Zend has posted a new case study today concerning Orase (a real-time search engine) and their migration to PHP.

Due to its use of real-time search technology, Orase needed to be written in a powerful and extensible language. At the beginning of the Orase project, PHP 4 was the solution for almost every problem I had, and so PHP became the most-used language in the application. Roughly 92% of the code base is written in PHP.

[...] As I mentioned at the beginning of this article, Orase uses a new search technology; it searches the Web in real time. To understand the problems unique to Orase, it is first necessary to know how a search query is handled by the application.

Because of this feature, Orase needs to spawn multiple processes to load web pages (previously via an external Python function, now with the CURL library). They go on, examining how they migrated to PHP 5, how it has benefited them, and how much it contributed to the happiness of the developers...