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Rails
ΞϓϦͷ
5,000
݅ͷ
N+1
ͱ
ઓ͍ͬͯΔ
2023.10.27.
Kaigi on Rails 2023
@makicamel
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͓ͼ
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No content
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ͳ͗ͤ
·ͤΜͰͨ͠
💧
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͓Εͨͪͷઓ͍
͔͜͜Βͩ
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Rails
ΞϓϦͷ
5,000
݅ͷ
N+1
ͱ
ઓ͍ͬͯΔ
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ࣗݾհ
w!NBLJDBNFMݪສق
w3VCZͱϏʔϧɹɹͱ͓ञ͕͖
w͖ͳ73ήʔϜ
w
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N+1
͋Γ·͔͢ʁ
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N+1
Կ݅͋Γ·͔͢ʁ
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N+1 ͱ
͔ΜͨΜͳ
͓͞Β͍
͔ΜͨΜͳ
આ໌༻Ϟσϧ
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plays = Play.limit(10)
plays.each do |play|
puts play.actors.map(&:name)
end
SELECT "plays".* FROM "plays" LIMIT 10
SELECT "actors".* FROM "actors"
INNER JOIN "play_actors" ON "actors"."id" = "play_actors"."actor_id"
WHERE "play_actors"."play_id" = 1
SELECT "actors".* FROM "actors"
INNER JOIN "play_actors" ON "actors"."id" = "play_actors"."actor_id"
WHERE "play_actors"."play_id" = 2
SELECT "actors".* FROM "actors"
INNER JOIN "play_actors" ON "actors"."id" = "play_actors"."actor_id"
WHERE "play_actors"."play_id" = 3
...
10 + 1 ճͷΫΤϦ͕ൃߦ͞ΕΔ
N+1 ͱ
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N+1 ରࡦ
•ActiveRecord::QueryMethods#preload
•ActiveRecord::QueryMethods#eager_load
•ActiveRecord::QueryMethods#includes
Rails ฤ 🛤
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ActiveRecord::QueryMethods#preload
plays = Play.preload(:actors).limit(10)
plays.each do |play|
puts play.actors.map(&:name)
end
SELECT "plays".* FROM "plays" LIMIT 10
SELECT "play_actors".* FROM "play_actors"
WHERE "play_actors"."play_id" IN (1, 2, 3, ...)
SELECT "actors".* FROM "actors"
WHERE "actors"."id" IN (1, 2, 3, ...)
3 ͭʹ͚ΒΕͨΫΤϦ͕ൃߦ͞ΕΔ
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ActiveRecord::QueryMethods#eager_load
plays = Play.eager_load(:actors).limit(10)
plays.each do |play|
puts play.actors.map(&:name)
end
SELECT DISTINCT "plays"."id" FROM "plays"
LEFT OUTER JOIN "play_actors" ON "play_actors"."play_id" = "plays"."id"
LEFT OUTER JOIN "actors" ON "actors"."id" = "play_actors"."actor_id"
LIMIT 10
SELECT "plays"."id" AS t0_r0, ... FROM "plays"
LEFT OUTER JOIN "play_actors" ON "play_actors"."play_id" = "plays"."id"
LEFT OUTER JOIN "actors" ON "actors"."id" = "play_actors"."actor_id"
WHERE "plays"."id" IN (1, 2, 3, ...)
LEFT OUTER JOIN ͨ͠
ΫΤϦ͕ൃߦ͞ΕΔ
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ActiveRecord::QueryMethods#includes
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ActiveRecord::QueryMethods#includes
ActiveRecord::QueryMethods#includes
https://api.rubyonrails.org/classes/ActiveRecord/QueryMethods.html#method-i-includes
ຊޠൃදऀ༁
Specify associations args to be eager loaded to prevent N + 1 queries.
A separate query is performed for each association,
unless a join is required by conditions.
