phpredis队列实现秒杀

Q1：php+redis消息队列实现抢购功能

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= https://www.jizhuba.com/ajzbdapi/[];$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$data= https://www.jizhuba.com/ajzbdapi/[];$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= https://www.jizhuba.com/ajzbdapi/[];$data['id']= 'null';$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= https://www.jizhuba.com/ajzbdapi/[];$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;}}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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