diff --git a/ccore/nebula/client_graph.go b/ccore/nebula/client_graph.go
index a39a345..d6b7665 100644
--- a/ccore/nebula/client_graph.go
+++ b/ccore/nebula/client_graph.go
@@ -15,6 +15,7 @@ type (
 		Close() error
 		Factory() Factory
 		Version() Version
+		GetTimezoneInfo() types.TimezoneInfo
 	}
 
 	defaultGraphClient defaultClient
@@ -34,6 +35,10 @@ func NewGraphClient(endpoints []string, username, password string, opts ...Optio
 	return c.Graph(), nil
 }
 
+func (c *defaultGraphClient) GetTimezoneInfo() types.TimezoneInfo {
+	return c.graph.GetTimezoneInfo()
+}
+
 func (c *defaultGraphClient) Open() error {
 	return c.defaultClient().initDriver(func(driver types.Driver) error {
 		return c.graph.open(driver)
diff --git a/ccore/nebula/driver.go b/ccore/nebula/driver.go
index ecc6b42..7022b6b 100644
--- a/ccore/nebula/driver.go
+++ b/ccore/nebula/driver.go
@@ -18,6 +18,7 @@ type (
 		username   string
 		password   string
 		sessionId  int64
+		timezone   types.TimezoneInfo
 	}
 
 	driverMeta struct {
@@ -110,8 +111,13 @@ func (d *driverGraph) open(driver types.Driver) error {
 	return nil
 }
 
+func (d *driverGraph) GetTimezoneInfo() types.TimezoneInfo {
+	return d.timezone
+}
+
 func (d *driverGraph) close() error {
 	if d.GraphClientDriver != nil {
+		d.GraphClientDriver.Signout(d.sessionId)
 		if err := d.GraphClientDriver.Close(); err != nil {
 			return err
 		}
diff --git a/ccore/nebula/gateway/pool/pool.go b/ccore/nebula/gateway/pool/pool.go
index 4045f1a..d4ed1c0 100644
--- a/ccore/nebula/gateway/pool/pool.go
+++ b/ccore/nebula/gateway/pool/pool.go
@@ -55,6 +55,7 @@ type Client struct {
 	updateTime     int64
 	parameterMap   types.ParameterMap
 	account        *Account
+	timezone       types.TimezoneInfo
 }
 
 type ClientInfo struct {
@@ -239,6 +240,7 @@ func NewClient(address string, port int, username string, password string, opts
 			username: username,
 			password: password,
 		},
+		timezone: c.GetTimezoneInfo(),
 	}
 	clientPool[ncid] = client
 	currentClientNum++
@@ -287,7 +289,6 @@ func handleRequest(ncid string) {
 
 				if len(request.Gql) > 0 {
 					// use auth response to get timezone info
-					authResp, err := client.graphClient.Authenticate(client.account.username, client.account.password)
 					if err != nil {
 						if isThriftProtoError(err) || isThriftTransportError(err) {
 							err = fmt.Errorf("%s. %s.\n", err.Error(), InterruptError.Error())
@@ -311,7 +312,7 @@ func handleRequest(ncid string) {
 						return
 					}
 
-					res, err := wrapper.GenResultSet(execResponse, client.graphClient.Factory(), authResp.GetTimezoneInfo())
+					res, err := wrapper.GenResultSet(execResponse, client.graphClient.Factory(), client.timezone)
 					if err != nil {
 						err = fmt.Errorf("%s. %s.\n", err.Error(), InterruptError.Error())
 					}