add proper index to comments

db/migrate/20111018010003_add_back_indexes.rb

+class AddBackIndexes < ActiveRecord::Migration
+  def self.up
+    # reduce index size
+    change_column :comments, :commentable_type, :string, :default => "Post", :null => false, :length => 60
+    change_column :share_visibilities, :shareable_type, :string, :default => "Post", :null => false, :length => 60
+
+    add_index :photos, :status_message_guid
+    add_index :comments, [:commentable_id, :commentable_type]
+  end
+
+  def self.down
+    remove_index :comments, :column => [:commentable_id, :commentable_type]
+    remove_index :photos, :column => :status_message_guid
+
+    change_column :share_visibilities, :shareable_type
+    change_column :comments, :commentable_type
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20111012215141) do
+ActiveRecord::Schema.define(:version => 20111018010003) do
 
   create_table "aspect_memberships", :force => true do |t|
     t.integer  "aspect_id",  :null => false
@@ -62,6 +62,7 @@ ActiveRecord::Schema.define(:version => 20111012215141) do
   end
 
   add_index "comments", ["author_id"], :name => "index_comments_on_person_id"
+  add_index "comments", ["commentable_id", "commentable_type"], :name => "index_comments_on_commentable_id_and_commentable_type"
   add_index "comments", ["guid"], :name => "index_comments_on_guid", :unique => true
 
   create_table "contacts", :force => true do |t|
@@ -262,6 +263,8 @@ ActiveRecord::Schema.define(:version => 20111012215141) do
     t.integer  "comments_count"
   end
 
+  add_index "photos", ["status_message_guid"], :name => "index_photos_on_status_message_guid"
+
   create_table "pods", :force => true do |t|
     t.string   "host"
     t.boolean  "ssl"