Swap FK ci_project_monthly_usages to projects for LFK

Swaps FK for ci_project_monthly_usages.project_id to projects

Changelog: changed

db/post_migrate/20220124221521_remove_projects_ci_project_monthly_usages_project_id_fk.rb

+# frozen_string_literal: true
+
+class RemoveProjectsCiProjectMonthlyUsagesProjectIdFk < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  def up
+    return unless foreign_key_exists?(:ci_project_monthly_usages, :projects, name: "fk_rails_508bcd4aa6")
+
+    with_lock_retries do
+      execute('LOCK projects, ci_project_monthly_usages IN ACCESS EXCLUSIVE MODE') if transaction_open?
+
+      remove_foreign_key_if_exists(:ci_project_monthly_usages, :projects, name: "fk_rails_508bcd4aa6")
+    end
+  end
+
+  def down
+    add_concurrent_foreign_key(:ci_project_monthly_usages, :projects, name: "fk_rails_508bcd4aa6", column: :project_id, target_column: :id, on_delete: :cascade)
+  end
+end

db/schema_migrations/20220124221521

+4b1dad4fc34717c9b89a770e4e0682b0cee7d421da68223011bb9fde9460d1f8
\ No newline at end of file

db/structure.sql

@@ -30497,9 +30497,6 @@ ALTER TABLE ONLY resource_iteration_events
 ALTER TABLE ONLY status_page_settings
     ADD CONSTRAINT fk_rails_506e5ba391 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
 
-ALTER TABLE ONLY ci_project_monthly_usages
-    ADD CONSTRAINT fk_rails_508bcd4aa6 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
-
 ALTER TABLE ONLY project_repository_storage_moves
     ADD CONSTRAINT fk_rails_5106dbd44a FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
 

ee/app/graphql/types/ci/minutes/project_monthly_usage_type.rb

@@ -16,7 +16,7 @@ module Types
               description: 'Name of the project.'
 
         def name
-          object.project.name
+          object.project&.name
         end
       end
     end

ee/app/services/ci/minutes/update_project_and_namespace_usage_service.rb

@@ -96,8 +96,9 @@ module Ci
 
       def project_usage
         strong_memoize(:project_usage) do
-          ::Ci::Minutes::ProjectMonthlyUsage.find_or_create_current(project_id: @project_id)
-        rescue ActiveRecord::InvalidForeignKey
+          if @project.present?
+            ::Ci::Minutes::ProjectMonthlyUsage.find_or_create_current(project_id: @project_id)
+          end
         end
       end
 

ee/spec/models/ci/minutes/project_monthly_usage_spec.rb

@@ -111,4 +111,11 @@ RSpec.describe Ci::Minutes::ProjectMonthlyUsage do
       it_behaves_like 'namespace monthly usage'
     end
   end
+
+  context 'loose foreign key on ci_project_monthly_usages.project_id' do
+    it_behaves_like 'cleanup by a loose foreign key' do
+      let!(:parent) { create(:project) }
+      let!(:model) { create(:ci_project_monthly_usage, project: parent) }
+    end
+  end
 end

lib/gitlab/database/gitlab_loose_foreign_keys.yml

@@ -128,6 +128,10 @@ packages_package_file_build_infos:
   - table: ci_pipelines
     column: pipeline_id
     on_delete: async_nullify
+ci_project_monthly_usages:
+  - table: projects
+    column: project_id
+    on_delete: async_delete
 pages_deployments:
   - table: ci_builds
     column: ci_build_id

spec/lib/gitlab/database/no_cross_db_foreign_keys_spec.rb

@@ -25,7 +25,6 @@ RSpec.describe 'cross-database foreign keys' do
       ci_pipeline_schedules.owner_id
       ci_pipeline_schedules.project_id
       ci_pipelines.project_id
-      ci_project_monthly_usages.project_id
       ci_resource_groups.project_id
       ci_runner_namespaces.namespace_id
       ci_runner_projects.project_id