Since I follow most of the mailing lists for Symfony 2, I have come across Silex a little while ago. However, something new I took from this article was the appserver-in-php project https://github.com/indeyets/appserver-in-php
The blurb on the git project has "The main idea is, that your app, if built for this protocol, will be able to preload resources, preconnect to databases and response to requests really fast.", which seems like it's taking a persistent approach to running PHP apps. How does this deal with the memory leaks etc?
Can anybody knowledgeable weigh in on this with a little detail about what it is, how stable it is, who's using it, how it stacks up to using PHP-FPM in a spawner pool w/ nginx etc... ?
I'm the author of the original post. We use AiP quite a bit in production.
Indeed, memory leaks are a potential issue with persistent PHP. Garbage collection in 5.3 helps a bit, but in general AiP exposes such issues more readily than regular mod_php setups. This doesn't mean memory leaks in your code wouldn't be an issue anyway, it just means you'll notice them a lot more quickly.
AiP workers die when PHP's memory_limit is exceeeded, and AiP will then restart them.
Thank you for your reply. I will have a play with it if I find some free time. It's not the memory leaks in _my_ code I'm so worried about, it's the ones in other people's code :-) e.g. Doctrine used to leak like a sieve and no amount of free()s and unset()s cleared the ORM objects up under some circumstances. Long-running Symfony tasks were a great way to illustrate that. It seems like a sensible approach to auto-restart the processes once memory_limit is exceeded.
While I'm relieved to see that, I wouldn't expect anything less from a trivial example such as this. I wonder if the same would be true if you hit a database, hydrated a one-to-many related series of objects from multiple tables using an ORM, modified some of them and save them etc.
However, I don't mean to harp on about the memory leaks; It's just that it seems to have been an assumed wisdom in my long association with PHP that you're going to need to restart PHP processes eventually. Perhaps the GC in 5.3 alleviates some of these concerns (including detection of circular references), as does the maturing of the code base and the commonly used libraries over the years.
The fact that you are using AiP happily in production already means that there is both a niche and a successful way to implement this so I'm glad to see new approaches like this emerging.
But 5.3 solved all of the issues. The only leaks happening these days come from "unofficial" extensions, which introduce errors on C-level. PHP code _never_ results in memory leaks these days, as far as I know.