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HomeBackend DevelopmentPHP TutorialPHP是单线程的,怎么应对大量的http访问

PHP是单线程的,如何应对大量的http访问?
刚开始只知道php可以做网站,从来没有接触过php的线程问题,今天突然了解到php是单线程的,可是突然想到,php做的网站肯定是用于多人访问的,如果访问量大,那岂不是出现排队问题?
这是真的吗?还是apache在处理php程序的时候会用服务器实现多线程呢?
------解决方案--------------------
PHP确实没有多线程,因此不能在代码里再开一个线程去执行其他任务,不能像java一样,同一时刻有多条主线逻辑在执行.但是这和大访问量并没有多大关系, 因为请求过来,是nginx或apache处理的,然后调用php处理,调用可以是同时进行的,会开启许多要访问脚本的进程,进程与线程是不同的.每个用户都会对应服务器的一个php脚本进程,执行过后(页面被打开),进程就被销毁,内存得到释放.
------解决方案--------------------
所有被启动的 php 解释器都是相互独立的
自然被其解释的 php 代码也是相互独立的

所谓单例,只是对于当前运行的 php 代码集合而言的
------解决方案--------------------

引用:
Quote: 引用:

PHP确实没有多线程,因此不能在代码里再开一个线程去执行其他任务,不能像java一样,同一时刻有多条主线逻辑在执行.但是这和大访问量并没有多大关系, 因为请求过来,是nginx或apache处理的,然后调用php处理,调用可以是同时进行的,会开启许多要访问脚本的进程,进程与线程是不同的.每个用户都会对应服务器的一个php脚本进程,执行过后(页面被打开),进程就被销毁,内存得到释放.

那单例模式中
if($instance == null) {
    $instance = new instance();
}
这块会不会因为服务器调用多个php脚本进行处理,两个调用同时进行了,从而导致new出两个instance呢?


会啊, 单例模式在PHP中只会正对当前运行的脚本, 你也指出了, 是要先检测$instance  是否为空的, 这仅仅局限于本次运行的脚本不会new出多个对象
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