Swap FK ci_pipelines to projects for LFK

Swaps FK for ci_pipelines.project_id to projects

Changelog: changed

db/post_migrate/20220126210657_remove_projects_ci_pipelines_project_id_fk.rb

+# frozen_string_literal: true
+
+class RemoveProjectsCiPipelinesProjectIdFk < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  def up
+    return unless foreign_key_exists?(:ci_pipelines, :projects, name: "fk_86635dbd80")
+
+    with_lock_retries do
+      execute('LOCK projects, ci_pipelines IN ACCESS EXCLUSIVE MODE') if transaction_open?
+
+      remove_foreign_key_if_exists(:ci_pipelines, :projects, name: "fk_86635dbd80")
+    end
+  end
+
+  def down
+    add_concurrent_foreign_key(:ci_pipelines, :projects, name: "fk_86635dbd80", column: :project_id, target_column: :id, on_delete: :cascade)
+  end
+end

db/schema_migrations/20220126210657

+853209f3babe2856481591790d9bb67145c4c0c919ed4d8365bb8d498e4f6b8e
\ No newline at end of file

db/structure.sql

@@ -29544,9 +29544,6 @@ ALTER TABLE ONLY merge_request_diffs
 ALTER TABLE ONLY requirements
     ADD CONSTRAINT fk_85044baef0 FOREIGN KEY (issue_id) REFERENCES issues(id) ON DELETE CASCADE;
 
-ALTER TABLE ONLY ci_pipelines
-    ADD CONSTRAINT fk_86635dbd80 FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
-
 ALTER TABLE ONLY geo_event_log
     ADD CONSTRAINT fk_86c84214ec FOREIGN KEY (repository_renamed_event_id) REFERENCES geo_repository_renamed_events(id) ON DELETE CASCADE;
 

lib/gitlab/database/gitlab_loose_foreign_keys.yml

@@ -112,6 +112,9 @@ ci_pipelines:
   - table: users
     column: user_id
     on_delete: async_nullify
+  - table: projects
+    column: project_id
+    on_delete: async_delete
 ci_project_mirrors:
   - table: projects
     column: project_id

spec/lib/gitlab/database/no_cross_db_foreign_keys_spec.rb

@@ -19,7 +19,6 @@ RSpec.describe 'cross-database foreign keys' do
       ci_pending_builds.namespace_id
       ci_pending_builds.project_id
       ci_pipeline_schedules.owner_id
-      ci_pipelines.project_id
       ci_resource_groups.project_id
       ci_runner_namespaces.namespace_id
       ci_running_builds.project_id

spec/models/ci/pipeline_spec.rb

@@ -4731,4 +4731,11 @@ RSpec.describe Ci::Pipeline, :mailer, factory_default: :keep do
       let!(:model) { create(:ci_pipeline, merge_request: parent) }
     end
   end
+
+  context 'loose foreign key on ci_pipelines.project_id' do
+    it_behaves_like 'cleanup by a loose foreign key' do
+      let!(:parent) { create(:project) }
+      let!(:model) { create(:ci_pipeline, project: parent) }
+    end
+  end
 end