FROM backlog
JOIN sender ON backlog.senderid = sender.senderid
WHERE backlog.messageid >= $1
-AND backlog.messageid <= (SELECT buffer.lastmsgid FROM buffer WHERE buffer.bufferid = $1)
+AND backlog.messageid <= (SELECT buffer.lastmsgid FROM buffer WHERE buffer.bufferid = $2)
AND bufferid = $2
ORDER BY messageid DESC
LIMIT $3