Use loose foreign keys for pages_deployments

db/post_migrate/20211118130836_drop_pages_deployments_builds_fk.rb

+# frozen_string_literal: true
+
+class DropPagesDeploymentsBuildsFk < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  FK_NAME = 'fk_rails_c3a90cf29b'
+
+  def up
+    remove_foreign_key_if_exists(:pages_deployments, :ci_builds, name: FK_NAME)
+  end
+
+  def down
+    add_concurrent_foreign_key(
+      :pages_deployments,
+      :ci_builds,
+      name: FK_NAME,
+      column: :ci_build_id,
+      target_column: :id,
+      on_delete: :nullify
+    )
+  end
+end

db/schema_migrations/20211118130836

+2630b21c7134ac539a18798f2f2b99f468e171b79e30a184f7e8cdaccd11d465
\ No newline at end of file

db/structure.sql

@@ -31056,9 +31056,6 @@ ALTER TABLE ONLY packages_nuget_dependency_link_metadata
 ALTER TABLE ONLY group_deploy_keys_groups
     ADD CONSTRAINT fk_rails_c3854f19f5 FOREIGN KEY (group_deploy_key_id) REFERENCES group_deploy_keys(id) ON DELETE CASCADE;
 
-ALTER TABLE ONLY pages_deployments
-    ADD CONSTRAINT fk_rails_c3a90cf29b FOREIGN KEY (ci_build_id) REFERENCES ci_builds(id) ON DELETE SET NULL;
-
 ALTER TABLE ONLY merge_request_user_mentions
     ADD CONSTRAINT fk_rails_c440b9ea31 FOREIGN KEY (note_id) REFERENCES notes(id) ON DELETE CASCADE;
 

lib/gitlab/database/gitlab_loose_foreign_keys.yml

@@ -37,3 +37,7 @@ packages_package_file_build_infos:
   - table: ci_pipelines
     column: pipeline_id
     on_delete: async_nullify
+pages_deployments:
+  - table: ci_builds
+    column: ci_build_id
+    on_delete: async_nullify