CGI Programming with Perl, 2nd Edition

Chapter 17. Efficiency and Optimization

Let’s face it, CGI applications, run under normal conditions, are not exactly speed demons. In this chapter, we will show you a few tricks that you can use to speed up current applications, and also introduce you to two technologies—FastCGI and mod_perl —that allow you to develop significantly accelerated CGI applications. If you develop Perl CGI scripts on Win32, then you may also wish to look at ActiveState’s PerlEx. Although we do not discuss PerlEx in this chapter, it provides many of the same benefits as mod_perl.

First, let’s try to understand why CGI applications are so slow. When a user requests a resource from a web server that turns out to be a CGI application, the server has to create another process to handle the request. And when you’re dealing with applications that use interpreted languages, like Perl, there is an additional delay incurred in firing up the interpreter, then parsing and compiling the application.

So, how can we possibly improve the performance of Perl CGI applications? We could ask Perl to interpret only the most commonly used parts of our application, and delay interpreting other pieces unless necessary. That certainly would speed up applications. Or, we could turn our application into a server ( daemon) that runs in the background and executes on demand. We would no longer have to worry about the overhead of firing up the interpreter and evaluating the code. Or, we could embed the Perl interpreter within ...