Preload job_artifacts_archives for API endpoint

In order to prevent n+1 queries

app/models/ci/processable.rb

@@ -165,7 +165,13 @@ module Ci
     end
 
     def all_dependencies
-      dependencies.all
+      if Feature.enabled?(:preload_associations_jobs_request_api_endpoint, project, default_enabled: :yaml)
+        strong_memoize(:all_dependencies) do
+          dependencies.all
+        end
+      else
+        dependencies.all
+      end
     end
 
     private

app/presenters/ci/build_runner_presenter.rb

@@ -55,6 +55,18 @@ module Ci
       specs
     end
 
+    # rubocop: disable CodeReuse/ActiveRecord
+    def all_dependencies
+      dependencies = super
+
+      if Feature.enabled?(:preload_associations_jobs_request_api_endpoint, project, default_enabled: :yaml)
+        ActiveRecord::Associations::Preloader.new.preload(dependencies, :job_artifacts_archive)
+      end
+
+      dependencies
+    end
+    # rubocop: enable CodeReuse/ActiveRecord
+
     private
 
     def create_archive(artifacts)

config/feature_flags/development/preload_associations_jobs_request_api_endpoint.yml

+---
+name: preload_associations_jobs_request_api_endpoint
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/57694
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/326477
+milestone: "13.11"
+type: development
+group: group::continuous integration
+default_enabled: true

spec/requests/api/ci/runner/jobs_request_post_spec.rb

@@ -490,6 +490,36 @@ RSpec.describe API::Ci::Runner, :clean_gitlab_redis_shared_state do
                 { 'id' => job.id, 'name' => job.name, 'token' => job.token },
                 { 'id' => job2.id, 'name' => job2.name, 'token' => job2.token })
             end
+
+            describe 'preloading job_artifacts_archive' do
+              context 'when the feature flag is disabled' do
+                before do
+                  stub_feature_flags(preload_associations_jobs_request_api_endpoint: false)
+                end
+
+                it 'queries the ci_job_artifacts table multiple times' do
+                  expect { request_job }.to exceed_all_query_limit(1).for_model(::Ci::JobArtifact)
+                end
+
+                it 'queries the ci_builds table more than five times' do
+                  expect { request_job }.to exceed_all_query_limit(5).for_model(::Ci::Build)
+                end
+              end
+
+              context 'when the feature flag is enabled' do
+                before do
+                  stub_feature_flags(preload_associations_jobs_request_api_endpoint: true)
+                end
+
+                it 'queries the ci_job_artifacts table once only' do
+                  expect { request_job }.not_to exceed_all_query_limit(1).for_model(::Ci::JobArtifact)
+                end
+
+                it 'queries the ci_builds table five times' do
+                  expect { request_job }.not_to exceed_all_query_limit(5).for_model(::Ci::Build)
+                end
+              end
+            end
           end
 
           context 'when pipeline have jobs with artifacts' do

spec/support/matchers/exceed_query_limit.rb

@@ -20,6 +20,11 @@ module ExceedQueryLimitHelpers
     self
   end
 
+  def for_model(model)
+    table = model.table_name if model < ActiveRecord::Base
+    for_query(/(FROM|UPDATE|INSERT INTO|DELETE FROM)\s+"#{table}"/)
+  end
+
   def show_common_queries
     @show_common_queries = true
     self

spec/support_specs/matchers/exceed_query_limit_helpers_spec.rb

@@ -225,6 +225,16 @@ RSpec.describe ExceedQueryLimitHelpers do
     expect(test_matcher.actual_count).to eq(2)
   end
 
+  it 'can filter specific models' do
+    test_matcher = TestMatcher.new.for_model(TestQueries)
+    test_matcher.verify_count do
+      TestQueries.first
+      TestQueries.connection.execute('select 1')
+    end
+
+    expect(test_matcher.actual_count).to eq(1)
+  end
+
   it 'can ignore specific queries' do
     test_matcher = TestMatcher.new.ignoring(/foobar/)
     test_matcher.verify_count do