modqueue: optimize sql queries.

* Include appeals and flags.
* Avoid an existence query for pools.
* Avoid a query checking if the user has previously approved the post.
  This is a rare condition and it will be prevented anyway if the user
  tries to reapprove the post.

app/controllers/moderator/post/queues_controller.rb

@@ -10,10 +10,7 @@ module Moderator
           cookies.permanent["mq_per_page"] = search_params[:per_page]
         end
 
-        ::Post.without_timeout do
+        @posts = ::Post.includes(:appeals, :disapprovals, :uploader, flags: [:creator]).reorder(id: :asc).pending_or_flagged.available_for_moderation(search_params[:hidden]).tag_match(search_params[:tags]).paginate(params[:page], :limit => per_page)
-          @posts = ::Post.includes(:disapprovals, :uploader).order("posts.id asc").pending_or_flagged.available_for_moderation(search_params[:hidden]).tag_match(search_params[:tags]).paginate(params[:page], :limit => per_page)
-          @posts.each # hack to force rails to eager load
-        end
         respond_with(@posts)
       end
 

app/models/post.rb

@@ -273,7 +273,7 @@ class Post < ApplicationRecord
 
   module ApprovalMethods
     def is_approvable?(user = CurrentUser.user)
-      !is_status_locked? && (is_pending? || is_flagged? || is_deleted?) && uploader != user && !approved_by?(user)
+      !is_status_locked? && (is_pending? || is_flagged? || is_deleted?) && uploader != user
     end
 
     def flag!(reason, is_deletion: false)
@@ -288,10 +288,6 @@ class Post < ApplicationRecord
       approvals.create(user: approver)
     end
 
-    def approved_by?(user)
-      approver == user || approvals.where(user: user).exists?
-    end
-
     def disapproved_by?(user)
       PostDisapproval.where(:user_id => user.id, :post_id => id).exists?
     end
@@ -989,7 +985,7 @@ class Post < ApplicationRecord
     end
 
     def has_active_pools?
-      !pools.undeleted.empty?
+      pools.undeleted.present?
     end
 
     def belongs_to_pool?(pool)

app/models/post_approval.rb

@@ -20,7 +20,7 @@ class PostApproval < ApplicationRecord
       errors.add(:base, "You cannot approve a post you uploaded")
     end
 
-    if post.approved_by?(user)
+    if post.approver == user || post.approvals.where(user: user).exists?
       errors.add(:base, "You have previously approved this post and cannot approve it again")
     end
   end

test/unit/post_approval_test.rb

@@ -22,10 +22,6 @@ class PostApprovalTest < ActiveSupport::TestCase
       CurrentUser.ip_addr = nil
     end
 
-    should "allow approval" do
-      assert_equal(false, @post.approved_by?(@approver))
-    end
-
     context "That is approved" do
       should "create a postapproval record" do
         assert_difference("PostApproval.count") do