N + 1 ΫΤϦΛ͙ͨΊʹ args associations Λ eager_load ͢ΔΑ͏ࢦఆ͠·͢ɻ
݅ʹΑͬͯ join ͕ඞཁͰͳ͚Εɺ
֤ association ͝ͱʹݸผͷΫΤϦ͕࣮ߦ͞Ε·͢ɻ
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ActiveRecord::QueryMethods#includes
ActiveRecordͷjoinsͱpreloadͱincludesͱeager_loadͷҧ͍ / @k0kubun
https://qiita.com/k0kubun/items/80c5a5494f53bb88dc58
•includes ͨ͠ςʔϒϧͰ where ʹΑΔߜΓࠐΈΛߦ͍ͬͯΔ
•includes ͨ͠ association ʹରͯ͠ joins ͔ references ݺΜͰ͍Δ
•ҙͷ association ʹରͯ͠ eager_load ݺΜͰ͍Δ
ͷ͏͍ͪͣΕ͔Λຬͨ͢߹ɺeager_load ͱಉ͡ڍಈ(LEFT JOIN)Λߦ͍ɺ
ͦ͏Ͱͳ͚Ε preload ͱಉ͡ڍಈ(ΫΤϦΛ͚࣮ͯߦ)Λ͢Δɻ
ߜΓࠐΈ͕ඞཁͳ࣌ʹྫ֎Λ͛ͣ eager_load ʹfallback͢Δ preloadɻ
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N+1 ରࡦ
gem ฤ 💎
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Bullet 🔫
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fl
yerhzm / bullet
https://github.com/
fl
yerhzm/bullet
Bullet 🔫
ɹN+1 ෆཁͳ eager_loadingͳͲΛ
ɹϩάը໘ʹදࣔͯ͠ڭ͑ͯ͘ΕΔ
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# config/environments/test.rb
Rails.application.configure do
config.after_initialize do
Bullet.enable = true
Bullet.raise = true
end
end
Bullet 🔫
ɹraise Λࢦఆ͢ΔͱΤϥʔΛى͜͢
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N+1
Կ݅͋Γ·͔͢ʁ
ʢ࠶ܝʣ
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※ unused eager_loading ͱ counter cache ͷؚΈ·͢
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4722 tests failed
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ߕຊҰ / Ϛογϡϧ-MASHLE-
https://mashle.pw
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ͭͬͨ͘ 🩹
makicamel / bulletmark_repairer
https://github.com/makicamel/bulletmark_repairer
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ͭͬͨ͘ 🩹
makicamel / bulletmark_repairer
https://github.com/makicamel/bulletmark_repairer
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BulletmarkRepairer 🩹
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
N+1 ൃੜ
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BulletmarkRepairer 🩹
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
N+1 ൃੜ
$ REPAIR=1 rspec
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BulletmarkRepairer 🩹
class PlaysController < ApplicationController
def index
@plays = Play.all.includes([:actors])
end
end
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
ɹ࣮ߦ࣌ʹ autocorrect Ͱ
ɹincludes ΛՃ͢Δ
$ REPAIR=1 rspec
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BulletmarkRepairer ͷ
ͭ͘Γํ 🛠
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ྩͷ࣌ʹ
खͰ includes ॻ͘ͷ
໘͍͘͞
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Bullet ͕ N+1 Λݕͨ͠Β
includes Λఴͨ͠Β
͍͍Μ͡Όͳ͍ʁ
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•Ͳ͜Ͱ includes ͢Δ͖͔
•ͳʹΛ includes ͢Δ͖͔
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•Ͳ͜Ͱ includes ͢Δ͖͔
•ͳʹΛ includes ͢Δ͖͔
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Case 1.
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
ɹϏϡʔͰ N+1 ͕
ɹൃੜ͢Δέʔε
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Case 1.
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
<% @plays.includes(:actors).each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
ɹϏϡʔͰ
ɹincludes ͨ͘͠ͳ͍ 🙅
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Case 1.
class PlaysController < ApplicationController
def index
@plays = Play.all.includes(:actors)
end
end
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
ɹίϯτϩʔϥͰ
ɹincludes ͍ͨ͠ 🙆
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Case 2.
class PlaysController < ApplicationController
def index
plays = Play.all.map do |play|
{
title: play.name,
actors: play.actors.map(&:name)
}
end
render json: { data: plays }
end
end
ɹίϯτϩʔϥͰ
ɹൃੜ͢Δέʔε
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Case 2.
class PlaysController < ApplicationController
def index
plays = Play.all.includes(:actors).map do |play|
{
title: play.name,
actors: play.actors.map(&:name)
}
end
render json: { data: plays }
end
end
ɹίϯτϩʔϥͰ
ɹ͢ͱΑͦ͞͏ 🙆
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Case 3.
class PlaysController < ApplicationController
before_action :set_plays
def index
render json: { data: @plays.as_json }
end
private
def set_plays
@plays = Play.all
end
end
ɹίʔϧόοΫͰ
ɹActiveRecord Λ
ɹΈཱͯΔέʔε
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Case 3.
class PlaysController < ApplicationController
before_action :set_plays
def index
render json: { data: @plays.as_json }
end
private
def set_plays
@plays = Play.all.includes(:actors)
end
end
ɹ͜ͷ߹
ɹίʔϧόοΫͰͯ͠
ɹΑͦ͞͏ 🙆
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Case 4.
