php+redis消息队列实现抢购功能
发布:smiling 来源: PHP粉丝网 添加日期:2021-09-03 10:55:45 浏览: 评论:0
本文实例为大家分享了php+redis消息队列实现抢购的具体代码,供大家参考,具体内容如下
实现功能:
1. 基于redis队列,防止高并发的超卖
2. 基于mysql的事务加排它锁,防止高并发的超卖
基于redis队列工作流程:
1. 管理员根据goods表中的库存,创建redis商品库存队列
2. 客户端访问秒杀API
3. web服务器先从redis的商品库存队列中查询剩余库存重点内容
4. redis队列中有剩余,则在mysql中创建订单,去库存,抢购成功
5. redis队列中没有剩余,则提示库存不足,抢购失败重点内容
基于mysql事务和排它锁工作流程:
1. 开启事务
2. 查询库存,并显示的设置写锁(排他锁):SELECT * FROM goods WHERE id = 1 FOR UPDATE
3. 生成订单
4. 去库存,隐示的设置写锁(排他锁):UPDATE goods SET counts = counts – 1 WHERE id = 1
5. commit,释放锁
注意:第二步步可以设置共享锁,不然有可能会造成死锁。
代码:
- <?php
- /**********************************************
- * 抢购模块
- *
- * @author liubin
- * @date 2016-02-10
- *
- * ab -n 1000 -c 100 http://192.168.16.73/Seckill/buy.php
- *
- */
- class seckill extends common
- {
- private $_orderModel = null;
- private $_goodsModel = null;
- private $_redis = null;
- /*
- * 错误信息
- */
- protected $_error = '';
- /**
- * 构造器
- *
- */
- public function __construct()
- {
- if($this->_orderModel === null){
- $this->_orderModel = new OrderModel();
- }
- if($this->_goodsModel === null){
- $this->_goodsModel = new GoodsModel();
- }
- if($this->_redis === null){
- $this->_redis = new QRedis();
- }
- }
- /*
- * 秒杀API
- *
- * @author liubin
- * @date 2017-02-10
- */
- public function addQsec(){
- $gid = intval($_GET['gid']);
- $type = isset($_GET['type']) ? $_GET['type'] : 'mysql';
- switch ($type) {
- case 'mysql':
- $this->order_check_mysql($gid);
- echo $this->getError();
- break;
- case 'redis':
- $this->order_check_redis($gid);
- echo $this->getError();
- break;
- case 'transaction':
- $this->order_check_transaction($gid);
- echo $this->getError();
- break;
- default:
- echo '类型错误';
- break;
- }
- }
- /*
- * 获取错误信息
- *
- * @author liubin
- * @date 2017-02-10
- */
- public function getError(){
- return $this->_error;
- }
- /*
- * 基于mysql验证库存信息
- * @desc 高并发下会导致超卖
- *
- * @author liubin
- * @date 2017-02-10
- */
- protected function order_check_mysql($gid){
- $model = $this->_goodsModel;
- $pdo = $model->getHandler();
- $gid = intval($gid);
- /*
- * 1:$sql_forlock如果不加事务,不加写锁:
- * 超卖非常严重,就不说了
- *
- * 2:$sql_forlock如果不加事务,只加写锁:
- * 第一个会话读$sql_forlock时加写锁,第一个会话$sql_forlock查询结束会释放该行锁.
- * 第二个会话在第一个会话释放后读$sql_forlock的写锁时,会再次$sql_forlock查库存
- * 导致超卖现象产生
- *
- */
- $sql_forlock = 'select * from goods where id = '.$gid .' limit 1 for update';
- //$sql_forlock = 'select * from goods where id = '.$gid .' limit 1';
- $result = $pdo->query($sql_forlock,PDO::FETCH_ASSOC);
- $goodsInfo = $result->fetch();
- if($goodsInfo['counts']>0){
- //去库存
- $gid = $goodsInfo['id'];
- $sql_inventory = 'UPDATE goods SET counts = counts - 1 WHERE id = '.$gid;
- $result = $this->_goodsModel->exect($sql_inventory);
- if($result){
- //创订单
- $data = [];
- $data['order_id'] = $this->_orderModel->buildOrderNo();
- $data['goods_id'] = $goodsInfo['id'];
- $data['addtime'] = time();
- $data['uid'] = 1;
- $order_rs = $this->_orderModel->create_order($data);
- if($order_rs){
- $this->_error = '购买成功';
- return true;
- }
- }
- }
- $this->_error = '库存不足';
- return false;
- }
- /*
- * 基于redis队列验证库存信息
- * @desc Redis是底层是单线程的,命令执行是原子操作,包括lpush,lpop等.高并发下不会导致超卖
- *
- * @author liubin
- * @date 2017-02-10
- */
- protected function order_check_redis($gid){
- $goodsInfo = $this->_goodsModel->getGoods($gid);
- if(!$goodsInfo){
- $this->_error = '商品不存在';
- return false;
- }
- $key = 'goods_list_'.$goodsInfo['id'];
- $count = $this->_redis->getHandel()->lpop($key);
- if(!$count){
- $this->_error = '库存不足';
- return false;
- }
- //生成订单
- $data = [];
- $data['order_id'] = $this->_orderModel->buildOrderNo();
- $data['goods_id'] = $goodsInfo['id'];
- $data['addtime'] = time();
- $data['uid'] = 1;
- $order_rs = $this->_orderModel->create_order($data);
- //库存减少
- $gid = $goodsInfo['id'];
- $sql = 'UPDATE goods SET counts = counts - 1 WHERE id = '.$gid;
- $result = $this->_goodsModel->exect($sql);
- $this->_error = '购买成功';
- return true;
- }
- /*
- * 基于mysql事务验证库存信息
- * @desc 事务 和 行锁 模式,高并发下不会导致超卖,但效率会慢点
- * @author liubin
- * @date 2017-02-10
- 说明:
- 如果$sql_forlock不加写锁,并发时,$sql_forlock查询的记录存都大于0,可以减库存操作.
