Alternative PHP Cache

This is a list of PHP accelerators.

Alternative PHP Cache is a free and open (PHP license) framework that caches the output of the PHP bytecode compiler in shared memory, thus reducing parsing and disk I/O overhead for later requests; and a shared memory cache for user data. For an application consisting of a large source code base such as Drupal, a 3x increase in page generation speed is possible as a result.

It has been used at Facebook and has a mature codebase thanks to numerous contributors, including Facebook itself.

APC was originally scheduled for inclusion into the PHP core no later than PHP 6. While multiple accelerator projects were considered desirable, the focus has since moved to Optimizer Plus, and, later, Zend Opcache that is included in the core distribution as of PHP 5.5. Since March 2013, a beta version of APCu (APC User Cache) is available, in which all opcode caching abilities have been removed to support user caches in shared memory using the familiar APC API.

eAccelerator was born in December 2004 as a fork of the Turck MMCache project. Turck MMCache was created by Dmitry Stogov and much of the eAccelerator code is still based on his work. eAccelerator also contained a PHP encoder and loader, but the development staff discontinued the encoder and removed this feature after December 2006.

Launched in 2001, ionCube PHP Accelerator (PHPA) was the first freely available PHP accelerator to compete with the commercial Zend Cache product. Created before ionCube Ltd. was founded and at a time when the performance of PHP was regarded as lackluster when compared to other popular web programming languages, PHPA showed that PHP can compete with other languages performance-wise. Although the author of PHPA chose to keep the project closed source in response to early concerns raised by Zeev Suraski of Zend Technologies about the effect that an open source rival might have on their commercial alternative, the availability of PHPA on a wide variety of platforms led to its extensive adoption worldwide from small sites to Yahoo!. It also inspired the redevelopment of APC to use the shared memory execution techniques that PHPA and Zend Cache had adopted instead of deserialization on each request that incurred performance penalties.

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