#365 Thread-Safety pro

I'm using Unicorn in production, and I have a (probably) dumb question. If I enable threadsafe, will this help (even if just slightly) the memory usage by not loading the Rack::Lock middleware?

You mentioned Rubinius/JRuby - how about an episode deploying to these platforms?

Thanks for the video, I found it very useful. You mentioned at the end that Rails' controllers are limited by database Pool connection size, even when you're not using a database connection in your action. That kind of floored me, I've written tons of controller actions that never talk to ActiveRecord, never realizing that AR could still be a bottleneck.

Very useful screencast and I was interested in this when T-Love originally posted.

Anyone know if attr_accessible is considered a class variable (i.e., requiring a mutex lock if I enable Threadsafe!)?

Example --

I have a Post model that dynamically sets attr_accessible from the Posts controller based on a user's permission.

The controller action first looks up the user and then looks up the user's permissions (for example, an admin user would have all fields accessible.) Would I wrap this in a mutex? Any idea how to even test concurrent action calls with more involved than just hitting a controller action with a generic get (i.e., a put or post with data...)?

I have one question about the class variable that is preceded by @@, I know that the Web is stateless and everytime a request comes to a server it is as if it's the first time they meet each other. since I don't see any database in the example, the @@counter must be incremented 5 times to get to the number 5, but if it loses its state in each request, how does it ever get up to 5? does that repeat 5 command tell the connection to stay alive for another request? or is that & at the end of the curl command doing this? I hope I am making sense here...

Thanks for saving me a few hours of research to understand the significance of the change.

I've been playing with this setting and have run into a bit of a gotcha.

tl;dr - models don't load in rake tasks/migrations - do this:
config.threadsafe! unless $rails_rake_task or explicitly require the model.

The dependency_loading = false setting in the threadsafe! method means that you won't have access to your models in migrations or rake tasks (ie. db:seed).

It's described here this old rails issue and discussed in this article.

Cool, thanks very much. I will try it later.

Is repeat a ZSH command? Is that available for bash? I can't figure out where you got it.

Can someone point me in the right direction?

Are Time.zone or I18n.locale thread safe? They seem like class variables, but are used in most Rails apps.

Hi guys,
I see that paper_trail gem uses the Thread.current to pass current_user to model. Is it safe to use it when we use server like puma?

How did you get this 'repeat' command?

Hi, I got this question. What if in the bar action, instead of saying

def bar
  count = @@count
  count += 1
  @@count = count
  render text: "#{@@count}"
end

The developer can just type as:

def bar
  @@count += 1
  render text: "#{@@count}"
end

Is my last code considered to be thread-safe?

In Java, we may need to put a keyword 'volatile' on variables of an object which is shared across different threads. What about Ruby in our case ??

Thanks if you could let me know

If you're looking for a non-blocking, real time Rails solution, check out Entangled: https://github.com/dchacke/entangled

Thanks for this