Ruby on rails 为序列化程序预加载/包含多态关联

所有者可以是

团队

或

用户

或

组

。它们中的每一个都具有在

问题是： 我们确实使用

ActiveModel:：Serializer

作为我们的响应。（

CommentSerializer

）。在我们定义的序列化程序中，

属于：owner

，并且

有很多：children

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

这很好，但考虑到100条评论（其中大多数都有孩子的评论），它的表现还远远不够好。因此，我们可以轻松查找300多个用户/团队/组关联

我们如何预加载它们？我在想类似的事情

car.comments.include（：children，：owner）

但是对于变形关联来说这是如何工作的呢

render json: car.comments

在111ms内完成200 OK（视图：70.3ms |活动记录：34.8ms）

这实际上是总共10条注释的输出

[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)