"This document describes how to customize the session handlers in PHP4. We will provide examples of how to write a fully functional session handler that works with DBM files and one that works with a MySQL database."

"New to PHP4 was a set of native session handling functions which was badly missing from PHP3. By default, each session is stored as a separate file in your temporary directory (eg. /tmp in Unix). This may or may not be appropriate depending on your requirements. For example, if you have a bunch of web/PHP servers on different machines, you can't easily share sessions between them (well you could save the sessions on an NFS share but that would be slow). Another problem is that you potentially have thousands or even millions of session files cluttering up your file system (you run a big site right )."

"Fortunately for us, the developers of PHP4 were forward thinking enough (thanks!) to provide the ability for users like you and me to extend the session handling routines."

Complete Story.