class PlaysController < ApplicationController
def index
render json: { data: scope.as_json }
end
def show
render json: { data: scope.find(params[:id]).as_json }
end
private
def scope
Play.where('name like ?', params[:name])
end
end
ɹڞ௨ͷείʔϓΛ
ɹ͍ͬͯΔ߹
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Case 4.
class PlaysController < ApplicationController
def index
render json: { data: scope.as_json }
end
def show
render json: { data: scope.find(params[:id]).as_json }
end
private
def scope
Play.where('name like ?', params[:name])
end
end
ɹΞΫγϣϯͰ
ɹ͖͢…ʁ🤔
ɹ͜ͷ͘Β͍ͳΒ
ɹείʔϓͰͯ͠
ɹΑͦ͞͏͚ͩͲ…🤔
ɹshow Ͱ includes ͢Δ
ɹඞཁͳ͘ͳ͍ʁ🤔
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Case 5.
ɹίϯτϩʔϥ͔Β
ɹݺͼग़ͨ͠
ɹϞσϧͷϝιουͰ
ɹN+1 ͕ൃੜ͢Δέʔε
class PlaysController < ApplicationController
def index
plays = Play.all
render json: { data: plays.map(&:as_json_with_actors) }
end
end
class Play < ApplicationRecord
def as_json_with_actors
as_json.merge(actors: actors.map(&:name))
end
end
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Case 5.
class PlaysController < ApplicationController
def index
plays = Play.all.includes(:actors)
render json: { data: plays.map(&:as_json_with_actors) }
end
end
class Play < ApplicationRecord
def as_json_with_actors
as_json.merge(actors: actors.map(&:name))
end
end
ɹίϯτϩʔϥͰ
ɹ͢ͱΑͦ͞͏ 🙆
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Case 6.
ɹϞσϧͷίʔϧόοΫͰ
ɹΫΤϦ্ͨ͠͠Ͱ
ɹൃੜ͍ͯ͠Δέʔε
class Play < ApplicationRecord
after_save :notify_actors, if: :notification_required?
private
def notify_actors
actors.where(...).each(&:notify!)
end
end
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Case 6.
class Play < ApplicationRecord
after_save :notify_actors, if: :notification_required?
private
def notify_actors
actors.where(...).includes(:actors).each(&:notify!)
end
end
ɹϞσϧͰ
ɹ͢ͱΑͦ͞͏ʁ
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Case 7.
class TransitionPastPlaysService
def initialize(border_date)
@border_date = border_date
end
def execute
plays = Play.where(created_at: ..@border_date)
play_actors = plays.map do |play|
{
play_id: play.id,
actor_id: play.actors.map(&:id)
}
end
PastPlay.insert_all plays.map(&:as_json)
PastPlayActor.insert_all play_actors
plays.destroy_all
end
end
ɹαʔϏεͰ
ɹPlay.where ্ͨ͠Ͱ
ɹൃੜ͢Δέʔε
※ ຊདྷ map(&:id) Ͱͳ͘ pluck(:id) ids Λ͑ N+1 ͷӨڹখ͘͞ͳΓ·͢
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Case 7.
class TransitionPastPlaysService
def initialize(border_date)
@border_date = border_date
end
def execute
plays = Play.where(created_at: ..@border_date).includes(:actors)
play_actors = plays.map do |play|
{
play_id: play.id,
actor_id: play.actors.map(&:id)
}
end
PastPlay.insert_all plays.map(&:as_json)
PastPlayActor.insert_all play_actors
plays.destroy_all
end
end
※ ຊདྷ map(&:id) Ͱͳ͘ pluck(:id) ids Λ͑ N+1 ͷӨڹখ͘͞ͳΓ·͢
ɹαʔϏεͰ
ɹ͔͢͠ͳ͍
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ۚాҰগͷࣄ݅֎ ൜ਓͨͪͷࣄ݅
ఱथؙݪҊ ધਈฏݪҊ ͞ͱ͏;ΈݪҊ ۚཅࡾອը
ߟ
͑
Δ
ߟ
͑
Δ
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•ίϯτϩʔϥͰ includes ͢Δͷਖ਼ͦ͠͏
•ෳͷΞΫγϣϯͰڞ௨είʔϓΛར༻͍ͯ͠Δ߹ʁ
•ϏϡʔͰ includes ͢Δͷ·͘͠ͳͦ͞͏
•ϞσϧͷΠϯελϯεϝιουΑΓίϯτϩʔϥͰ includes͍ͨ͠
•ϝιουͰΫΤϦ͍ͯ͠͠Δ߹ʁ
•αʔϏεΫϥε etc …
Ͳ͜Ͱ includes ͢Δ͖͔
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Ϝζ͍ 😇
