On 1 May 2006, at 11:22, reza aliakbary wrote:

> Hello,
>
>   Suppose this scenario: I have 10 queues in my application and I  
> want to  consume their messages asynchronously. I want to know whether
>
>   1- it can slow down the server if I add alot of consumers to  
> this  queues (event if they are idle) or not(For example 50 for  
> each  queue).
There's always some overhead with adding more consumers - but it's  
usually negligible.  BTW you mean a queue consumer per Connection   
right?
  For connections, the overhead is an additional file descriptor, and  
depending on your operating system, these are usually limited on a  
per-process basis (free BSD is 1024), Linux (256) etc - though if  
your an admin you can change these; and depending on the transport,  
an additional thread.

>
>   2- What is your suggestion for adding consumers to the queues.  
> Should I  add consumers at start of application and leave them to  
> consume  messages or I should manage them during the life time of  
> application,  for example removing idle consumers from the queues  
> that are not busy  for a long time and adding consumers to the  
> queues that are busy.

Good question!  - and really dependent on your architecture and  
'weight' of consumers.
Usually it's good practice to have a few active consumers, and  
monitor the depth of the Queue using JMX. You could raise JMX  
notifications if the depth of a Queue exceeds a set limit and spawn  
up another consumer or two, and remove consumers when there is less  
load on the Queue.
>
>   Best Regards,
>   Reza
>
> 		
> ---------------------------------
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hope that helps,

cheers,

Rob

http://rajdavies.blogspot.com/