Function getRelationIdentity

src/backend/catalog/objectaddress.c:6453–6482

* Append the relation identity (quoted qualified name) to the given * StringInfo. */

 * StringInfo.
 */
static void
getRelationIdentity(StringInfo buffer, Oid relid, List **object,
					bool missing_ok)
{
	HeapTuple	relTup;
	Form_pg_class relForm;
	char	   *schema;

	relTup = SearchSysCache1(RELOID,
							 ObjectIdGetDatum(relid));
	if (!HeapTupleIsValid(relTup))
	{
		if (!missing_ok)
			elog(ERROR, "cache lookup failed for relation %u", relid);

		if (object)
			*object = NIL;
		return;
	}
	relForm = (Form_pg_class) GETSTRUCT(relTup);

	schema = get_namespace_name_or_temp(relForm->relnamespace);
	appendStringInfoString(buffer,
						   quote_qualified_identifier(schema,
													  NameStr(relForm->relname)));
	if (object)
		*object = list_make2(schema, pstrdup(NameStr(relForm->relname)));

	ReleaseSysCache(relTup);
}

/*
 * Auxiliary function to build a TEXT array out of a list of C-strings.