Back in 2001 when I created the PHP Accelerator it was a massive shock to Zend. There was APC and a few other opensource caches, but they were all 30% or so slower than Zend Cache. I’d been using PHP for only a few days when I realised that it was quite slow and that there had to be a way to speed it up, so I started looking at caching. I didn’t know about the other caches at the time, although when I did I realised that they were clearly missing a trick as their performance was poor in comparison to Zend.

Following a frantic 3 weeks of development, PHPA was usable and the first cache to match or run faster than Zend Cache, with the crucial trick being to execute code directly from SHM.

After releasing the PHP Accelerator for others to benefit, Zeev Suraski got in touch asking what the intentions were; he was clearly worried, and concerned that their monopoly on the PHP market was being threatened. As a gesture of good will I made a promise not to release the source, so it remained closed source but free and maintained for several years, and adopted by countless sites globally from hobby sites to large enterprises such as Yahoo.

After steering the APC developers in the right direction to improve their cache, and with other developers taking an interest in PHP internals, more caches appeared over time and there are several choices. EAccelerator, a fork of the dead mmcache project, APC, and the promising newcomer XCache are all worthy. EAccelerator in particular benefits from some good code optimisation strategies, helping to boost performance further.

I guess what I’m trying to say is a) don’t believe this’ll solve every problem and b) I’d be curious about how other solutions or more modern versions of the Zend stuff work out. Not curious enough to try them out, though, I’ve left PHP behind for the most part