Prompted by some discussion on rails-talk last week,  I worked up a
patch to add an option to ActiveRecord::Base#find which allows
associations to be :included for purposes of the where clause, but
defers instantiating the included association objects.

The use case is where there are a large number of association rows
returned by the query, the vast majority will not be used since they
are only being used to select a small set of root objects.

Here's the ticket with the patch:
http://dev.rubyonrails.org/ticket/9923

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/