-JOIN sender ON backlog.senderid = sender.senderid
-WHERE bufferid = :bufferid
- AND backlog.messageid >= :firstmsg
- AND backlog.messageid < :lastmsg
+LEFT JOIN sender ON backlog.senderid = sender.senderid
+WHERE backlog.messageid >= $1
+ AND backlog.messageid < $2
+ AND bufferid = $3