Swap FK ci_builds to projects for LFK

Swaps FK for ci_builds.project_id to projects

Changelog: changed

db/post_migrate/20220126210021_remove_projects_ci_builds_project_id_fk.rb

+# frozen_string_literal: true
+
+class RemoveProjectsCiBuildsProjectIdFk < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  def up
+    return if Gitlab.com? # unsafe migration, skip on GitLab.com due to https://gitlab.com/groups/gitlab-org/-/epics/7249#note_819625526
+    return unless foreign_key_exists?(:ci_builds, :projects, name: "fk_befce0568a")
+
+    with_lock_retries do
+      execute('LOCK projects, ci_builds IN ACCESS EXCLUSIVE MODE') if transaction_open?
+
+      remove_foreign_key_if_exists(:ci_builds, :projects, name: "fk_befce0568a")
+    end
+  end
+
+  def down
+    add_concurrent_foreign_key(:ci_builds, :projects, name: "fk_befce0568a", column: :project_id, target_column: :id, on_delete: :cascade)
+  end
+end

db/schema_migrations/20220126210021

+fd7940bb6f077c91d7f9928f574443ba4bf33bb90cb702c0a2ecad14398ab1cc
\ No newline at end of file

db/structure.sql

@@ -29753,9 +29753,6 @@ ALTER TABLE ONLY ci_sources_pipelines
 ALTER TABLE ONLY packages_maven_metadata
     ADD CONSTRAINT fk_be88aed360 FOREIGN KEY (package_id) REFERENCES packages_packages(id) ON DELETE CASCADE;
 
-ALTER TABLE ONLY ci_builds
-    ADD CONSTRAINT fk_befce0568a FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE CASCADE;
-
 ALTER TABLE ONLY design_management_versions
     ADD CONSTRAINT fk_c1440b4896 FOREIGN KEY (author_id) REFERENCES users(id) ON DELETE SET NULL;
 

lib/gitlab/database/gitlab_loose_foreign_keys.yml

@@ -88,6 +88,9 @@ ci_builds:
   - table: users
     column: user_id
     on_delete: async_nullify
+  - table: projects
+    column: project_id
+    on_delete: async_delete
 ci_pipelines:
   - table: merge_requests
     column: merge_request_id

spec/lib/gitlab/database/no_cross_db_foreign_keys_spec.rb

@@ -12,7 +12,6 @@ RSpec.describe 'cross-database foreign keys' do
   let(:allowed_cross_database_foreign_keys) do
     %w(
       ci_build_report_results.project_id
-      ci_builds.project_id
       ci_daily_build_group_report_results.group_id
       ci_daily_build_group_report_results.project_id
       ci_freeze_periods.project_id

spec/models/commit_status_spec.rb

@@ -987,4 +987,11 @@ RSpec.describe CommitStatus do
       commit_status.expire_etag_cache!
     end
   end
+
+  context 'loose foreign key on ci_builds.project_id' do
+    it_behaves_like 'cleanup by a loose foreign key' do
+      let!(:parent) { create(:project) }
+      let!(:model) { create(:ci_build, project: parent) }
+    end
+  end
 end