[rabbitmq-discuss] Acked Message getting redelivered

[Iain Hull]

>It sounds like you find losing messages slightly acceptable (certainly 
>better than getting dups) and are thus only using acks because you are 
>using QoS. Is that right?
Yes in this case I would prefer to drop some (very small amount of)
messages
instead of getting dups.

>If so then the simple thing to do would be to just ignore (after
acking) 
>any messages which have the "redelivered" flag set.
This could work but we would have to reduce the channel prefetch down to
1, to ensure that each channel only lost one message when a connection
dies.  

Currently the channel's prefetch is 50 with a maybe 50 queues (each of
these are merged down to a single in memory queue - one per rabbitmq
host and one per tenant).  This queue could contain hundreds of
messages.  I would not like to lose all these messages when a connection
drops, One or two messages near the head would be ok however.
 
Regards,
Iain.