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;ͩΜ
Ͳ͏ͯ͠Δ͚ͬʁ
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•جຊతʹίϯτϩʔϥͰ includes ͢Δ
•ϓϥΠϕʔτϝιουΑΓΞΫγϣϯͰ includes ͢Δ͜ͱ͕ଟ͍
•ActiveRecord ͷΈཱͯॳظͰ includes ͢Δ͜ͱ͕ଟ͍
•ΉΛಘͳ͚ΕϞσϧɾαʔϏεΫϥε etc Ͱ includes ͢Δ
;ͩΜͷࢥߟճ࿏
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;ͩΜͷࢥߟճ࿏
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;ͩΜͷࢥߟճ࿏
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
ɹBullet ͷϩά
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹελοΫτϨʔεʹ
ɹίϯτϩʔϥ͕ͳ͍
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹमਖ਼͍ͨ͠ϑΝΠϧ
ɹͬͪ͜
ɹελοΫτϨʔεʹ
ɹίϯτϩʔϥ͕ͳ͍
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹϏϡʔͰ N+1 Λൃੜͤ͞Δ
ɹଟ͘ͷ߹Πϯελϯεมʹೖ͍ͬͯΔ
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹN+1 ൃੜߦΘ͔Δ
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹରͬΆ͍
ɹΠϯελϯεม͕Θ͔Δʢצʣ
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹURL ͕Θ͔Δ
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Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹίϯτϩʔϥͱ
ɹΞΫγϣϯ͕Θ͔Δ
Slide 67
Slide 67 text
Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹΠϯελϯεมʹ
ɹೖ͢Δͱ͜Ζʹ
Slide 68
Slide 68 text
Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
class PlaysController < ApplicationController
def index
@plays = Play.all.includes(:actors)
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:2:in `block in _app_views_plays
_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/
index.html.erb:1:in `_app_views_plays
_index_html_erb__3206924200111145907_11500’
ɹincludes Λ͢✌
Slide 69
Slide 69 text
Ϗϡʔฤ
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<% if @favorite %>
<%= actor.name %>
<% end %>
<% end %>
<% end %> ରͷΠϯελϯεม
צͰ୳͍ͯ͠ΔͷͰ
͜Μͳίʔυͩͱಈ͔ͳ͍
N+1 ൃੜՕॴ
ΠϯελϯεมΆ͍
จࣈྻͦͷ 1ʢμτʣ
ΠϯελϯεมΆ͍
จࣈྻͦͷ 2ʢຊʣ
Slide 70
Slide 70 text
Ϗϡʔฤ
<% Play.all.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
ΠϯελϯεมΛ
લఏͱ͍ͯ͠ΔͷͰ
͜Μͳίʔυಈ͔ͳ͍
Slide 71
Slide 71 text
Ϗϡʔฤ
Slide 72
Slide 72 text
;ͩΜͷࢥߟճ࿏
Slide 73
Slide 73 text
ίϯτϩʔϥฤ
•͍͔ͭ͘ύλʔϯ͕͋Γͦ͏
Slide 74
Slide 74 text
ίϯτϩʔϥฤ
class PlaysController < ApplicationController
def index
plays = Play.all.map do |play|
{
title: play.name,
actors: play.actors.map(&:name)
}
end
render json: { data: plays }
end
end
ɹ͜͜Ͱ includes ͢Δͱ
ɹΑͦ͞͏
Slide 75
Slide 75 text
ίϯτϩʔϥฤ
class PlaysController < ApplicationController
def index
@plays = scope
if params[:future]
@plays = @plays.where(performed_at: Date.today..)
end
gon.as_json = @plays.as_json
end
def show
@play = scope.find(params[:id])
end
private
def scope
Actor.find(params[:actor_id]).plays
end
end
ɹ͜͜Ͱ includes ͢Δͱ
ɹΑͦ͞͏
Slide 76
Slide 76 text
ίϯτϩʔϥฤ
class PlaysController < ApplicationController
before_action :set_plays
def index
render json: { data: @plays.as_json }
end
private
def set_plays
@plays = Play.all
end
end
ɹ͜͜Ͱ includes ͢Δͱ
ɹΑͦ͞͏ʁ
Slide 77
Slide 77 text
ίϯτϩʔϥฤ
Slide 78
Slide 78 text
ίϯτϩʔϥฤ
ɹ͍ͬͨΜ
ɹޙճ͠
Slide 79
Slide 79 text
ίϯτϩʔϥฤ
ɹϩά͔ΒURL ͕Θ͔ΔͷͰ
ɹίϯτϩʔϥͱ
ɹΞΫγϣϯ͕Θ͔Δ
Slide 80
Slide 80 text
ίϯτϩʔϥฤ
class PlaysController < ApplicationController
def index
@plays = scope
if params[:future]
@plays = @plays.where(performed_at: Date.today..)
