in Sqlalchemy, the expired messages are not be removed automatically, see https://bugs.launchpad.net/marconi/+bug/1331228
and they are be removed automatically, we still need to filter them out explicitly since there will a time-window
in Sqlalchemy, the expired messages are not be removed automatically, see https:/ /bugs.launchpad .net/marconi/ +bug/1331228
and they are be removed automatically, we still need to filter them out explicitly since there will a time-window