Optimize issue search when sorting by due date and position

When searching for issues within a project or group, `IssuableFinder`
has an optimization that uses a CTE to filter the list of authorized
issues before searching within the list for text. This CTE optimization
fence is currently only used when the user specifies a simple sorting
parameter, such as `created_at`, and not popularity. These attributes
are generally stored directly with the model, so the CTE can easily do
an `ORDER BY` without joining another table (e.g. `award_emoji` for
popularity).

This commit adds the remaining simple sort attributes (due date,
relative position) the `Issue` class. This should help speed up the
search query and avoid a database statement timeout.

Improves https://gitlab.com/gitlab-org/gitlab/issues/34661

app/models/issue.rb

@@ -147,6 +147,20 @@ class Issue < ApplicationRecord
     'project_id'
   end
 
+  def self.simple_sorts
+    super.merge(
+      {
+        'closest_future_date' => -> { order_closest_future_date },
+        'closest_future_date_asc' => -> { order_closest_future_date },
+        'due_date' => -> { order_due_date_asc.with_order_id_desc },
+        'due_date_asc' => -> { order_due_date_asc.with_order_id_desc },
+        'due_date_desc' => -> { order_due_date_desc.with_order_id_desc },
+        'relative_position' => -> { order_relative_position_asc.with_order_id_desc },
+        'relative_position_asc' => -> { order_relative_position_asc.with_order_id_desc }
+      }
+    )
+  end
+
   def self.sort_by_attribute(method, excluded_labels: [])
     case method.to_s
     when 'closest_future_date', 'closest_future_date_asc' then order_closest_future_date

changelogs/unreleased/sh-add-due-date-simple-sort.yml

+---
+title: Optimize issue search when sorting by due date and position
+merge_request: 24217
+author:
+type: performance

ee/spec/models/issue_spec.rb

@@ -214,7 +214,9 @@ describe Issue do
     it 'includes weight with other base keys' do
       expect(Issue.simple_sorts.keys).to match_array(
         %w(created_asc created_at_asc created_date created_desc created_at_desc
-           id_asc id_desc updated_desc updated_asc updated_at_asc updated_at_desc
+           closest_future_date closest_future_date_asc due_date due_date_asc due_date_desc
+           id_asc id_desc relative_position relative_position_asc
+           updated_desc updated_asc updated_at_asc updated_at_desc
            weight weight_asc weight_desc))
     end
   end

spec/models/issue_spec.rb

@@ -84,6 +84,16 @@ describe Issue do
     end
   end
 
+  describe '.simple_sorts' do
+    it 'includes all keys' do
+      expect(described_class.simple_sorts.keys).to include(
+        *%w(created_asc created_at_asc created_date created_desc created_at_desc
+            closest_future_date closest_future_date_asc due_date due_date_asc due_date_desc
+            id_asc id_desc relative_position relative_position_asc
+            updated_desc updated_asc updated_at_asc updated_at_desc))
+    end
+  end
+
   describe '#order_by_position_and_priority' do
     let(:project) { create :project }
     let(:p1) { create(:label, title: 'P1', project: project, priority: 1) }