// データ保持数に達していたら削除
            $query = $app['orm.em']
                ->createQuery(
                    'SELECT count(rp.id) cn FROM Plugin\HSDRelatedProduct\Entity\HSDRelatedProduct rp'
                );
            $rs = $query->getResult();
            if($rs[0]['cn'] > $max_row){
                // 古いrowを削除
                if($rs[0]['cn'] > $max_row){
                    $del_rows = $rs[0]['cn'] - $max_row;
                }
                $stmt = $app['orm.em']->getConnection()->prepare('delete from plg_hsd_related_product order by updated_at asc limit ' . $del_rows);
                $stmt->execute();
            }

                $stmt = $app['orm.em']->getConnection()->prepare('delete from plg_hsd_related_product order by updated_at asc limit ' . $del_rows);
                $stmt->execute();

                $stmt = $app['orm.em']->getConnection()->prepare("
                        SELECT rp.id as id FROM plg_hsd_related_product rp order by updated_at asc limit
                    " . $del_rows);
                $stmt->execute();
                $rs = $stmt->fetchAll();
                foreach($rs as $item){
                    $stmt = $app['orm.em']->getConnection()->prepare('delete from plg_hsd_related_product where id = "' . $item['id'] . '"');
                    $stmt->execute();
                }