Applications for the Web
The second approach to solving CGI's performance problems was to hand off the
management of the web application processes completely to a separate system. The
separate system would pre-fork and maintain a pool of processes running the web
application code. Like web server pre-forking, these could be reused for each client
connection. New protocols were developed to allow the web server to pass requests
to the external processes, the most notable being FastCGI and SCGI. In this situation,
our journey would be:
Again, how the request is transformed and presented to the web application depends
on the protocol used.
Although in practice this is somewhat more complex to configure, it has advantages
over embedding a copy of the application code in pre-forked web server processes.
Primarily, the web application process pool can be managed independently of the
web server process pool, allowing more efficient tuning of both.