- 如果$sql_forlock加了写锁,并发时,$sql_forlock查询是等待第一次链接释放后查询.所以库存最多就是5
- */
- protected function order_check_transaction($gid){
- $model = $this->_goodsModel;
- $pdo = $model->getHandler();
- $gid = intval($gid);
- try{
- $pdo->beginTransaction();//开启事务处理
- /*
- * 1:$sql_forlock如果只加事务,不加写锁:
- * 开启事务
- * 因为没有加锁,读$sql_forlock后,并发时$sql_inventory之前还可以再读。
- * $sql_inventory之后和commit之前才会锁定
- * 出现超卖跟事务的一致性不冲突
- *
- *
- * 2:$sql_forlock如果加了事务,又加读锁:
- * 开启事务
- * 第一个会话读$sql_forlock时加读锁,并发时,第二个会话也允许获得$sql_forlock的读锁,
- * 但是在第一个会话执行去库存操作时(写锁),写锁便会等待第二个会话的读锁,第二个会话执行写操作时,写锁便会等待第一个会话的读锁,
- * 出现死锁
- * 3:$sql_forlock如果加了事务,又加写锁:
- * 开启事务
- * 第一个会话读$sql_forlock时加写锁,直到commit才会释放写锁,并发查询不会出现超卖现象。
- *
- */
- $sql_forlock = 'select * from goods where id = '.$gid .' limit 1 for update';
- //$sql_forlock = 'select * from goods where id = '.$gid .' limit 1 LOCK IN SHARE MODE';
- //$sql_forlock = 'select * from goods where id = '.$gid .' limit 1';
- $result = $pdo->query($sql_forlock,PDO::FETCH_ASSOC);
- $goodsInfo = $result->fetch();
- if($goodsInfo['counts']>0){
- //去库存
- $gid = $goodsInfo['id'];
- $sql_inventory = 'UPDATE goods SET counts = counts - 1 WHERE id = '.$gid;
- $result = $this->_goodsModel->exect($sql_inventory);
- if(!$result){
- $pdo->rollBack();
- $this->_error = '库存减少失败';
- return false;
- }
- //创订单
- $data = [];
- $data['id'] = 'null';
- $data['order_id'] = $this->_orderModel->buildOrderNo();
- $data['goods_id'] = $goodsInfo['id'];
- $data['uid'] = 'abc';
- $data['addtime'] = time();
- $sql = 'insert into orders (id,order_id,goods_id,uid,addtime) values ('.$data['id'].',"'.$data['order_id'].'","'.$data['goods_id'].'","'.$data['uid'].'","'.$data['addtime'].'")';
- $result = $pdo->exec($sql);
- if(!$result){
- $pdo->rollBack();
- $this->_error = '订单创建失败';
- return false;
- }
- $pdo->commit();//提交
- $this->_error = '购买成功';
- return true;
- }else{
- $this->_error = '库存不足';
- return false;
- }
- }catch(PDOException $e){
- echo $e->getMessage();
- $pdo->rollBack();
- }
- }
- /*
- * 创建订单
- * mysql 事物处理,也可以用存储过程
- *
- */
- private function create_order($goodsInfo){
- //生成订单
- $data = [];
- $data['order_id'] = $this->_orderModel->buildOrderNo();
- $data['goods_id'] = $goodsInfo['id'];
- $data['addtime'] = time();
- $data['uid'] = 1;
- $order_rs = $this->_orderModel->create_order($data);
- //库存减少
- $gid = $goodsInfo['id'];
- $sql = 'UPDATE goods SET counts = counts - 1 WHERE id = '.$gid;
- $result = $this->_goodsModel->exect($sql);
- return true;
- }
- }
Tags: PHP+Redis 消息队列
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