Since 开发者_StackOverflow"upgrading" to Rails 3.1 my app is really slow in development mode

(> 30 per request)

I have a lot of images and it seems most of this time-delay is the asset pipeline processing each GET request for each image.

Don't have this problem in Staging or Production mode as the assets are cached etc.

Is there something I haven't been told or is this how we're expected to work now?

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Requests can be slow if you have gems or portions of your app that load code at the start of each request - or that merely reference portions of your app, causing much of it to be loaded. For most of these, the autoloader is the prime cause of request delay.

The rails auto-reloader deletes any autoloadable classes/modules/etc at the start of each request, and can cause significant delays at the beginning of each request as Rails reloads all the source files it needs.

You might want to try playing with https://github.com/wavii/rails-dev-tweaks, which gives you granular control over which requests cause the auto-reloader to kick in. This really isn't a fix of the root cause (something is doing extra work at the start of every request that it probably doesn't need to be doing) - but it certainly mitigates most such issues.

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In the meantime:

cp -R app/assets/images public/assets

really helps

remember to add public/assets/* to .gitignore

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If your app is slow it is because of your app or one of the gems that you use. I had similar issue and it looks like Mongoid was the case more you can read here:

http://martinciu.com/2011/06/rails-3-1-and-slow-asset-pipeline.html

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You can use a rake task:

rake assets:precompile RAILS_ENV=development RAILS_ASSETS_NONDIGEST=true

And as it was mentioned above, don't forget to include public/assets/* to .gitignore