PHP高并发的测试与解决方案（一）常规写法

public function sale_order(){
        $user_id = mt_rand(1,100000);
        $goods_info = Db::name('goods')->where('id',1)->find();
        if($goods_info['goods_num'] <= 0){
            return '商品已售罄';
        }
        $user_info = Db::name('wallet')->where('user_id',$user_id)->find();
        if(empty($user_info)){
            return '用户信息不存在';
        }
        if($user_info['money']<$goods_info['flash_sale_price']){
            return '秒杀失败，余额不足';
        }
        $order_num = $this->get_order_num();
        $order_info = [
            'order_num'     => $order_num,
            'user_id'       => $user_id,
            'goods_id'      => $goods_info['id'],
            'num'           => 1
        ];
        $user_banlance = round(($user_info['money'] - $goods_info['flash_sale_price']),2);
        Db::startTrans();
        try{
            Db::name('goods')->where('id',$goods_info['id'])
                ->setDec('goods_num');
            Db::name('goods_order')->insert($order_info);
            Db::name('wallet')->where('user_id',$user_info['id'])
                ->update(['money'=>$user_banlance]);
            Db::commit();
        }catch (\Exception $e){
            $log_data = [
                'log'   =>   $e->getMessage(),
            ];
            Db::name('log')->insert($log_data);
            Db::rollback();
            return '下单失败';
        }
        return '下单成功';
    }