[rabbitmq-discuss] A new exchange type

[Martin Sustrik]

Ben Hyde wrote:
> This cache of last msg of a given key exchange type is useful only if  
> the messages are
> absolute, rather than a series of diffs on the state of the thing  
> denoted by the key.  Is that
> the typical pattern in these parts?

Last value cache is typical of stock trading.

Diffs are typical of video streaming.

Thus mixing the two seems of little interest... but...

Think of FIX/FAST transferred over AMQP. FAST encoding of a stock quote 
is actually a diff. Storing it in the last value cache makes little 
sense. This is a strong argument in favor of building last value cache 
on top of AMQP, in application layer where messages are already decoded, 
rather then in AMQP that deals with raw encoded data.

Martin