Merge pull request #202 from edx/perf/tracing-and-consistency

Add more tracing + code cleanup.

api/comment_threads.rb

 get "#{APIPREFIX}/threads" do # retrieve threads by course
-  
-  threads = Content.where({"_type" => "CommentThread", "course_id" => params["course_id"]})
+  threads = CommentThread.where({"course_id" => params["course_id"]})
   if params[:commentable_ids]
     threads = threads.in({"commentable_id" => params[:commentable_ids].split(",")})
   end

models/comment.rb

+require 'new_relic/agent/method_tracer'
 require_relative 'content'
 require_relative 'constants'
 
@@ -164,4 +165,7 @@ class Comment < Content
       self.sk = (self.parent_ids.dup << self.id).join("-")
     end
   end
+
+  include ::NewRelic::Agent::MethodTracer
+  add_method_tracer :to_hash
 end

models/comment_thread.rb

@@ -133,7 +133,6 @@ class CommentThread < Content
               "group_id" => group_id,
               "pinned" => pinned?,
               "comments_count" => comment_count)
-
   end
 
   def comment_thread_id
@@ -162,4 +161,7 @@ class CommentThread < Content
   def destroy_subscriptions
     subscriptions.delete_all
   end
+
+  include ::NewRelic::Agent::MethodTracer
+  add_method_tracer :to_hash
 end

presenters/thread_utils.rb

@@ -31,7 +31,7 @@ module ThreadUtils
             unread_comment_count = Comment.collection.find(
               :comment_thread_id => t._id,
               :author_id => {"$ne" => user.id},
-              :updated_at => {"$gte" => read_dates[thread_key]}
+              :updated_at => {"$gte" => read_dates[thread_key]},
               ).count
             read_states[thread_key] = [is_read, unread_comment_count]
           end