diff --git a/internal/db/rdb/mysql/mysql.go b/internal/db/rdb/mysql/mysql.go
index 4bf99b46c3f..396a2d0200d 100644
--- a/internal/db/rdb/mysql/mysql.go
+++ b/internal/db/rdb/mysql/mysql.go
@@ -149,9 +149,9 @@ func (m *mySQLClient) Open(ctx context.Context) (err error) {
 func (m *mySQLClient) Ping(ctx context.Context) (err error) {
 	if m.session == nil {
 		err = errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
@@ -186,9 +186,9 @@ func (m *mySQLClient) Ping(ctx context.Context) (err error) {
 func (m *mySQLClient) Close(ctx context.Context) (err error) {
 	if m.session == nil {
 		err = errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
@@ -210,9 +210,9 @@ func (m *mySQLClient) GetVector(ctx context.Context, uuid string) (Vector, error
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return nil, err
 	}
@@ -246,9 +246,9 @@ func (m *mySQLClient) GetIPs(ctx context.Context, uuid string) ([]string, error)
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return nil, err
 	}
@@ -290,6 +290,15 @@ func (m *mySQLClient) SetVector(ctx context.Context, vec Vector) error {
 		return errors.ErrMySQLConnectionClosed
 	}
 
+	if m.session == nil {
+		err := errors.ErrMySQLSessionNil
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
+		)
+		return err
+	}
+
 	tx, err := m.session.Begin()
 	if err != nil {
 		return err
@@ -343,9 +352,9 @@ func (m *mySQLClient) SetVectors(ctx context.Context, vecs ...Vector) error {
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
@@ -406,9 +415,9 @@ func (m *mySQLClient) deleteVector(ctx context.Context, val string) error {
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
@@ -468,9 +477,9 @@ func (m *mySQLClient) SetIPs(ctx context.Context, uuid string, ips ...string) er
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
@@ -510,9 +519,9 @@ func (m *mySQLClient) RemoveIPs(ctx context.Context, ips ...string) error {
 
 	if m.session == nil {
 		err := errors.ErrMySQLSessionNil
-		log.Debugf(
-			"err: %s, { db: %s, host: %s, port: %d, user: %s, pass: %s, name: %s, charset: %s } ",
-			err.Error(), m.db, m.host, m.port, m.user, m.pass, m.name, m.charset,
+		log.Errorf(
+			"err: %s, { db: %s, host: %s, port: %d, user: %s, name: %s, charset: %s } ",
+			err.Error(), m.db, m.host, m.port, m.user, m.name, m.charset,
 		)
 		return err
 	}
diff --git a/internal/db/rdb/mysql/mysql_test.go b/internal/db/rdb/mysql/mysql_test.go
index 07bf816580f..75f4b9fec94 100644
--- a/internal/db/rdb/mysql/mysql_test.go
+++ b/internal/db/rdb/mysql/mysql_test.go
@@ -1458,6 +1458,25 @@ func Test_mySQLClient_SetVector(t *testing.T) {
 				},
 			}
 		}(),
+		func() test {
+			m := new(vector)
+			return test{
+				name: "return error when mysql session is nil",
+				args: args{
+					ctx: context.Background(),
+					mv:  m,
+				},
+				fields: fields{
+					connected: func() (v atomic.Value) {
+						v.Store(true)
+						return
+					}(),
+				},
+				want: want{
+					err: errors.ErrMySQLSessionNil,
+				},
+			}
+		}(),
 		func() test {
 			m := new(vector)
 			err := errors.New("session.Begin error")