Rails：减少 ActiveStorage 查询量

Question

我有一个显示 3 种不同资源（Ablum、Samplepack 和 Demo）的索引页面，其中 2 种附有图像。我像这样通过我的控制器加载它们：

# static_controller.rb   
  @resources = []
  @resources.push(Album.all, Demo.all, Samplepack.all)

它导致很多的 SQL 查询以便加载它们。我想知道是否有最有效的加载附件的方法？如果有人可以 copy/paste 我 link 读一些书，那就太棒了！我在考虑 includes 或 joins 的东西，但我在网上找不到任何参考。

祝你有愉快的一天

编辑： 正如 Sebastian Palma 提到的，with_attached_<attachment> 是必需的（为简洁起见，非详尽日志）

 [Album.all, Demo.all, Samplepack.all]

# resulting SQL

  # Album n°1
  ActiveStorage::Attachment Load (1.8ms)   SELECT  "active_storage_attachments".* FROM "active_storage_attachments" WHERE "active_storage_attachments"."record_id" =  AND "active_storage_attachments"."record_type" =  AND "active_storage_attachments"."name" =  LIMIT   [["record_id", 82], ["record_type", "Album"], ["name", "album_artwork"], ["LIMIT", 1]]
  ActiveStorage::Blob Load (2.4ms)         SELECT  "active_storage_blobs".*       FROM "active_storage_blobs"       WHERE "active_storage_blobs"."id" =  LIMIT   [["id", 1227], ["LIMIT", 1]]
  # Ablum n°2 
  ActiveStorage::Attachment Load (0.2ms)   SELECT  "active_storage_attachments".* FROM "active_storage_attachments" WHERE "active_storage_attachments"."record_id" =  AND "active_storage_attachments"."record_type" =  AND "active_storage_attachments"."name" =  LIMIT   [["record_id", 83], ["record_type", "Album"], ["name", "album_artwork"], ["LIMIT", 1]]
  ActiveStorage::Blob Load (0.1ms)         SELECT  "active_storage_blobs".*       FROM "active_storage_blobs"       WHERE "active_storage_blobs"."id" =  LIMIT   [["id", 1228], ["LIMIT", 1]]
  # Album n°3
  ActiveStorage::Attachment Load (0.2ms)   SELECT  "active_storage_attachments".* FROM "active_storage_attachments" WHERE "active_storage_attachments"."record_id" =  AND "active_storage_attachments"."record_type" =  AND "active_storage_attachments"."name" =  LIMIT   [["record_id", 84], ["record_type", "Album"], ["name", "album_artwork"], ["LIMIT", 1]]
  ActiveStorage::Blob Load (0.2ms)         SELECT  "active_storage_blobs".*       FROM "active_storage_blobs"       WHERE "active_storage_blobs"."id" =  LIMIT   [["id", 1229], ["LIMIT", 1]]
  ...
  ... N+1 town (even N+2 ?)

使用with_attached_<attachment>:

 @resources = [
   Album.with_attached_album_artwork.all,
   Demo.all,
   Samplepack.with_attached_album_artwork.all
 ]

  # Albums
  ActiveStorage::Attachment Load (0.6ms)  SELECT "active_storage_attachments".* FROM "active_storage_attachments" WHERE "active_storage_attachments"."record_type" =  AND "active_storage_attachments"."name" =  AND "active_storage_attachments"."record_id" IN (, , , , , , , , , , , )  [["record_type", "Album"], ["name", "album_artwork"], ["record_id", 82], ["record_id", 83], ["record_id", 84], ["record_id", 85], ["record_id", 86], ["record_id", 87], ["record_id", 88], ["record_id", 89], ["record_id", 91], ["record_id", 93], ["record_id", 94], ["record_id", 95]]
  ActiveStorage::Blob Load (0.4ms)        SELECT "active_storage_blobs".*       FROM "active_storage_blobs"       WHERE "active_storage_blobs"."id" IN (, , , , , , , , , , , )  [["id", 1239], ["id", 1242], ["id", 1244], ["id", 1227], ["id", 1228], ["id", 1229], ["id", 1230], ["id", 1231], ["id", 1232], ["id", 1236], ["id", 1237], ["id", 1241]]

  # Samplepacks
  ActiveStorage::Attachment Load (0.3ms)  SELECT "active_storage_attachments".* FROM "active_storage_attachments" WHERE "active_storage_attachments"."record_type" =  AND "active_storage_attachments"."name" =  AND "active_storage_attachments"."record_id" =   [["record_type", "Samplepack"], ["name", "album_artwork"], ["record_id", 56]]
  ActiveStorage::Blob Load (0.2ms)        SELECT "active_storage_blobs".*       FROM "active_storage_blobs"       WHERE "active_storage_blobs"."id" =   [["id", 1243]]

Answer 1

根据您的情况 (has_many/has_one) 使用 with_attached_<attachment>:

To avoid N+1 queries, you can include the attached blobs in your query like so:

Gallery.where(user: Current.user).with_attached_photos

所以：

[
  Album.all,
  Demo.with_attached_images.all,
  Samplepack.with_attached_images.all
]

我认为没有必要创建一个空数组来填充它。

可能还有一个问题，因为您正在使用 all，请检查每个型号的真正需求。

Rails：减少 ActiveStorage 查询量

Rails: Reducing the amount of ActiveStorage queries

sql

performance

ruby-on-rails

rails-activestorage