OPTIMIZATION: Don't run 12 queries every 15 mins for the Top section.

Instead, run the daily queries once every hour, and the reset of the
queries once a day.

app/jobs/scheduled/periodical_updates.rb

@@ -18,9 +18,6 @@ module Jobs
       # Update the scores of posts
       ScoreCalculator.new.calculate(1.day.ago)
 
-      # Update the scores of topics
-      TopTopic.refresh!
-
       # Automatically close stuff that we missed
       Topic.auto_close
 

app/jobs/scheduled/top_refresh_older.rb

@@ -0,0 +1,9 @@
+module Jobs
+  class TopRefreshOlder < Jobs::Scheduled
+    every 1.day
+
+    def execute(args)
+      TopTopic.refresh_older!
+    end
+  end
+end

app/jobs/scheduled/top_refresh_today.rb

@@ -0,0 +1,9 @@
+module Jobs
+  class TopRefreshToday < Jobs::Scheduled
+    every 1.hour
+
+    def execute(args)
+      TopTopic.refresh_daily!
+    end
+  end
+end

app/models/top_topic.rb

@@ -10,20 +10,36 @@ class TopTopic < ActiveRecord::Base
     @sort_orders ||= [:posts, :views, :likes]
   end
 
-  def self.refresh!
+  # The top topics we want to refresh often
+  def self.refresh_daily!
     transaction do
-      # update the topics list
       remove_invisible_topics
       add_new_visible_topics
-      # update the denormalized data
-      TopTopic.periods.each do |period|
+
       TopTopic.sort_orders.each do |sort|
-          TopTopic.send("update_#{sort}_count_for", period)
+        TopTopic.send("update_#{sort}_count_for", :daily)
       end
-        # compute top score
-        TopTopic.compute_top_score_for(period)
+      TopTopic.compute_top_score_for(:daily)
     end
   end
+
+  # We don't have to refresh these as often
+  def self.refresh_older!
+    older = TopTopic.periods - [:daily]
+
+    transaction do
+      older.each do |period|
+        TopTopic.sort_orders.each do |sort|
+          TopTopic.send("update_#{sort}_count_for", :daily)
+        end
+        TopTopic.compute_top_score_for(:daily)
+      end
+    end
+  end
+
+  def self.refresh!
+    TopTopic.refresh_daily!
+    TopTopic.refresh_older!
   end
 
   def self.remove_invisible_topics