end
gon.as_json = @plays.as_json
end
def show
@play = scope.find(params[:id])
end
private
def scope
Actor.find(params[:actor_id]).plays
end
end
ɹͻͱͭͷϝιουͰ
ɹෳճೖ͞Ε͍ͯΔ߹
ɹͲͪΒ͕ਖ਼͍͔͠
ɹػձతͳఆແཧ
Slide 81
Slide 81 text
ίϯτϩʔϥฤ
class PlaysController < ApplicationController
def index
@plays = scope
if params[:future]
@plays = @plays.where(performed_at: Date.today..)
end
gon.as_json = @plays.as_json
end
def show
@play = scope.find(params[:id])
end
private
def scope
Actor.find(params[:actor_id]).plays
end
end
ɹ࠷ॳʹೖ͢Δ΄͏͕
ɹϢʔεέʔεͱͯ͠ଟͦ͏
Slide 82
Slide 82 text
ίϯτϩʔϥฤ
ɹ࠶ؼతʹϝιουΛνΣοΫ
ɹݟ͔ͭΒͳ͚Ε
ɹίʔϧόοΫΛνΣοΫ
Slide 83
Slide 83 text
ରͷΠϯελϯεม
Ϗϡʔಉ༷
צͰ୳ͯ͠·͢
ίϯτϩʔϥฤ
Slide 84
Slide 84 text
;ͩΜͷࢥߟճ࿏
Slide 85
Slide 85 text
ͦͷଞฤ
ɹBullet ͷϩά͔Β
ɹൃੜߦ͕Θ͔ΔͷͰ
ɹͦ͜Ͱमਖ਼
Slide 86
Slide 86 text
ίϯτϩʔϥฤ
ɹ͜ͷέʔε
ɹճऩ
Slide 87
Slide 87 text
•Ͳ͜Ͱ includes ͢Δ͖͔ ✓
•ͳʹΛ includes ͢Δ͖͔
Slide 88
Slide 88 text
•Ͳ͜Ͱ includes ͢Δ͖͔ ✓
•ͳʹΛ includes ͢Δ͖͔
Slide 89
Slide 89 text
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.name %>
<% end %>
<% end %>
<% @plays.each do |play| %>
<% play.actors.each do |actor| %>
<%= actor.company.name %>
<% end %>
<% end %>
ɹ͜Μͳײ͡ͷϏϡʔ͕
ɹ͋Δͱ͢Δ
Slide 90
Slide 90 text
Case 1.
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__3206924200111145907_11500'
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
ɹجຊέʔε
Slide 91
Slide 91 text
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_index_html_erb__3206924200111145907_11500'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__3206924200111145907_11500'
class PlaysController < ApplicationController
def index
@plays = Play.all.includes(:actors)
end
end
Case 1.
ɹجຊέʔε
Slide 92
Slide 92 text
Case 2.
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
ɹassociations ͕
ɹෳ͋Δέʔε
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:theaters]
Add to your query: .includes([:theaters])
Slide 93
Slide 93 text
class PlaysController < ApplicationController
def index
@plays = Play.all.includes([:actors, :theaters])
end
end
Case 2.
ɹassociations ͕
ɹෳ͋Δέʔε
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:theaters]
Add to your query: .includes([:theaters])
Slide 94
Slide 94 text
Case 3.
2023-10-26 14:37:36[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [{:actors=>[:company]}]
Add to your query: .includes([:"{:actors=>[:company]}"])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_index_html_erb__1665884924136242781_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_plays_index_html_erb__1665884924136242781_11760'
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
ɹωετ͍ͯ͠Δέʔε
Slide 95
Slide 95 text
Case 3.
2023-10-26 14:37:36[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [{:actors=>[:company]}]
Add to your query: .includes([:"{:actors=>[:company]}"])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_index_html_erb__1665884924136242781_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_plays_index_html_erb__1665884924136242781_11760'
class PlaysController < ApplicationController
def index
@plays = Play.all.includes([{:actors=>[:company]}])
end
end
ɹωετ͍ͯ͠Δέʔε
Slide 96
Slide 96 text
Case 4.
