[rabbitmq-discuss] Unofficial guide to AMQP 1.0 PR3

Mon May 10 15:35:17 BST 2010

On 05/07/2010 03:59 PM, Jason Pellerin wrote:
>> Flow control acts like a more fine-grained channel.flow for publishers,
>> >  and like basic.qos for consumers; in each case, the receiving side
>> >  issues*credit*, which the sending side uses up by transferring
>> >  messages.  To do something like a basic.get, a consumer issues a single
>> >  unit of*credit*, and waits for the single message to come in.
>>      
> I hope I'm missing something, but this description jumped out at me as looking
> like AMQP 1.0 is going to include one of (IMO) 0-10's biggest mistakes.
>
> As someone using messaging mainly in web applications, basic.get is the best
> thing in amqp. When response time matters, having a single command that polls
> for a message and returns immediately if one isn't present is incredibly
> useful. Replacing that with 2+ commands and replacing polling with waiting --
> ouch.
>    

Having a poll is just a matter of setting the properties. For example Qpid
supports a 'get()' opperation with AMQP 0-10. I have not worked through the
options in detail in 1-0, but it takes this one step further with not 
only allowing a get(),
but you can even do a get() in a single stateless call i.e. (open get() 
close) in
a single command sequence.

This is particularly usefull for web-apps for example and better than any
previous version as no connection state needs to kept open as with all 
previous
versions.

Carl.
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