Allow old background migration that does cross-DB query

ee/lib/ee/gitlab/background_migration/migrate_security_scans.rb

@@ -9,14 +9,17 @@ module EE
 
         override :perform
         def perform(start_id, stop_id)
-          execute <<~SQL
-            INSERT INTO security_scans (created_at, updated_at, build_id, scan_type)
-            SELECT ci_job_artifacts.created_at, ci_job_artifacts.updated_at, ci_job_artifacts.job_id, ci_job_artifacts.file_type - 4
-            FROM ci_job_artifacts
-            WHERE ci_job_artifacts.id BETWEEN #{start_id} AND #{stop_id}
-            AND ci_job_artifacts.file_type BETWEEN 5 and 8
-            ON CONFLICT (build_id, scan_type) DO NOTHING;
-          SQL
+          # Introduced in GitLab 12.9, will be removed as part of https://gitlab.com/gitlab-org/gitlab/-/issues/33124
+          ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/331248') do
+            execute <<~SQL
+              INSERT INTO security_scans (created_at, updated_at, build_id, scan_type)
+              SELECT ci_job_artifacts.created_at, ci_job_artifacts.updated_at, ci_job_artifacts.job_id, ci_job_artifacts.file_type - 4
+              FROM ci_job_artifacts
+              WHERE ci_job_artifacts.id BETWEEN #{start_id} AND #{stop_id}
+              AND ci_job_artifacts.file_type BETWEEN 5 and 8
+              ON CONFLICT (build_id, scan_type) DO NOTHING;
+            SQL
+          end
         end
 
         def execute(sql)

ee/lib/ee/gitlab/background_migration/populate_vulnerability_feedback_pipeline_id.rb

@@ -38,7 +38,10 @@ module EE
               AND "vulnerability_feedback"."project_id" = "pipelines_with_reports"."project_id";
           SQL
 
-          connection.execute(update_feedback_pipeline_id_sql)
+          # Introduced in GitLab 13.6, will be removed as part of https://gitlab.com/gitlab-org/gitlab/-/issues/331248
+          ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/331248') do
+            connection.execute(update_feedback_pipeline_id_sql)
+          end
         end
 
         def pipelines_with_security_reports_subquery(project_ids)

spec/support/database/cross-join-allowlist.yml

@@ -9,11 +9,9 @@
 - "./ee/spec/finders/ee/namespaces/projects_finder_spec.rb"
 - "./ee/spec/graphql/ee/resolvers/namespace_projects_resolver_spec.rb"
 - "./ee/spec/lib/ee/gitlab/background_migration/migrate_approver_to_approval_rules_spec.rb"
-- "./ee/spec/lib/ee/gitlab/background_migration/migrate_security_scans_spec.rb"
 - "./ee/spec/lib/ee/gitlab/background_migration/populate_latest_pipeline_ids_spec.rb"
 - "./ee/spec/lib/ee/gitlab/background_migration/populate_resolved_on_default_branch_column_spec.rb"
 - "./ee/spec/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings_spec.rb"
-- "./ee/spec/lib/ee/gitlab/background_migration/populate_vulnerability_feedback_pipeline_id_spec.rb"
 - "./ee/spec/lib/ee/gitlab/usage_data_spec.rb"
 - "./ee/spec/migrations/schedule_populate_resolved_on_default_branch_column_spec.rb"
 - "./ee/spec/models/ci/build_spec.rb"