PHP 高并发秒杀解决方案

本文提供 PHP 高并发秒杀解决方案（附加三个案例说明（普通流程，使用文件锁，使用redis消息队列））
 
1：（正常流程，不做任何高并发处理），代码如下：

<?php$_mysqli = new mysqli('localhost','root','','secondkill');if (mysqli_connect_errno()) {
echo mysqli_connect_error();
exit();
}
$_mysqli->set_charset('utf8');$_sql = "select stock from goods where id=1";$_result = $_mysqli->query($_sql);$_assoc = $_result->fetch_assoc();if($_assoc['stock']>0){
$_sql = "UPDATE goods SET stock=stock-1 WHERE id=1";
$_mysqli->query($_sql);}$_mysqli->close();?>

2：（使用文件锁），代码如下：

<?php$_mysqli = new mysqli('localhost','root','','secondkill');if (mysqli_connect_errno()) {
echo mysqli_connect_error();
exit();
}
$_mysqli->set_charset('utf8');$_sql = "select stock from goods where id=2";$_result = $_mysqli->query($_sql);$_assoc = $_result->fetch_assoc();$fp = fopen("lock.txt", "w+");
if(!flock($fp,LOCK_EX | LOCK_NB)){
echo "系统繁忙，请稍后再试";
return;
}if($_assoc['stock']>0){
$_sql = "UPDATE goods SET stock=stock-1 WHERE id=2";
if($_mysqli->query($_sql)){
flock($fp,LOCK_UN);//释放锁
}}fclose($fp);
$_mysqli->close();?>

3：使用redis 消息队列，代码如下：

<?php$redis=new Redis();
$result=$redis->connect('127.0.0.1',6379);$_mysqli = new mysqli('localhost','root','','secondkill');if (mysqli_connect_errno()) {
echo mysqli_connect_error();
exit();
}
$_mysqli->set_charset('utf8');/*
for($i=1;$i<=100;$i++){
$redis->lpush('goods_nums',$i); //秒杀开始前，先将库存数量存在队列，配合定时任务，暂定库存为100
}echo $redis->llen('goods_nums');
exit();
*/$check = $redis->lpop('goods_nums');//echo $check;if($check){
echo "秒杀成功";
$_sql = "UPDATE goods SET stock=stock-1 WHERE id=3";
$_mysqli->query($_sql);
return;
} else {
echo "秒杀失败";
}?>