FROM backlog
JOIN sender ON backlog.senderid = sender.senderid
WHERE bufferid = :bufferid
-AND backlog.messageid <= (SELECT buffer.lastmsgid FROM buffer WHERE buffer.bufferid = :bufferid)
+AND backlog.messageid <= (SELECT buffer.lastmsgid FROM buffer WHERE buffer.bufferid = :bufferidDup1)
ORDER BY messageid DESC
LIMIT :limit