public function actionOptimize()
 {
     $model = new Database();
     try {
         $model->optimize();
         Yii::$app->session->setFlash('success', Yii::t('System', 'database_optimize_success'));
     } catch (Exception $e) {
         Yii::$app->session->setFlash('error', $e->getMessage());
     }
     return $this->redirect('index');
 }