Batch-loader or preloading with destroy and dependent: :destroy associations N+1 problems.

[ghost]

In Rails there is the model.destroy(id) command to delete (with callbacks) a model. Good.

But when you use dependent: :destroy with has_many or has_one it has fun never ending with N+1 queries!!! :(

Especially if I use polymorhpic associations.

See this:

Started POST "/api/v1" for 172.18.0.1 at 2017-12-28 00:05:38 +0000
Processing by GraphqlController#execute as */*
  Parameters: {"query"=>"mutation deleteProductMutation {\n  deleteProduct(id: 1) {\n    id\n  }\n}\n", "graphql"=>{"query"=>"mutation deleteProductMutation {\n  deleteProduct(id: 1) {\n    id\n  }\n}\n"}}
  User Load (1.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Product Load (0.4ms)  SELECT  "products".* FROM "products" WHERE "products"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
   (0.3ms)  BEGIN
  Team Load (0.4ms)  SELECT  "teams".* FROM "teams" WHERE "teams"."product_id" = $1 LIMIT $2  [["product_id", 1], ["LIMIT", 1]]
  MotherItem Load (0.5ms)  SELECT "game_items".* FROM "game_items" WHERE "game_items"."team_id" = $1  [["team_id", 1]]
  PlayerProfile Load (1.3ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 1], ["profileable_type", "MotherItem"], ["LIMIT", 1]]
  SQL (0.5ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 1]]
  SQL (0.3ms)  DELETE FROM "game_items" WHERE "game_items"."id" = $1  [["id", 1]]
  PlayerProfile Load (0.5ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 2], ["profileable_type", "MotherItem"], ["LIMIT", 1]]
  SQL (0.6ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 2]]
  SQL (0.8ms)  DELETE FROM "game_items" WHERE "game_items"."id" = $1  [["id", 2]]
  PlayerProfile Load (0.6ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 3], ["profileable_type", "MotherItem"], ["LIMIT", 1]]
  SQL (0.5ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 3]]
  SQL (0.3ms)  DELETE FROM "game_items" WHERE "game_items"."id" = $1  [["id", 3]]
  PlayerItem Load (0.5ms)  SELECT "sister_items".* FROM "sister_items" WHERE "sister_items"."team_id" = $1  [["team_id", 1]]
  PlayerProfile Load (0.5ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 1], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (0.4ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 4]]
  SQL (0.4ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 1]]
  PlayerProfile Load (0.6ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 2], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (0.5ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 5]]
  SQL (0.7ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 2]]
  PlayerProfile Load (0.4ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 3], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (0.3ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 6]]
  SQL (0.3ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 3]]
  PlayerProfile Load (0.4ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 4], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (1.4ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 7]]
  SQL (0.5ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 4]]
  PlayerProfile Load (0.5ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 5], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (0.5ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 8]]
  SQL (0.5ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 5]]
  PlayerProfile Load (0.4ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 6], ["profileable_type", "PlayerItem"], ["LIMIT", 1]]
  SQL (1.3ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 9]]
  SQL (1.9ms)  DELETE FROM "sister_items" WHERE "sister_items"."id" = $1  [["id", 6]]
  FootballItem Load (1.4ms)  SELECT "football_items".* FROM "football_items" WHERE "football_items"."team_id" = $1  [["team_id", 1]]
  PlayerProfile Load (1.0ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 1], ["profileable_type", "FootballItem"], ["LIMIT", 1]]
  SQL (0.6ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 10]]
  SQL (1.8ms)  DELETE FROM "football_items" WHERE "football_items"."id" = $1  [["id", 1]]
  PlayerProfile Load (0.3ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 2], ["profileable_type", "FootballItem"], ["LIMIT", 1]]
  SQL (1.0ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 11]]
  SQL (0.4ms)  DELETE FROM "football_items" WHERE "football_items"."id" = $1  [["id", 2]]
  PlayerProfile Load (0.4ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 3], ["profileable_type", "FootballItem"], ["LIMIT", 1]]
  SQL (0.6ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 12]]
  SQL (0.6ms)  DELETE FROM "football_items" WHERE "football_items"."id" = $1  [["id", 3]]
  PlayerProfile Load (0.9ms)  SELECT  "player_profiles".* FROM "player_profiles" WHERE "player_profiles"."profileable_id" = $1 AND "player_profiles"."profileable_type" = $2 LIMIT $3  [["profileable_id", 4], ["profileable_type", "FootballItem"], ["LIMIT", 1]]
  SQL (0.6ms)  DELETE FROM "player_profiles" WHERE "player_profiles"."id" = $1  [["id", 13]]
  SQL (0.3ms)  DELETE FROM "football_items" WHERE "football_items"."id" = $1  [["id", 4]]
  SQL (2.7ms)  DELETE FROM "teams" WHERE "teams"."id" = $1  [["id", 1]]
  SQL (2.6ms)  DELETE FROM "products" WHERE "products"."id" = $1  [["id", 1]]
   (3.3ms)  COMMIT
Completed 200 OK in 522ms (Views: 0.4ms | ActiveRecord: 80.5ms)

user: root
POST /api/v1
USE eager loading detected
  MotherItem => [:player_profile]
  Add to your finder: :includes => [:player_profile]
Call stack
  /app/graphql/delete.rb:15:in `call'
  /app/controllers/graphql_controller.rb:11:in `execute'

user: root
POST /api/v1
USE eager loading detected
  PlayerItem => [:player_profile]
  Add to your finder: :includes => [:player_profile]
Call stack
  /app/graphql/delete.rb:15:in `call'
  /app/controllers/graphql_controller.rb:11:in `execute'

user: root
POST /api/v1
USE eager loading detected
  FootballItem => [:player_profile]
  Add to your finder: :includes => [:player_profile]
Call stack
  /app/graphql/delete.rb:15:in `call'
  /app/controllers/graphql_controller.rb:11:in `execute'

As you can see gem Bullet (https://github.com/flyerhzm/bullet) detects N+1 problems...

Is there a way to handle this? Maybe with the same gem for batching and preloader? (https://github.com/Shopify/graphql-batch) - (https://github.com/ConsultingMD/graphql-preload) ?