How to diagnose slow rails / rake / rspec tasks

Question

I always have a significant delay (c.10 seconds) when running tasks like:

• rails server
• rake assets:precompile
• rspec spec

The delay is at the point before it says:

    Connecting to database specified by database.yml

I've found several articles identifying 10 or more different parameters that can be tuned to speed up rake and / or rspec runs. But I'm reluctant to start fiddling around with 10 different parameters without a better understanding of what's causing it.

Is there way to diagnose what's causing that delay? Like something more verbose?

Supplementary info: Ubuntu 14 Ruby 1.9.3 Rails 3.2

Answer 1

Thanks to @MaxWilliams for the link to this post How do I debug a slow rails app boot time?

I started using Mark Ellul's Bumbler - http://github.com/mark-ellul/Bumbler

It gave me exactly what I wanted - an insight into what's going in the background and which gems are taking the time. Of course I still need to speed up the slow ones (fog and authlogic seem to be two of the main culprits). But that's at different question.