performance - Why is PHP apt for high-traffic websites?

Question

I was surprised to learn today that PHP is used widely in high-traffic websites.

I always thought that PHP is not strong in terms of performance, being a dynamic, scripting language (e.g. compared to statically typed, compiled language like C/Java/C# etc.).

So how come it performs so well?

Answer 1

What you'll usually find is that it's not as slow as you think. The reason a lot of sites are slow is because the hosts are overloaded.

But one primary benefit of PHP over a compiled language is ease of maintenance. Because PHP is designed from the ground up for HTTP traffic, there's less to build than with most other compiled languages. Plus, merging in changes becomes easier as you don't need to recompile and restart the server (as you would with a compiled binary)...

I've done a considerable amount of benchmarks on both, and for anywhere under about 50k requests per second (based upon my numbers) there really isn't a significant gain to using a compiled binary (FastCGI). Sure, it's a little faster using compiled C, but unless you're talking Facebook level traffic, that's not really going to mean significant $$$. And it's definitely not going to offset the relatively rapid rate of development that PHP will afford in comparison to using C (which more than likely will require many times the code since it's not memory managed)...

PHP, if properly written can be quite scalable. The limiting factors are typically in your database engine. And that's going to be a common factor no matter what technology you use...