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";
}

?>