Unable to add Impressionist model to Solr

[sahil290791]

As we have lots of users visiting the platform, impressions table will grow at a higher rate. This will cause problems later when I want to show a comparison between consecutive weeks/months.

So I thought of adding solr to it. To implement this I first created a model named impression under app/models/impression.rb folder.

class Impression < ActiveRecord::Base

       attr_accessible :user_id, :ip_address, :action_name, :controller_name, :impressionable_type, :impressionable_id, :view_name, :session_hash, :message, :request_hash, :referrer

	searchable :ignore_attribute_changes_of => [ :updated_at] do
	    text :message, :boost=> 2.0
	    text :referrer
	    text :ip_address
	    integer :user_id
	    time :created_at
	    time :updated_at       
	    string :message
	    string :view_name
	    string :ip_address
	    string :impressionable_type 
	    string :controller_name
	    string :action_name
	    string :session_hash
	    string :request_hash
	    integer :id
	    integer :impressionable_id   
	  end
end

Then I viewed few blogposts where impressionist was implemented and then did solr reindexing.

bundle exec rake sunspot:reindex[,Impression]
[###########################################################################################################] [4/4] [100.00%] [00:00] [00:00] [2.78/s]
# This did the reindexing.

Next I tried using solr to query Impression model.

search = Sunspot.search Impression do
      with(:impressionable_type).equal_to('Blogpost')
      with(:impressionable_id).equal_to(1)
    end.total
    puts "total results #{search || 0}"
search

The above code keeps throwing this error:

undefined method `field' for nil:NilClass
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/dsl/standard_query.rb:112:in `with'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/util.rb:241:in `__proxy_method__'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/util.rb:236:in `method_missing'
from (irb):8:in `block in irb_binding'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/util.rb:208:in `instance_eval'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/util.rb:208:in `instance_eval_with_context'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/util.rb:86:in `instance_eval_or_call'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/search/abstract_search.rb:202:in `build'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/session.rb:50:in `new_search'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/session.rb:58:in `search'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot/session_proxy/abstract_session_proxy.rb:11:in `search'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-queue-0.10.2/lib/sunspot/queue/session_proxy.rb:62:in `search'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/sunspot-2.1.0/lib/sunspot.rb:345:in `search'
	from (irb):8
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/railties-3.2.14/lib/rails/commands/console.rb:47:in `start'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/railties-3.2.14/lib/rails/commands/console.rb:8:in `start'
	from /home/xyz/.rvm/gems/ruby-2.1.0/gems/railties-3.2.14/lib/rails/commands.rb:41:in `<top (required)>'
	from script/rails:6:in `require'

Can anyone tell me how can I create a Impression model for using it with solr?