CREATE OR REPLACE FUNCTION message_store.id(
stream_name varchar
) RETURNS varchar AS $$ DECLARE
_id_separator_position integer;
BEGIN
_id_separator_position := STRPOS(id.stream_name, '-'); IF _id_separator_position = 0 THEN RETURN NULL; END IF; RETURN SUBSTRING(id.stream_name, _id_separator_position + 1);
END; $$ LANGUAGE plpgsql IMMUTABLE;