Improving Query/View Load-Time [Ruby on Rails] - ruby-on-rails

Question

I'm experiencing some pretty slow load times with one of the pages of my Rails app. I have made some headway in my attempts to improve performance, but not as much as I had hoped. I'm wondering if I'm doing something silly to cause myself this grief or if anyone could offer me advice to better optimize my models/migrations/queries/views. I'm running Rails 3.1 and using PostgreSQL. This is what I've tried so far:
added includes(:items => :category) to the controller's query, as an attempt to fetch all the ItemCategories in advance, rather than running additional queries when outfits_helper requires them.
rendering partials as collections, rather than iterating through arrays/relations manually
added indexes to tables that are being accessed by the problematic controller action / view
outfits table: indexes for user_id and category_id
items table: indexes for user_id and category_id
outfit_items table: indexes for item_id, outfit_id, and [outfit_id, item_id]
Below are the relevant parts of my code:
Controller
# outfits_controller.rb
NUM_OUTFITS_PER_PAGE = 8
def other_users_outfits
# using Kaminari for pagination
#outfits = Outfit.does_not_belong_to_user(current_user).in_category_with_id(category_id).includes(:items => :category).page(params[:page]).per(NUM_OUTFITS_PER_PAGE)
end
Models
# outfit.rb
has_many :items, :through => :outfit_items
belongs_to :category, :class_name => 'OutfitCategory'
scope :does_not_belong_to_user, proc {|user| where('user_id != ?', user.id) }
scope :in_category_with_id, proc {|cat_id|
if cat_id.blank?
scoped
else
where(:category_id => cat_id)
end
}
.
# outfit_item.rb
belongs_to :item
belongs_to :outfit
.
# item.rb
has_many :outfit_items
has_many :outfits, :through => :outfit_items
belongs_to :category, :class_name => 'ItemCategory'
.
# item_category.rb
has_many :items, :foreign_key => 'category_id'
.
outfit_category.rb
has_many :outfits, :foreign_key => 'outfit_id'
Migrations
# create_outfits.rb
def self.up
create_table :outfits do |t|
t.column :category_id, :integer
t.column :user_id, :integer
t.timestamps
end
add_index :outfits, :category_id
add_index :outfits, :user_id
end
.
# create_outfit_items.rb
def self.up
create_table :outfit_items, :id => false do |t|
t.column :item_id, :integer
t.column :outfit_id, :integer
t.timestamps
end
add_index :outfit_items, :item_id
add_index :outfit_items, :outfit_id
add_index :outfit_items, [:outfit_id, :item_id]
end
.
# create_items.rb
def self.up
create_table :items do |t|
t.column :category_id, :integer
t.column :user_id, :integer
t.timestamps
end
add_index :items, :category_id
add_index :items, :user_id
end
.
# create_item_categories.rb
def self.up
create_table :item_categories do |t|
t.column :name, :string
t.column :category_type, :string
t.timestamps
end
end
.
# create_outfit_categories.rb
def self.up
create_table :outfit_categories do |t|
t.column :name, :string, :limit => 100, :null => false
t.timestamps
end
end
Views
# other_users_outfits.html.haml
= render :partial => 'other_users_outfit', :collection => outfits, :as => :outfit
.
# _other_users_outfit.html.haml
.outfit
.primary-items
= render :partial => 'other_users_outfit_primary_item', :collection => primary_outfit_items_top_to_bottom(outfit), :as => :item
.secondary-items
= render :partial => 'other_users_outfit_secondary_item', :collection => secondary_outfit_items(outfit), :as => :item
.
# _other_users_outfit_primary_item.html.haml
= image_tag item.image_url(:outfit_item), :class => 'primary-outfit-item'
.
# _other_users_outfit_secondary_item.html.haml
= image_tag item.image_url(:baby_thumb), :class => 'secondary-outfit-item'
Helper
# outfits_helper.rb
def primary_outfit_items_top_to_bottom(outfit)
primary_items = []
primary_items.push(outfit_item_in_category(outfit, 'Tops'))
primary_items.push(outfit_item_in_category(outfit, 'Full-lengths'))
primary_items.push(outfit_item_in_category(outfit, 'Bottoms'))
primary_items.push(outfit_item_in_category(outfit, 'Footwear'))
primary_items.compact
end
def secondary_outfit_items(outfit)
outfit.items.select{|item| item.category.category_type == 'secondary' }
end
def outfit_item_in_category(outfit, cat_name)
outfit.items.select{|item| item.category.name == cat_name }.first
end
Console Output
User Load (1.0ms) SELECT DISTINCT users.id, users.* FROM "users" WHERE "users"."id" = 3 LIMIT 1
(0.5ms) SELECT COUNT(count_column) FROM (SELECT 1 AS count_column FROM "outfits" WHERE (user_id != 3) LIMIT 8 OFFSET 0) subquery_for_count
Outfit Load (0.7ms) SELECT DISTINCT outfits.id, outfits.* FROM "outfits" WHERE (user_id != 3) ORDER BY outfits.created_at DESC LIMIT 8 OFFSET 0
OutfitItem Load (0.6ms) SELECT "outfit_items".* FROM "outfit_items" WHERE "outfit_items"."outfit_id" IN (28, 27, 26, 25, 24, 23, 22, 21)
Item Load (2.2ms) SELECT DISTINCT items.id, items.*, "items".* FROM "items" WHERE "items"."id" IN (18, 20, 23, 7, 6, 30, 4, 1, 17, 5, 15, 12, 9, 29, 10, 19, 3, 8, 13) ORDER BY items.created_at DESC
ItemCategory Load (0.5ms) SELECT "item_categories".* FROM "item_categories" WHERE "item_categories"."id" IN (4, 6, 2, 1, 3, 7)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (1.2ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.1ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (2.8ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (1.4ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.9ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (1.2ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.9ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (2.7ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.8ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.7ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (1.2ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (1.1ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (2.2ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.8ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (3.4ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.0ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (2.6ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_secondary_item.html.haml (0.3ms)
Rendered outfits/_other_users_outfit_primary_item.html.haml (2.1ms)
Rendered outfits/_other_users_outfit.html.haml (56.3ms)
(0.5ms) SELECT COUNT(*) FROM "outfits" WHERE (user_id != 3)
Rendered outfits/other_users.html.haml within layouts/application (2073.5ms)
Role Load (0.4ms) SELECT "roles".* FROM "roles" WHERE "roles"."name" = 'admin' LIMIT 1
(0.4ms) SELECT 1 FROM "roles" INNER JOIN "roles_users" ON "roles"."id" = "roles_users"."role_id" WHERE "roles_users"."user_id" = 3 AND "roles"."id" = 1 LIMIT 1
Rendered layouts/_top_nav.html.haml (1.0ms)
(0.6ms) SELECT COUNT(*) FROM "items" WHERE "items"."user_id" = 3
Rendered layouts/_points_display.html.haml (5.7ms)
Outfit Load (0.6ms) SELECT DISTINCT outfits.id, outfits.* FROM "outfits" WHERE "outfits"."user_id" = 3 ORDER BY outfits.created_at DESC
OutfitCategory Load (0.3ms) SELECT "outfit_categories".* FROM "outfit_categories"
.
Any help would be much appreciated!

Answer 1

The only thing I see that could stand improvement is the code in the helper. Is there a reason why you're doing this:
def outfit_item_in_category(outfit, cat_name)
outfit.items.select{|item| item.category.name == cat_name }.first
end
instead of pushing this code to a scope in the Item model? If you have a lot of items, you're basically doing a SELECT * on them and then filtering in Ruby.