em-synchrony

Well, ruby was able to be concurrent for a while now. It has lightweight cooperative threads, it has reactor loops. The problem was/is/will be - lack of gems that support either of them. EventMachine was a nightmare to work on and to work with, but with fibers it and some wrappers you could write some neat code. Most library were making a lot of bad assumptions - "there is a GIL and i'm running on a full thread and also wtf are threads in general, never heard of it?" Almost no one in ruby world thought about writing a better code to make application faster, it was always about either finding a better gem or adding more application servers. Here is the closest ruby has been towards concurrency https://github.com/igrigorik/em-synchrony guess why it never took off. Ruby 3.0 is a first step towards having libraries being aware that they are i

The em-synchrony project (https://github.com/igrigorik/em-synchrony) has patched versions of the mysql gem and they say they can run most of the rails stack. They use a fiber model to un-event the program flow a bit. Ilya is brilliant really. Still, I would be a little leary of betting LinkedIn on a bunch of monkey-patched client code. The challenge in porting to EM is that so many Ruby network clients will block. With Node.js that is impossible. I think though for a rewrite it wouldn't matter, you'd use the right libraries and design your app around the framework just like they had to do switching to Node.

Thank you for the feedback! Typos: Yeah, I'm German. Could you just point out some of the errors (2-3), that would help me to look for them harder next time :) Lack of detail towards the end: The thesis was written after most of the project was done and I wanted to give people new to the field an introduction to the tools I used and the problems I encountered. All of this was an actual internship project and the ability to use it as my thesis was just a nice "addon". That's probably why you (rightfully) noticed that some of the competitive solutions (e.g. graph databases) might have not gotten the level of detail and research they deserved. It was a balance between delivering a working product and putting the thesis on a theoretically sound basis while moving to another country :) In general, I'd re-implement it more or less the same way.

Haha, I got my own domain name wrong! Clearly it's been a long day... Link: http://ajax-gist.com/ In the end I built what was essentially a proof-of-concept asynchronous Rails 3 application. The libraries I used under the hood to get everything async were: * Rack/Fiber-Pool: http://github.com/mperham/rack-fiber_pool * EM Synchrony: http://github.com/igrigorik/em-synchrony * Eventmachine: http://rubyeventmachine.com/ Using Rails for what is essentially a thin proxy is overkill, and I could have gotten better performance with Node or by writing a Rack application directly. But I wanted to take the opportunity to get a handle on what would be involved with doing this in Rails, as not too many people have done it before that I am aware of (and at the time no-one had done it with Rails 3).

Great stuff. Just for sake of completeness, you can basically copy-paste that code into Ruby as well via em-websocket: http://github.com/igrigorik/em-websocket Also, to avoid some of the callback muck that a few have brought up: http://github.com/igrigorik/em-synchrony (same idea, closures + coroutines to abstract the callbacks).