Interpreted vs. Compiled Languages for Web Sites (PHP, ASP, Perl, Python, etc.)

Question

I build database-driven web sites. Previously I have used Perl or PHP with MySQL.

Now I am starting a big new project, and I want to do it in the way that will result in the most responsive possible site.

I have seen several pages here where questions about how to optimize PHP are criticized with various versions of "it's not worth going to great lengths to optimize PHP since it's an interpreted language and it won't make that much difference".

I have also heard various discussions (especiallon on the SO podcast) about the benefits of compiled vs. interpreted languages, and it seems as though it would be in my interests to use a compiled language to serve up the site instead of an interpreted language.

Is this even possible in a web context? If so, what would be a reasonable language choice?

In addition to speed one benefit I forsee is the possiblity of finding bugs at compile time instead of having to debug the web site. Is this reasonable to expect?

Answer 1

What you can do is what multiple heavy-traffic websites do (like Facebook or Twitter), aka write your "CPU consuming" algorythm in a C-plugin.

For example, you could write a PHP extension if you plan to use PHP, or a Ruby extension if you plan to use Ruby / Ruby on Rails, etc.

That way, you can keep your streamline code simple and easy to maintain (it might be way harder to handle request from C rather than from PHP), while having a strong and solid background core (because it's compiled, and the compiler tells you what the issues are at compile time)

Answer 2

If you were going to build a new language... and you came up with all the semantics and it was complete, and you had some magic box that had a switch between making the language compiled vs. interpreted, the compiled version would be faster than the interpreted version.

Why? Because compiling brings your semantics down to a lower level on the machine which means it can executed much faster, whereas interpreting means the semantics of your language will translated by some thing (i.e. the interpreter) when the user actually uses your site.

Having said that... that doesn't necessarily mean that your site is going to 100% run faster on a compiled language vs an interpreted language. There are interpreters out there that are very fast nowadays for various languages (i.e. PHP), and there are even optimizers for interpreted languages that make them faster even still.

There are many other things that go into the performance of your site that are agnostic of the language you choose. Hardware setup, Database setup, Network topology, etc. These things can have a bigger impact on you. I would suggest measuring to be sure.

For me, finding bugs at compile time is a huge time saver, so I tend to prefer compiled languages which are strongly typed. It lets me get my work done faster, but that doesn't make it objectively the best option. Some people have no issue writing weakly typed code, and running test suites on them to verify their functionality, which I would think would work just as well.