Why do people say that Ruby is slow?
I like Ruby on Rails and I use it for all my web development projects. A few years ago there was a lot of talk about Rails being a memory hog and about how it didn't scale very well but these suggestions were put to bed by Gregg Pollack here.
Lately though, I've been hearing people saying that Ruby itself is slow.
- Why is Ruby considered slow?
I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages?
What are your options as a Ruby programmer if you want to deal with this "slowness"?
Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense?
The questions are subjective, and I realise that architectural setup (EC2 vs standalone servers etc) makes a big difference but I'd like to hear what people think about Ruby being slow.
Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?
Answer
Why is Ruby considered slow?
Because if you run typical benchmarks between Ruby and other languages, Ruby loses.
I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages?
Ruby probably wouldn't serve you well in writing a real-time digital signal processing application, or any kind of real-time control system. Ruby (with today's VMs) would probably choke on a resource-constrained computer such as smartphones.
Remember that a lot of the processing on your web applications is actually done by software developed in C. e.g. Apache, Thin, Nginx, SQLite, MySQL, PostgreSQL, many parsing libraries, RMagick, TCP/IP, etc are C programs used by Ruby. Ruby provides the glue and the business logic.
What are your options as a Ruby programmer if you want to deal with this "slowness"?
Switch to a faster language. But that carries a cost. It is a cost that may be worth it. But for most web applications, language choice is not a relevant factor because there is just not enough traffic justify using a faster language that costs much more to develop for.
Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense?
Other folks have answered this - JRuby, IronRuby, REE will make the Ruby part of your application run faster on platforms that can afford the VMs. And since it is often not Ruby that causes slowness, but your computer system architecture and application architecture, you can do stuff like database replication, multiple application servers, loadbalancing with reverse proxies, HTTP caching, memcache, Ajax, client-side caching, etc. None of this stuff is Ruby.
Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?
Most folks are waiting for Ruby 1.9.1. I myself am waiting for Rails 3.1 on Ruby 1.9.1 on JRuby.
Finally, please remember that a lot of developers choose Ruby because it makes programming a more joyful experience compared to other languages, and because Ruby with Rails enables skilled web developers to develop applications very quickly.