The SitePoint PHP blog has posted an introductory tutorial showing you how to use Gearman in PHP to handle multitasking outside of the normal script execution. Gearman is an external job server that lets you schedule scripts and tasks for execution.
How many times have you developed a web application that had some functionality which would benefit from running an external program or even forking a separate process? This is not something you generally like to do from your web app because you want to make it run as fast and efficient as possible, while keeping the site functional for end users. So how do we get a fast but full-featured application that can process more than the average app we're used to?
They start by introducing you to Gearman - the server side - and how it works to handle a large amount of jobs quickly (50 thousand per second according to the article). They give the example of resizing images uploaded by users to illustrate. Next up is the installation - first Gearman then on to the PHP side, installing the PECL extension and adding it to the php.ini configuration. An example script is also provided showing how to create a new connection to Gearman and configure the callbacks for handling status changes. They also include adding two kinds of tasks - a normal one and a low priority one.