[bunny-amqp-devel] using bunny with qos

[vishnu]

Hi Chris

   I was just re-reading the section on QOS http://bunnyamqp.wordpress.com/2009/09/20/bunny-quality-of-service-or-prefetch/

and how it's needed if subscribers subscribing in ack mode need to use qos if they are likely to call other methods on bunny.

I had a couple of questions though. I realise I didn't quite follow somethings there.

The first is about prefetch count. If I use qos with a prefetch count greater than 1, won't I have the same problem that your example raised? Or is it a matter of picking up a small enough prefetch count that all these messages are recieved by bunny before the subscribe block executes?

The other question was if qos is required if a subscribe block is going to perform a publish? Is there a publish ok message that the server sends back?

thanks

Vishnu

[Chris Duncan (Frugal IT)]

Hi Vishnu.

On 17 Mar 2010, at 05:25, vishnu wrote:

Hi Chris

   I was just re-reading the section on QOS http://bunnyamqp.wordpress.com/2009/09/20/bunny-quality-of-service-or-prefetch/

and how it's needed if subscribers subscribing in ack mode need to use qos if they are likely to call other methods on bunny.

I had a couple of questions though. I realise I didn't quite follow somethings there.

The first is about prefetch count. If I use qos with a prefetch count greater than 1, won't I have the same problem that your example raised? Or is it a matter of picking up a small enough prefetch count that all these messages are recieved by bunny before the subscribe block executes?

If you are not making any synchronous AMQP calls in the block then everything should work with a prefetch count greater than 1. AMQP method calls that return a message are the things that give you a problem because the reply message from the block gets mixed up with the other messages that you are consuming.

The other question was if qos is required if a subscribe block is going to perform a publish? Is there a publish ok message that the server sends back?

Publishing from the block should be OK because it is an asynchronous AMQP method according to the AMQP spec and therefore there is no publish_ok reply message.

thanks

Vishnu

Regards,

Chris

[vishnu]

aha thanks