You may or may not be aware, but PHP has two separate module implementations wrapping the memcached (as in memcache daemon) server.
The memcache module utilizes this daemon directly, whereas the memcached module wraps the libMemcached client library and contains some added bonuses.
Both modules have built-in support for session handling, which can be specified in your php.ini file using session.save_handler = memcache[d].
You may see speed improvements if you decide to go with the full-blown install of the memcached module. The primary reason for this would be it’s use of the igbinary PHP extension; a drop in replacement for PHP’s serializer. There is currently a 2.0 beta (RC1) with a number of goodies.
I don’t enjoy re-creating the wheel, so instead I’ve compiled a series of pages I’ve found helpful in the past regarding these two modules for you to make your own decisions.
Memcache/Memcached References
I have compiled a series of the most useful links for your reading pleasure. You’ll be an expert in no time.
- PHP Memcached Client Comparison
A tabular comparison of the two memcache modules created by Brian Moon; limited in details. - PHP and Memcached: The state of things
Brian Moon walks through existing issues with the memcache modules. - New PECL extension memcached released
The initial blog post of digg referencing the newly available memcached module and it’s features. - Using Memcache vs Memcached with PHP
Informative answers regarding the differences of the two clients. - memcache vs memcached?
References the naming discrepancies of the two modules. - PECL Memcache
The official PECL page of memcache; includes release dates, bug reports, and changelogs. - PECL Memcached
The official PECL page of memcached; includes release dates, bug reports, and changelogs. - php-memcached github repository
The most up to date code available for the memcached php module. - PHP: Memcache – Manual
The official PHP documentation of memcache. - PHP: Memcached – Manual
The official PHP documentation of memcached. - Igbinary
A drop in replacement for the standard PHP serializer. Instead of time and space consuming textual representation, igbinary stores PHP data structures in a compact binary form. Savings are significant when using memcached or similar memory based storages for serialized data.
Unless you are a high-security site (more than just e-commerce) you should be crowd-sourcing your session management to the users that wish to use your service. Almost every good framework now comes with an encryption class for using encrypted cookies instead of wasting your RAM holding the same information in memcached.