Comments on: How to save 100m of RAM per mongrel

By: Ara

Ara — Sat, 08 Nov 2008 22:20:00 +0000

Wait. Why do we need to workaround this? Why is Rails creating 100mb of extraneous objects *on startup*? Surely there is a problem with the default behavior in that case.

By: Neeraj

Neeraj — Sat, 08 Nov 2008 22:20:00 +0000

This is really really interesting. I will give the patch a try.

By: Lourens Naude

Lourens Naude — Sat, 08 Nov 2008 22:20:00 +0000

Aaron,

Routes double total RSS use for large applications.We had similar downsizing in our environment.

http://github.com/methodmissing/routing_with_optional_formats/tree/master

There’s yet another optimization pattern – only mapping routes for actions that exist iow. if a controller only responds to 1 REST action, only map that, not all 7.

http://gist.github.com/23253

The current Rails initializer sequence complicates clean optimizations and to get the Gist snippet to fire, one has to do stick it in config/initializers/ and

RouteFilter.prune! if Rails.env.production?

in environment.rb, after the config block.This however still doesn’t save on memory as downsizing an Enumerable doesn’t yield memory back to the OS, but yields noticeable differences in recognition overhead.

The Anonymous module that installs named routes in ActionController, ActionView etc. is also a candidate for similar optimization ( undef_method ?, but see below ).

It would be most excellent if Rails::Initializer could be tweaked to setup routing AFTER preloading application klasses ( current default for Prod. env ) to allow for a more granular routing table, but this may break existing plugins, assumptions etc.

Getting this right has huge ramifications for the Rails hosting space.

Thoughts ?

- Lourens

By: AkitaOnRails

AkitaOnRails — Sat, 08 Nov 2008 22:20:00 +0000

@Lourens, feels like a nice good addition for Rails Core. Have you tried opening up a new Ticket with your implementation so Routes become more flexible and save more memory?

By: Hongli Lai

Hongli Lai — Sat, 08 Nov 2008 22:20:00 +0000

Interesting. Have you also experimented with Phusion Passenger + Ruby Enterprise Edition? If you use those two together, then the memory occupied by the compiled routes will be shared between all Rails processes, which should also reduce your total memory usage significantly.

By: Jeff

Jeff — Sat, 08 Nov 2008 22:20:00 +0000

I’m very interested in trying this, but I can’t seem to get it to work properly. What version of Rails are you using? Where are you placing the monkey-patch?

Thanks
-jeff

By: Pratik

Pratik — Sat, 08 Nov 2008 22:20:00 +0000

Rails lighthouse already has a patch for this at http://rails.lighthouseapp.com/projects/8994/tickets/1215-add-actions-and-formatted-options-to-mapresources

I imagine that should solve this problem.

By: Tom

Tom — Sat, 08 Nov 2008 22:20:00 +0000

Yes, please see my patch on Lighthouse, and add your voice there if you’d like to see it included in Rails. Your comments and benchmarks would really help convince the core team.

Introspecting the controllers feels like a bit too much magic for me — loading order problems aside, I’m a fan of documenting the desired routes explicitly in routes.rb as you can see from the ticket — but anything that reduces the astonishing memory overhead of the default routing is great news!

By: Anil

Anil — Sat, 08 Nov 2008 22:20:00 +0000

It’s really nice. I will give it a try.

By: Jens

Jens — Sat, 08 Nov 2008 22:20:00 +0000

Sounds cool, but I don’t really get it. Which version of rails did you monkey patch? All versions I checked (originally I wanted to apply this to one of our apps using rails 2.0.5) didn’t had the methods you changed but had a lot of duplicated code in actionpack/lib/action_controller/resources.rb in the form:

show_action_options = action_options_for("show", resource)
map.named_route("#{resource.name_prefix}#{resource.singular}", resource.member_path, show_action_options)
map.named_route("formatted_#{resource.name_prefix}#{resource.singular}", "#{resource.member_path}.:format", show_action_options)

update_action_options = action_options_for("update", resource)
map.connect(resource.member_path, update_action_options)
map.connect("#{resource.member_path}.:format", update_action_options)

destroy_action_options = action_options_for("destroy", resource)
map.connect(resource.member_path, destroy_action_options)
map.connect("#{resource.member_path}.:format", destroy_action_options)

I tried to comment out the .format which worked ok, but that’s of course much worse than monkey patching and only worth the experiment.