Question

class Comment
  belongs_to :owner
  belongs_to :parent # parent/children from the gem awesome_nested_set
  has_many :children # 
end

class Car
  has_many :comments
end

所有者可以是Team或User或Group。他们每个人都有name，avatar（carrierwave）和created_at

属性

问题：

我们确实使用ActiveModel::Serializer作为回复。（CommentSerializer）。在序列化器中，我们定义了belongs_to :owner和has_many :children。

render json: car.comments

这很有效，但考虑到一组100条评论（其中大多数都有儿童评论），它远远没有表现良好。所以我们可以轻松查找300多个用户/团队/组协会。

我们如何预加载它们？我正在考虑像

这样的事情

car.comments.include(:children, :owner)但是这对于多态关联有什么用呢？

[active_model_serializers]   User Load (7.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 2 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 37 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.3ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 1 LIMIT 1
[active_model_serializers]   Action::Comment Load (3.1ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 39 ORDER BY `comments`.`lft`
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 2 LIMIT 1  [["id", 2], ["LIMIT", 1]]
[active_model_serializers]   Action::Comment Load (10.6ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 40 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.4ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 3 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 41 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.3ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 4 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 42 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.3ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 5 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 43 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.3ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 6 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 44 ORDER BY `comments`.`lft`
[active_model_serializers]   User Load (0.4ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 8 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.6ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 45 ORDER BY `comments`.`lft`
[active_model_serializers]   Team Load (0.5ms)  SELECT  `teams`.* FROM `teams` WHERE `teams`.`id` = 2 LIMIT 1
[active_model_serializers]   Action::Comment Load (0.4ms)  SELECT `comments`.* FROM `comments` WHERE `comments`.`deleted_at` IS NULL AND `comments`.`parent_id` = 61 ORDER BY `comments`.`lft`
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 2 LIMIT 1  [["id", 2], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 1 LIMIT 1  [["id", 1], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 2 LIMIT 1  [["id", 2], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 3 LIMIT 1  [["id", 3], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.2ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 4 LIMIT 1  [["id", 4], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 5 LIMIT 1  [["id", 5], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 6 LIMIT 1  [["id", 6], ["LIMIT", 1]]
[active_model_serializers]   CACHE (5.6ms)  SELECT  `users`.* FROM `users` WHERE `users`.`deleted_at` IS NULL AND `users`.`id` = 8 LIMIT 1  [["id", 8], ["LIMIT", 1]]
[active_model_serializers]   CACHE (0.0ms)  SELECT  `teams`.* FROM `teams` WHERE `teams`.`id` = 2 LIMIT 1  [["id", 2], ["LIMIT", 1]]
[active_model_serializers] Rendered ActiveModel::Serializer::CollectionSerializer with ActiveModelSerializers::Adapter::Attributes (95.65ms)

在111ms完成200 OK（浏览次数：70.3ms | ActiveRecord：34.8ms）

这实际上是总共10条评论的输出

preload /包含Serializer的多态关联

问题：

0 个答案: