为什么Ransack在每个循环中执行查询

Question

我与所有成员一起搜索特殊组：

控制器：

class Groups::MembersController < ApplicationController
  def index
    @group = Group.find_by_name(params[:groupname])
    @search = @group.members.ransack(params[:q])
    @members = @search.result().includes(:user).page(params[:page]).per(5)
    respond_to do |format|
      format.js
      format.html
    end
  end
  ...

模型：

class Member < ApplicationRecord
  belongs_to :user
  belongs_to :group
end

查看：在这里存放。

...
- puts 'Out'
- @members.each do |member|
  - puts 'In'
  - user = member.user
  - userShow = user_path(user)
  .list-group-item{id: member.id}
  ...

输出：

Started GET "/groups/Test/members" for 127.0.0.1 at
Processing by Groups::MembersController#index as HTML
  Parameters: {"groupname"=>"Test"}
  Group Load (0.0ms)  SELECT  "groups".* FROM "groups" WHERE "groups"."name" = ? LIMIT ?  [["name", "Test"], ["LIMIT", 1]]
  Rendering groups/members/index.html.haml within layouts/application
  Rendered layouts/nav/sidebar/_groups.html.haml (4.0ms)
Out
  Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ? OFFSET ?  [["group_id", 2], ["LIMIT", 5], ["OFFSET", 0]]
  User Load (0.5ms)  SELECT "users".* FROM "users" WHERE "users"."id" IN (15, 24, 48, 9, 4)
In
  Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ?  [["group_id", 2], ["LIMIT", 11]]
In
  CACHE Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ?  [["group_id", 2], ["LIMIT", 11]]
In
  CACHE Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ?  [["group_id", 2], ["LIMIT", 11]]
In
  CACHE Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ?  [["group_id", 2], ["LIMIT", 11]]
In
  CACHE Member Load (0.0ms)  SELECT  "members".* FROM "members" WHERE "members"."group_id" = ? LIMIT ?  [["group_id", 2], ["LIMIT", 11]]
  Rendered groups/members/_index_list.html.haml (7068.8ms)
   (0.0ms)  SELECT COUNT(*) FROM "members" WHERE "members"."group_id" = ?  [["group_id", 2]]
  Rendered groups/members/index.html.haml within layouts/application (7313.5ms)
  Rendered layouts/_head.html.haml (274.7ms)
  User Load (0.5ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ?  [["id", 1], ["LIMIT", 1]]
  Rendered layouts/header/_default.html.haml (7.0ms)
  Rendered layouts/_nav.html.haml (2.0ms)
  Rendered layouts/_flash.html.haml (14.0ms)
Completed 200 OK in 7965ms (Views: 7931.9ms | ActiveRecord: 1.0ms)

我不明白为什么在每个循环中执行查询。即使使用缓存完成，也要花费我的性能。我可以修复吗？

Answer 1

我认为您误认为延迟在哪里。用一些时间戳来启动您的代码，然后发布发生的情况：

- puts "before loop: #{Time.now.to_s(:utc)}"
- puts 'Out'
- @members.each do |member|
  - puts "In loop  #{Time.now.to_s(:utc)}"
  - user = member.user
    - puts "after member.user call  #{Time.now.to_s(:utc)}"
  - userShow = user_path(user)
  .list-group-item{id: member.id}
- puts "End loop  #{Time.now.to_s(:utc)}"