2023-10-26 14:57:19[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:awesome_actors]
Add to your query: .includes([:awesome_actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_html_erb___4265071383862059390_11760’
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb___4265071383862059390_11760'
class PlaysController < ApplicationController
def index
@plays = Play.all
end
end
ɹωετ͍ͯ͠Δ͔ͭ
ɹassociation ʹผ໊͕͋Δέʔε
class Play < ApplicationRecord
has_many :play_actors
has_many :awesome_actors,
through: :play_actors,
source: :actor
end
Slide 97
Slide 97 text
class PlaysController < ApplicationController
def index
@plays = Play.all.includes({:awesome_actors=>[:company]})
end
end
Case 4.
2023-10-26 14:57:19[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:awesome_actors]
Add to your query: .includes([:awesome_actors])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block in
_app_views_plays_html_erb___4265071383862059390_11760’
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb___4265071383862059390_11760'
ɹωετ͍ͯ͠Δ͔ͭ
ɹassociation ʹผ໊͕͋Δέʔε
class Play < ApplicationRecord
has_many :play_actors
has_many :awesome_actors,
through: :play_actors,
source: :actor
end
Slide 98
Slide 98 text
Case 5.
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors)
end
end
ɹҰ෦ includes ࡁͷέʔε
Slide 99
Slide 99 text
Case 5.
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors).includes({:actors=>[:company]})
end
end
ɹҰ෦ includes ࡁͷέʔε
Slide 100
Slide 100 text
AssociationsBuilder
Slide 101
Slide 101 text
AssociationsBuilder
module BulletmarkRepairer
class AssociationsBuilder
def build(marker)
return if marker.skip?
if associations[marker.index]
associations[marker.index].add(marker)
else
associations[marker.index] = Associations.new(
marker,
@application_associations,
@loaded_associations
)
end
end
end
end
ɹBullet ͷܯࠂΛநԽͨ͠
ɹΠϯελϯε
Slide 102
Slide 102 text
AssociationsBuilder
module BulletmarkRepairer
class AssociationsBuilder
def build(marker)
return if marker.skip?
if associations[marker.index]
associations[marker.index].add(marker)
else
associations[marker.index] = Associations.new(
marker,
@application_associations,
@loaded_associations
)
end
end
end
end
ɹN+1 ൃੜՕॴΛΩʔʹͯ͠
ɹ ɹ
Slide 103
Slide 103 text
AssociationsBuilder
module BulletmarkRepairer
class AssociationsBuilder
def build(marker)
return if marker.skip?
if associations[marker.index]
associations[marker.index].add(marker)
else
associations[marker.index] = Associations.new(
marker,
@application_associations,
@loaded_associations
)
end
end
end
end
ɹN+1 ൃੜՕॴΛΩʔʹͯ͠
ɹassociation ΛΈཱͯΔ
Slide 104
Slide 104 text
AssociationsBuilder
module BulletmarkRepairer
class AssociationsBuilder
def build(marker)
return if marker.skip?
if associations[marker.index]
associations[marker.index].add(marker)
else
associations[marker.index] = Associations.new(
marker,
@application_associations,
@loaded_associations
)
end
end
end
end
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:actors]
Add to your query: .includes([:actors])
2023-10-23 07:21:04[WARN] user: makicamel
GET /plays
USE eager loading detected
Play => [:theaters]
Add to your query: .includes([:theaters])
ɹෳͷܯࠂΛ
ɹͻͱͭʹ·ͱΊ͍ͨ
ɹέʔε͕͋Δ
Slide 105
Slide 105 text
AssociationsBuilder
•γϯϘϧΛϋογϡʹͨ͠Γ
[:actor]ɹˠɹ[{ actor: [:company] }]
•ϋογϡͷόϦϡʔΛྻʹมͯ͠ΛՃͨ͠Γ
[{ actors: :company }, :staffs]
ɹˠɹ[{ actors: [:company, :works] }, :staffs]
•ྻͷͷͻͱͭͱՃ͍ͨ͠Λϋογϡʹมͨ͠Γ
[{ actors: :works }]ɹˠɹ[{ actors: { works: [:staffs] } }]
ͳΜ͔͍ͯ͠Δ
ɹෳͷܯࠂΛ
ɹͻͱͭʹ·ͱΊ͍ͨ
