db connect once check

db.go

@@ -159,12 +159,7 @@ func ReleaseConfigDB(dbx *DB) {
 	}
 }
 
-func connect() (*sqlx.DB, error) {
-	if db != nil {
-		return db, nil
-	}
-	//*
-	var err error
+func connect() (dbx *sqlx.DB, err error) {
 	once.Do(func() {
 		db, err = sqlx.Connect(config.Driver, config.DNS)
 		if err == nil {
@@ -174,8 +169,8 @@ func connect() (*sqlx.DB, error) {
 			db.Ping()
 		}
 	})
-	//*/
-	return db, err
+	dbx = db
+	return
 }
 
 // Connect connect to database