[rabbitmq-discuss] Question on Rabbit's Message Copying

Tue Dec 4 15:34:44 GMT 2012

Thanks Tony,
That helped my understanding.

On Tue, Dec 4, 2012 at 9:50 AM, Tony Garnock-Jones <
tonygarnockjones+rabbitmq at gmail.com> wrote:

> Hi Ashwin,
>
> Messages are not explicitly copied - Erlang's message-passing is used to
> distribute "copies" of each AMQP message to the queue processes it is
> destined for. Since Erlang terms are immutable, the underlying
> memory-management system is free to use whichever strategy works best.
> Sometimes that will be many pointers to a shared value; other times it will
> be separate copies. I don't know which strategy Erlang chooses at present:
> you will have to ask the Erlang mailing list or do some experiments of your
> own. Hope this helps!
>
> Regards,
>   Tony
>
>
> On 4 December 2012 01:40, Ashwin Raghav <ashwinraghav at gmail.com> wrote:
>
>> Hi tony,
>> I had a questions about how(whether) rabbit internally copies a message
>> from an exchange to a queue.
>> I have read the documentation that says "Exchanges copy messages to
>> queues using rules called bindings".
>>
>> I was wondering whether this is a logical copy or an actual full-on copy.
>> I ask because I was posed with a question recently on a project that I work
>> on. Why are you physically copying the same message to so many queues?
>> Would something like a reference count implementation with just a single
>> copy of the message not suffice?
>>
>> Kindly clarify.
>> --
>> Regards,
>> Ashwin Raghav Mohan Ganesh
>>
>> --
>> Tony Garnock-Jones
>> tonygarnockjones at gmail.com
>> http://homepages.kcbbs.gen.nz/tonyg/
>>
>>

-- 
Regards,
Ashwin Raghav Mohan Ganesh
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