte) (int64, error) {
+	for i := range keys {
+		keys[i] = encode_kv_key(keys[i])
+	}
+
+	t := a.newTx()
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	for i := range keys {
+		t.Delete(keys[i])
+		//todo binlog
+	}
+
+	err := t.Commit()
+	return int64(len(keys)), err
+}
+
+func (a *App) tx_mset(args [][]byte) error {
+	t := a.newTx()
+
+	a.kvMutex.Lock()
+	defer a.kvMutex.Unlock()
+
+	for i := 0; i < len(args); i += 2 {
+		key := encode_kv_key(args[i])
+		value := args[i+1]
+
+		t.Put(key, value)
+
+		//todo binlog
+	}
+
+	err := t.Commit()
+	return err
+}
+
+func (a *App) kv_mget(args [][]byte) ([]interface{}, error) {
+	values := make([]interface{}, len(args))
+
+	for i := range args {
+		key := encode_kv_key(args[i])
+		value, err := a.db.Get(key)
+		if err != nil {
+			return nil, err
+		}
+
+		values[i] = value
+	}
+
+	return values, nil
+}
diff --git a/ssdb/tx.go b/ssdb/tx.go
new file mode 100644
index 0000000..658b034
--- /dev/null
+++ b/ssdb/tx.go
@@ -0,0 +1,39 @@
+package ssdb
+
+import (
+	"github.com/siddontang/golib/leveldb"
+)
+
+type tx struct {
+	app *App
+
+	wb *leveldb.WriteBatch
+}
+
+func (app *App) newTx() *tx {
+	t := new(tx)
+
+	t.app = app
+
+	t.wb = app.db.NewWriteBatch()
+
+	return t
+}
+
+func (t *tx) Put(key []byte, value []byte) {
+	t.wb.Put(key, value)
+}
+
+func (t *tx) Delete(key []byte) {
+	t.wb.Delete(key)
+}
+
+func (t *tx) Commit() error {
+	err := t.wb.Commit()
+	return err
+}
+
+func (t *tx) Rollback() error {
+	err := t.wb.Rollback()
+	return err
+}