PERF: prevents N+1 on last_updated_by (#32817)

plugins/automation/app/controllers/discourse_automation/admin_automations_controller.rb

@@ -8,7 +8,7 @@ module DiscourseAutomation
       automations =
         DiscourseAutomation::Automation
           .strict_loading
-          .includes(:fields, :pending_automations)
+          .includes(:fields, :pending_automations, :last_updated_by)
           .order(:name)
           .limit(500)
           .all
@@ -26,7 +26,11 @@ module DiscourseAutomation
 
     def show
       automation =
-        DiscourseAutomation::Automation.includes(:fields, :pending_automations).find(params[:id])
+        DiscourseAutomation::Automation.includes(
+          :fields,
+          :pending_automations,
+          :last_updated_by,
+        ).find(params[:id])
       render_serialized_automation(automation)
     end
 

plugins/automation/app/models/discourse_automation/automation.rb

@@ -4,6 +4,8 @@ module DiscourseAutomation
   class Automation < ActiveRecord::Base
     self.table_name = "discourse_automation_automations"
 
+    belongs_to :last_updated_by, class_name: "User", foreign_key: "last_updated_by_id"
+
     has_many :fields,
              class_name: "DiscourseAutomation::Field",
              dependent: :delete_all,
@@ -17,7 +19,6 @@ module DiscourseAutomation
              class_name: "DiscourseAutomation::PendingPm",
              dependent: :delete_all,
              foreign_key: "automation_id"
-
     has_many :stats, class_name: "DiscourseAutomation::Stat", dependent: :delete_all
 
     validates :script, presence: true

plugins/automation/app/serializers/discourse_automation/automation_serializer.rb

@@ -14,10 +14,7 @@ module DiscourseAutomation
     attribute :stats
 
     def last_updated_by
-      BasicUserSerializer.new(
-        User.find_by(id: object.last_updated_by_id) || Discourse.system_user,
-        root: false,
-      ).as_json
+      BasicUserSerializer.new(object.last_updated_by || Discourse.system_user, root: false).as_json
     end
 
     def include_next_pending_automation_at?