create unique index metadata_authority_type_url on metadata_authority(type, url);
--- origin_metadata
-create unique index concurrently origin_metadata_pkey on origin_metadata(id);
-alter table origin_metadata add primary key using index origin_metadata_pkey;
+-- object_metadata
+create unique index concurrently object_metadata_content_authority_date_fetcher on object_metadata(id, authority_id, discovery_date, fetcher_id);
-create unique index concurrently origin_metadata_origin_authority_date_fetcher on origin_metadata(origin_id, authority_id, discovery_date, fetcher_id);