major SQL optimization. how did we get away with so few indexes?!

db/migrate/20120321214802_index_associations.rb

@@ -0,0 +1,41 @@
+class IndexAssociations < ActiveRecord::Migration
+  def self.up
+    add_index :closet_hangers, :item_id
+    add_index :closet_hangers, :list_id
+    add_index :closet_hangers, :user_id
+    
+    add_index :closet_lists, :user_id
+    
+    add_index :contributions, [:contributed_id, :contributed_type]
+    add_index :contributions, :user_id
+    
+    add_index :item_outfit_relationships, :item_id
+    add_index :item_outfit_relationships, :outfit_id
+    
+    add_index :outfits, :pet_state_id
+    add_index :outfits, :user_id
+    
+    remove_index :parents_swf_assets, :name => "parent_swf_assets_parent_id"
+    add_index :parents_swf_assets, [:parent_id, :parent_type]
+  end
+
+  def self.down
+    remove_index :closet_hangers, :item_id
+    remove_index :closet_hangers, :list_id
+    remove_index :closet_hangers, :user_id
+    
+    remove_index :closet_lists, :user_id
+    
+    remove_index :contributions, [:contributed_id, :contributed_type]
+    remove_index :contributions, :user_id
+    
+    remove_index :item_outfit_relationships, :item_id
+    remove_index :item_outfit_relationships, :outfit_id
+    
+    remove_index :outfits, :pet_state_id
+    remove_index :outfits, :user_id
+    
+    add_index "parents_swf_assets", :parent_id, :name => "parent_swf_assets_parent_id"
+    remove_index :parents_swf_assets, [:parent_id, :parent_type]
+  end
+end

db/migrate/20120321222001_index_closet_hanger_query.rb

@@ -0,0 +1,22 @@
+class IndexClosetHangerQuery < ActiveRecord::Migration
+  def self.up
+    # SELECT COUNT(DISTINCT `closet_hangers`.`id`) FROM `closet_hangers` INNER
+    # JOIN `users` ON `users`.`id` = `closet_hangers`.`user_id` LEFT OUTER JOIN
+    # `closet_lists` ON `closet_lists`.`id` = `closet_hangers`.`list_id` WHERE
+    # `closet_hangers`.`owned` = XXX AND (`closet_hangers`.item_id = XXX) AND
+    # ((`closet_hangers`.`list_id` IS NULL AND
+    # `users`.`owned_closet_hangers_visibility` >= XXX OR
+    # `closet_lists`.`visibility` >= XXX));
+    
+    # It's not a huge improvement over the association index, but it's nice to
+    # be able to scan fewer rows for so little penalty, right?
+    
+    remove_index :closet_hangers, :item_id
+    add_index :closet_hangers, [:item_id, :owned]
+  end
+
+  def self.down
+    remove_index :closet_hangers, [:item_id, :owned]
+    add_index :closet_hangers, :item_id
+  end
+end

db/migrate/20120321231507_index_closet_hanger_query2.rb

@@ -0,0 +1,20 @@
+class IndexClosetHangerQuery2 < ActiveRecord::Migration
+  def self.up
+    # SELECT `objects`.* FROM `objects`
+    # INNER JOIN `item_outfit_relationships` ON
+    #   `objects`.id = `item_outfit_relationships`.item_id
+    # WHERE ((`item_outfit_relationships`.outfit_id = 138510) AND
+    #   ((`item_outfit_relationships`.`is_worn` = 1)));
+    
+    # Small optimization, but an optimization nonetheless!
+    # Note that MySQL indexes can be reused for left-subsets, by which I mean
+    # this index can also act as just an index for outfit_id. Neat, eh?
+    remove_index :item_outfit_relationships, :outfit_id
+    add_index :item_outfit_relationships, [:outfit_id, :is_worn]
+  end
+
+  def self.down
+    remove_index :item_outfit_relationships, [:outfit_id, :is_worn]
+    add_index :item_outfit_relationships, :outfit_id
+  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 => 20120112204234) do
+ActiveRecord::Schema.define(:version => 20120321231507) do
 
   create_table "auth_servers", :force => true do |t|
     t.string "short_name", :limit => 10,       :null => false
@@ -30,6 +30,10 @@ ActiveRecord::Schema.define(:version => 20120112204234) do
     t.integer  "list_id"
   end
 
+  add_index "closet_hangers", ["item_id", "owned"], :name => "index_closet_hangers_on_item_id_and_owned"
+  add_index "closet_hangers", ["list_id"], :name => "index_closet_hangers_on_list_id"
+  add_index "closet_hangers", ["user_id"], :name => "index_closet_hangers_on_user_id"
+
   create_table "closet_lists", :force => true do |t|
     t.string   "name"
     t.text     "description"
@@ -40,6 +44,8 @@ ActiveRecord::Schema.define(:version => 20120112204234) do
     t.integer  "visibility",    :default => 1, :null => false
   end
 
+  add_index "closet_lists", ["user_id"], :name => "index_closet_lists_on_user_id"
+
   create_table "colors", :force => true do |t|
     t.string  "name"
     t.boolean "basic", :default => false, :null => false
@@ -52,6 +58,9 @@ ActiveRecord::Schema.define(:version => 20120112204234) do
     t.datetime "created_at",                    :null => false
   end
 
+  add_index "contributions", ["contributed_id", "contributed_type"], :name => "index_contributions_on_contributed_id_and_contributed_type"
+  add_index "contributions", ["user_id"], :name => "index_contributions_on_user_id"
+
   create_table "forums", :force => true do |t|
     t.string   "name"
     t.text     "description"
@@ -68,6 +77,9 @@ ActiveRecord::Schema.define(:version => 20120112204234) do
     t.datetime "updated_at"
   end
 
+  add_index "item_outfit_relationships", ["item_id"], :name => "index_item_outfit_relationships_on_item_id"
+  add_index "item_outfit_relationships", ["outfit_id", "is_worn"], :name => "index_item_outfit_relationships_on_outfit_id_and_is_worn"
+
   create_table "login_cookies", :force => true do |t|
     t.integer "user_id", :null => false
     t.integer "series",  :null => false
@@ -105,16 +117,20 @@ ActiveRecord::Schema.define(:version => 20120112204234) do
     t.datetime "updated_at"
     t.string   "name"
     t.boolean  "starred",      :default => false, :null => false
+    t.string   "image"
   end
 
+  add_index "outfits", ["pet_state_id"], :name => "index_outfits_on_pet_state_id"
+  add_index "outfits", ["user_id"], :name => "index_outfits_on_user_id"
+
   create_table "parents_swf_assets", :force => true do |t|
     t.integer "parent_id",    :limit => 3, :null => false
     t.integer "swf_asset_id", :limit => 3, :null => false
     t.string  "parent_type",  :limit => 8, :null => false
   end
 
+  add_index "parents_swf_assets", ["parent_id", "parent_type"], :name => "index_parents_swf_assets_on_parent_id_and_parent_type"
   add_index "parents_swf_assets", ["parent_id", "swf_asset_id"], :name => "unique_parents_swf_assets", :unique => true
-  add_index "parents_swf_assets", ["parent_id"], :name => "parent_swf_assets_parent_id"
   add_index "parents_swf_assets", ["swf_asset_id"], :name => "parents_swf_assets_swf_asset_id"
 
   create_table "pet_loads", :force => true do |t|