diff --git a/pkg/dbutil/common.go b/pkg/dbutil/common.go
index 306ed30e0..ff54da953 100644
--- a/pkg/dbutil/common.go
+++ b/pkg/dbutil/common.go
@@ -110,6 +110,52 @@ func GetDBConfigFromEnv(schema string) DBConfig {
 	}
 }
 
+type DSNType interface {
+	DSNString() string
+}
+
+type DSNStringType struct {
+	Key   string
+	Value string
+}
+
+func (s DSNStringType) DSNString() string {
+	// key='val'. add single quote for better compatibility.
+	return fmt.Sprintf("&%s=%%27%s%%27", s.Key, url.QueryEscape(s.Value))
+}
+
+type DSNBoolType struct {
+	Key   string
+	Value bool
+}
+
+func (b DSNBoolType) DSNString() string {
+	return fmt.Sprintf("&%s=%t", b.Key, b.Value)
+}
+
+// OpenDB opens a mysql connection FD
+func OpenDBWithDSN(cfg DBConfig, vars []DSNType) (*sql.DB, error) {
+	var dbDSN string
+	if len(cfg.Snapshot) != 0 {
+		log.Info("create connection with snapshot", zap.String("snapshot", cfg.Snapshot))
+		dbDSN = fmt.Sprintf("%s:%s@tcp(%s:%d)/?charset=utf8mb4&tidb_snapshot=%s", cfg.User, cfg.Password, cfg.Host, cfg.Port, cfg.Snapshot)
+	} else {
+		dbDSN = fmt.Sprintf("%s:%s@tcp(%s:%d)/?charset=utf8mb4", cfg.User, cfg.Password, cfg.Host, cfg.Port)
+	}
+
+	for _, dsnType := range vars {
+		dbDSN += dsnType.DSNString()
+	}
+
+	dbConn, err := sql.Open("mysql", dbDSN)
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+
+	err = dbConn.Ping()
+	return dbConn, errors.Trace(err)
+}
+
 // OpenDB opens a mysql connection FD
 func OpenDB(cfg DBConfig, vars map[string]string) (*sql.DB, error) {
 	var dbDSN string
diff --git a/sync_diff_inspector/source/common/conn.go b/sync_diff_inspector/source/common/conn.go
index ad2feff9c..05da79550 100644
--- a/sync_diff_inspector/source/common/conn.go
+++ b/sync_diff_inspector/source/common/conn.go
@@ -22,8 +22,8 @@ import (
 )
 
 // CreateDB creates sql.DB used for select data
-func CreateDB(ctx context.Context, dbConfig *dbutil.DBConfig, vars map[string]string, num int) (db *sql.DB, err error) {
-	db, err = dbutil.OpenDB(*dbConfig, vars)
+func CreateDB(ctx context.Context, dbConfig *dbutil.DBConfig, vars []dbutil.DSNType, num int) (db *sql.DB, err error) {
+	db, err = dbutil.OpenDBWithDSN(*dbConfig, vars)
 	if err != nil {
 		return nil, errors.Errorf("create db connections %s error %v", dbConfig.String(), err)
 	}
diff --git a/sync_diff_inspector/source/source.go b/sync_diff_inspector/source/source.go
index 3bc1db0da..0a6145e25 100644
--- a/sync_diff_inspector/source/source.go
+++ b/sync_diff_inspector/source/source.go
@@ -235,8 +235,8 @@ func buildSourceFromCfg(ctx context.Context, tableDiffs []*common.TableDiff, con
 	return NewMySQLSources(ctx, tableDiffs, dbs, connCount, f)
 }
 
-func getAutoSnapshotPosition(dbConfig *dbutil.DBConfig, vars map[string]string) (string, string, error) {
-	tmpConn, err := dbutil.OpenDB(*dbConfig, vars)
+func getAutoSnapshotPosition(dbConfig *dbutil.DBConfig, vars []dbutil.DSNType) (string, string, error) {
+	tmpConn, err := dbutil.OpenDBWithDSN(*dbConfig, vars)
 	if err != nil {
 		return "", "", errors.Annotatef(err, "connecting to auto-position tidb_snapshot failed")
 	}
@@ -250,9 +250,16 @@ func getAutoSnapshotPosition(dbConfig *dbutil.DBConfig, vars map[string]string)
 }
 
 func initDBConn(ctx context.Context, cfg *config.Config) error {
-	// Unified time zone
-	vars := map[string]string{
-		"time_zone": UnifiedTimeZone,
+	vars := []dbutil.DSNType{
+		// Unified time zone
+		dbutil.DSNStringType{
+			Key:   "time_zone",
+			Value: UnifiedTimeZone,
+		},
+		dbutil.DSNBoolType{
+			Key:   "interpolateParams",
+			Value: true,
+		},
 	}
 
 	// Fill in tidb_snapshot if it is set to AUTO