public function refresh()
    {
        /* @var $cache Cache */
        $cache = is_string($this->db->schemaCache) ? Yii::$app->get($this->db->schemaCache, false) : $this->db->schemaCache;
        if ($this->db->enableSchemaCache && $cache instanceof Cache) {
            TagDependency::invalidate($cache, $this->getCacheTag());
        }
        $this->_indexNames = [];
        $this->_indexes = [];
    }