ɹέʔε͕͋Δ
Slide 106
Slide 106 text
LoadedAssociations
Slide 107
Slide 107 text
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors)
end
end
ɹҰ෦ includes ࡁͷέʔε
LoadedAssociations
Slide 108
Slide 108 text
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors).includes({:actors=>[:company]})
end
end
ɹҰ෦ includes ࡁͷέʔε
LoadedAssociations
Slide 109
Slide 109 text
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors).includes({:actors=>[:company]})
end
end
ɹBullet ͷܯࠂ͔Β
ɹ@plays ͷϕʔεͷΫϥε͕
ɹԿ͔Θ͔Βͳ͍
LoadedAssociations
Slide 110
Slide 110 text
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
ɹBullet ͷܯࠂ͔ΒͲͪΒ͕
ɹਖ਼͍͔͠Θ͔Βͳ͍
LoadedAssociations
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors).includes({:actors=>[:company]})
end
end
.includes([:company])
Slide 111
Slide 111 text
LoadedAssociations
module BulletmarkRepairer
module ActiveRecord
module QueryMethod
def includes(*args)
Thread.current[:bulletmark_repaier_loaded_associations][model.name][:includes].add(args)
super(args)
end
def eager_load(*args)
Thread.current[:bulletmark_repaier_loaded_associations][model.name][:eager_load].add(args)
super(args)
end
def preload(*args)
Thread.current[:bulletmark_repaier_loaded_associations][model.name][:preload].add(args)
super(args)
end
end
end
end
ɹಡΈࠐΈࡁͷ associations Λ
ɹϝϞ͓ͯ͘͠
Slide 112
Slide 112 text
LoadedAssociations
ɹassociation ΛΈཱͯΔ࣌ʹ
ɹࢀর͢Δ
class Associations
def initialize(marker, application_associations, loaded_associations)
@marker = marker
@application_associations = application_associations
@loaded_associations = loaded_associations
key = @loaded_associations.key(marker.base_class)
@associations = { base: key ? { key => marker.associations } : marker.associations }
end
end
Slide 113
Slide 113 text
2023-10-26 14:46:46[WARN] user: makicamel
GET /plays
USE eager loading detected
Actor => [:company]
Add to your query: .includes([:company])
Call stack
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:3:in `block
(2 levels) in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:2:in `block
in _app_views_plays_index_html_erb__2119670124553133993_11760'
/Users/makicamel/awesome_app/app/views/plays/index.html.erb:1:in
`_app_views_plays_index_html_erb__2119670124553133993_11760'
ɹactors includes ࡁͳͷͰ
ɹωετ͢Δͷ͕ਖ਼͍͠ 💡
LoadedAssociations
class PlaysController < ApplicationController
def index
@plays = Play.includes(:actors).includes({:actors=>[:company]})
end
end
.includes([:company])
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•Ͳ͜Ͱ includes ͢Δ͖͔ ✓
•ͳʹΛ includes ͢Δ͖͔ ✓
͋ͱ Parer ʹ͓ͤ
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☕
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ͨͿΜΈͳ͞Μ͕ؾʹͳ͍ͬͯΔ͜ͱ
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includes vs. preload or eager_load
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includes vs. preload or eager_load
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ൃߦ͞ΕΔΫΤϦ͕มΘΔ݅ࣗ໌ͳͷʹ
Ͳ͏͍͚͍ͯͨ͠Μ͚ͩͬʁ
includes vs. preload or eager_load
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•preload ͕·͍͠έʔε͕ଟ͍
•eager_load LEFT OUTER JOIN ͳͷͰϝϞϦΛ৯͍͍͢
•preload ͷ߹ IN ۟ʹೖΔ id ͷ͕ଟ͘ʢe.g. ສ݅ʣͳΔͱ
ύϑΥʔϚϯε͕ஶ͘͠Լ͢Δ͜ͱ͕͋Δ
•preload or eager_load Ҏ֎ͷํ๏͋Δ
preload vs. eager_load
ઈରղͳ͍
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•includes ͩͱύϥϝʔλঢ়ଶʹΑΓ preload or eager_load ͕
͍͚ΒΕΔ͜ͱ͕͋Δ
•ϦΫΤετʹΑΓൃߦ SQL ͕มΘΔͱੳͮ͠Β͍
includes vs. preload or eager_load
ੳɾӡ༻໘Ͱ includes ΑΓ preload or eager_load ͕·͍͠
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ϝϞϦѹഭ͕৺ͳΜͰ͚͢Ͳ...
