From d6ca23a75b3501e4fff40eb81bc802828faea07d Mon Sep 17 00:00:00 2001
From: Sam <sam@ubuntu.(none)>
Date: Fri, 8 Mar 2013 05:34:19 -0800
Subject: [PATCH] remove N+1 queries

---
 app/models/category.rb | 6 +++++-
 app/models/site.rb     | 2 +-
 lib/topic_query.rb     | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/app/models/category.rb b/app/models/category.rb
index c1643c68aa5..f55aaa786b4 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -1,5 +1,9 @@
 class Category < ActiveRecord::Base
   belongs_to :topic, dependent: :destroy
+  belongs_to :topic_only_relative_url, 
+    select: "id, title",
+    class_name: "Topic",
+    foreign_key: "topic_id"
   belongs_to :user
 
   has_many :topics
@@ -43,7 +47,7 @@ class Category < ActiveRecord::Base
   end
 
   def topic_url
-    topic.try(:relative_url)
+    topic_only_relative_url.try(:relative_url)
   end
 
   before_save do
diff --git a/app/models/site.rb b/app/models/site.rb
index 1d63ae46eb5..f4c4f9f3125 100644
--- a/app/models/site.rb
+++ b/app/models/site.rb
@@ -22,7 +22,7 @@ class Site
   end
 
   def categories
-    Category.popular
+    Category.popular.includes(:topic_only_relative_url)
   end
 
   def archetypes
diff --git a/lib/topic_query.rb b/lib/topic_query.rb
index f6a75dcaaf6..86fecc981ca 100644
--- a/lib/topic_query.rb
+++ b/lib/topic_query.rb
@@ -196,7 +196,7 @@ class TopicQuery
         end
       end
 
-      result = result.listable_topics.includes(:category)
+      result = result.listable_topics.includes(:category => :topic_only_relative_url)
       result = result.where('categories.name is null or categories.name <> ?', query_opts[:exclude_category]) if query_opts[:exclude_category]
       result = result.where('categories.name = ?', query_opts[:only_category]) if query_opts[:only_category]
       result = result.limit(page_size) unless query_opts[:limit] == false