PHP的优点之一是速度很快,对于一般的网站应用,可以说是已经足够了。不过如果站点的访问量很高、带宽窄或者其它的因素令服务器产生性能瓶颈的时候,你可能得想想其它的办法来进一步提高PHP的速度了。这篇文章将从几个方面介绍如何做到这一点,从而令用户浏览的时候更加“爽”。
代码优化
在这里并不想再次告诉你
如何写更干净的代码,这一点我想每个人都清楚,在需要速度的时候,你可能已经在PHP源代码的优化上面做了不少的工作,这里所提出的是,这个烦琐的工作可以交由其它工具来完成。这就是Zend Optimizer,此程序可以从Zend Technologies的网站(http://www.zend.com/)免费得到。它的原理很简单,通过检测Zend引擎产生的中间代码,并且优化它来得到更高的执行速度。我认为优化代码是一项颇烦琐的工作,而且优化后的代码可能变得难以理解,尤其是当你放下该PHP程序一段时间后,突然间客户要求你做一些修改时,可能你自己也不懂了;-)。因此我建议你在PHP的源代码较为复杂的时候,用Zend Optimizer来做这个优化的工作,好处是它不会令你的代码变得复杂难懂。
安装Zend Optimizer是非常简单的。只要根据你使用的平台,下载相关的预编译库,并且在你的php.ini中加入两行,重新启动你的web服务器就行了!
zend_optimizer.optimization_level=15zend_extension="/path/to/ZendOptimizer.so" zend_loader.enable=Off
你可能有点奇怪,不是说两行吗,怎么变成三行了。不过第三行是可选的,看来禁止这个zend_loader将会令优化的速度更快,因此不妨在你的php.ini文件中多加这一行。要注意的是:只有在你不使用Zend Encoder Runtime的时候,才可以禁止zend_loader,关于Zend Encoder Runtime,还会在下文提到。
要更快吗?使用cache(缓冲)吧
如果你的PHP应用还需要更快的速度,下一个办法是缓冲。要实现这一点,有几种不同的方式。我自己就试用过Zend Cache(评测版本),APC和Afterburner Cache。
以上提到的都是“缓冲模块”。它们的原理都差不多,在php文件被首次请求的时候,通过将你的PHP源代码的中间代码存储在web服务器的内存中,对于以后同样的请求,都直接提供内存中的“编译”版本。由于它可以令磁盘的访问达到最小化,因此这个方法确实可以极大地提高PHP的性能。更为方便的是,当你的PHP源代码修改时,缓冲的模块可以察觉到这些变化,并且重新载入一样,因此你不必担心客户得到的是旧版本的程序。这些缓冲的模块确实不错,但是我应该选用哪一种呢?下面分别介绍一下:
Zend Cache是Zend Technologies的一个商业化的产品(它也是免费为我们提供PHP引擎和Zend Optimizer的公司)。它确实不错。在首次运行后,你可以明显察觉到PHP的速度得到了很大的提高,服务器的空闲资源也更多了。缺点是你要付费购买它,但就性价比来说,还是非常值得的。
Afterburner Cache是Bware Technologies(bwcache.bware.it)提供的免费缓冲模块。当前还只是beta版,它所做的工作看来与Zend Cache差不多,不过性能的提高就比不上Zend Cache,而且现有的版本不能和Zend Optimizer一起工作,不过它是免费的。
APC(Alternative PHP Cache)是由Community Connect(apc.communityconnect.com)提供的另一个免费模块。它的工作很稳定,速度也有不少的提高,要注意的是,我还没有找到一个官方的测试数据,这些只是在我的应用上作测试,因此不能下一个结论
责任编辑: xintc110

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