mod_perl

mod_perl is an Apache HTTP Server module that embeds the Perl interpreter into the web server. This allows Perl code to be precompiled and kept in memory, leading to significant performance improvements for Perl-based web applications compared to using CGI (Common Gateway Interface). Instead of starting a new Perl interpreter for each request, mod_perl keeps one or more interpreters running within the Apache process, reducing overhead.

The primary benefit of mod_perl is faster execution of Perl scripts used in web development. This is achieved by eliminating the startup time of the Perl interpreter for each request and by allowing Perl code to persist between requests. This persistence enables more efficient database connections and other resource management techniques.

mod_perl allows developers to write Apache modules in Perl, providing direct access to the Apache API. This offers a high degree of flexibility and control over the server's behavior.

However, mod_perl also has drawbacks. It can increase the memory footprint of the Apache web server due to the resident Perl interpreters. It also requires careful coding practices to avoid memory leaks and other potential issues that can arise from long-running processes. Careful configuration is needed to ensure the stability of the web server. Additionally, deploying and managing mod_perl applications can be more complex than traditional CGI applications.