N+1 → LEFT JOIN ͰϝϞϦ͕ʹͳΔͳΒ
ଟ͘ͷ߹ N+1 ͷ࣌Ͱ
ʹͳ͍ͬͯΔͱࢥ͍·͢Α
includes vs. preload or eager_load
@tricknotes
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N+1 < includes < preload or eager_load (or ͦͷଞ) ͷ͍͚
includes vs. preload or eager_load
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ݱ࣮ੈքͷ
N+1 ͱͷ͖߹͍ํ
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•͍͠
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•ΘΕΘΕ͍͠
•Γ͍ͨ͜ͱΛͯ͢Ͱ͖ΔΘ͚Ͱͳ͍
N+1 ͱͷ͖߹͍ํ
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•͖߹͑Δ࣌ʹ͖߹͑Δ
•৽͘͠ίʔυΛॻ࣌͘
•طଘͷίʔυΛ֦ு͢Δ࣌
•N+1 ͕ʹͳ͍ͬͯΔ࣌
N+1 ͱͷ͖߹͍ํ
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•͖߹͍ʹ͍࣌͘
•ࣗͷαʔϏεͰݩʑ͋ͬͨ N+1
•௨Γ͕͢Γʹݟ͚ͭͨ N+1
N+1 ͱͷ͖߹͍ํ
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•ͨ·ͨ·ݟ͚ͭͨطଘͷ N+1
•SQL ͷมߋϦεΩʔ
•צ͕ͳ͍ͱεϧʔ͕ͪ͠
•େ͖ͳαʔϏεʹͳΔͱྡͷͷ͜ͱΛΒͳ͔ͬͨΓ͢Δ
N+1 ͱͷ͖߹͍ํ
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ͷલʹ͝Έ͕མͪͯͨΒ
र͏͡Όͳ͍Ͱ͔͢
@a_matsuda
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ݱঢ়ͷANDPADͷվળ͍ͨ͠ͱ͜ΖΛ
ざ
ͬ͘
ば
ΒΜʹʢANDPAD ࣾ։࠵ʣ
2020 5 ݄ 22 @a_matsuda
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•ͨ·ͨ·ݟ͚ͭͨ N+1 ΛͱΓ͋͑ͣͯ͠ PR Λ࡞Δਓ
•PR ΛϤγ 👈 ͯ͠औΓࠐΉਓ
N+1 ୀ࣏൪
BulletmarkRepairer
͜ͷ෦ͷ
αϙʔτπʔϧ 🩹
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•ͨ·ͨ·ݟ͚ͭͨ N+1 ΛͱΓ͋͑ͣͯ͠ PR Λ࡞Δਓ
•PR ΛϤγ 👈 ͯ͠औΓࠐΉਓ
•ൃߦ͞ΕΔ SQL ͷมԽͷ֬ೝ
•࣮σʔλ্ͳͦ͞͏͔ͷ֬ೝ
͜ͷϓϩηεվળ
͔͚ͨͬͨ͠Ͳ
ؒʹ߹Θͳ͔ͬͨ
͜ͷϓϩηε
վળ͍ͨ͠
ʢؒʹ߹Θͳ͔ͬͨʣ
N+1 ୀ࣏൪
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N+1 ͱͷ͖߹͍ํ
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•શ෦ includes (preload or eager_load) ͢Εղܾ
•Ͱͳ͍
N+1 ͷղ๏
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•AR#present? → AR#exists? / AR#map → AR#pluck
N+1 ͷղ๏
దͳϝιουΛ
͏
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•e.g. Ұ෦ͷ݅࣌ͷΈಡΈࠐΜͩϨίʔυ͕ར༻͞ΕΔέʔε
→ ෆཁͳΒಡΈࠐ·ͳ͍
•e.g. ϙϦϞʔϑΟοΫؔ࿈ͷ
ಛఆͷؔ࿈ͰͷΈϨίʔυ͕ར༻͞ΕΔέʔε
→ ෆཁͳΒಡΈࠐ·ͳ͍
N+1 ͷղ๏
ෆཁͳΒ
ಡΈࠐ·ͳ͍
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•ղ๏༷ʑ
•୯७Ͱୀ۶ͳͷ
•ͯ͘͠಄ʹͯ͠ؤுΔͷ
N+1 ͱͷ͖߹͍ํ
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N+1 ͱͷ͖߹͍ํ
Ruby
ୀ۶ͳ͜ͱPythonʹΒͤΑ͏ɹϊϯϓϩάϥϚʔʹͰ͖ΔࣗಈԽॲཧϓϩάϥϛϯά
Al Sweigart ஶ ૬ Ѫࡾ ༁
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•୯७Ͱୀ۶ͳ͜ͱ Ruby ʹΒͤΑ͏
•ͯ͘͠໘ന͍ਓ͕ؒղ͜͏
N+1 ͱͷ͖߹͍ํ
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໘ന͍͜ͱΛ͍͖ͬͯ·͠ΐ͏
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͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠
Special Thanks
@tricknotes
@ydah
@l15n
@ken3ypa
@pupupopo88