On the IBuildings techPortal today there's a new tutorial from Vito Chin that wants to help you understand what APC (the Alternative PHP Cache) is all about and get you on the road to using it in your application.

APC is a performance-enhancing extension. It should not be confused with a magic pill, although having it around does provide a positive impact on performance! If configured incorrectly, APC can cause unexpected behaviour, however when implemented optimally APC can be a useful weapon in your arsenal. In this post we will examine APC's capabilities and it’s application both as an opcode cache and in its less common usage as a data cache.

He starts off by comparing/contrasting it with memcache, nothing that APC is more targeted towards PHP and is more useful for caching smaller bits of information (like objects). He talks about the importance of using APC for an application, what the system really caches and some of the limitations that come with it. There's code snippets to help illustrate some of the points and the article is rounded out with a look at file caching, the time-to-live setting and how you can monitor your cache's health.