Rails Query optimization

Question

I have two modals whom they have association with each other. I need to optimize my code so I have eager loaded modal2 when I am loading modal1.

Now my problem here is I have a named_scope in my modal2 code which poses some condition on my result based on the column of modal2. When I am calling this named scope the app is again hitting the database which is reducing my app performance.

Code Format

Modal1

Class Modal1 < ActiveRecord::Base
...
    has_association :modal2 # some association which we can access through . operator
    named_scope :egr_load ,:include => [:modal2]
...
end

Modal2

Class Modal1 < ActiveRecord::Base
...
   named_scope :not_deleted, :conditions => ['deleted_at IS ?', nil] # some condition on its own colums
...
end

Code calling these classes

def method
    
    Modal1.egr_load.each{|ref2|
       ref2.modal2.not_deleted # Here this is again hitting the DB.
    }
end

Could any one please let me know how I can avoid this DB hitting second time when eagerly loaded object's named scope which had condition on its own column is called.

Thanks in advance

Answer 1

I voted to close as a duplicate of Rails 3 - Eager loading with conditions, but if the number of deleted records is not too large you might just:

Modal1.egr_load.each do |ref2|
  unless ref2.modal2.deleted_at.nil?
    ...
  end
end

Answer 2

I think that the eager loading here will have no effect since you are running a second query on the object that you have already eagerly loaded, and this will require Rails to query the database once again.

The solution is to append all these conditions to the main query before the each block, eg:

Modal1.egr_load.custom_condition_on_modal2.each do |ref2|
    ref2 # will already be chosen between the not deleted objects
end