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From Tim Chen <...@evri.com>
Subject Re: regarding Last value queue
Date Fri, 06 Aug 2010 23:19:02 GMT
Hi Robert,

So I do have a consumer waiting for it, and it's not picking up  
anything (consumer.receive(1000) gives null all the time).

I want to use the LVQ to provide a queue for one (maybe more?) client  
to receive messages,

and when the user is still processing the earlier messages, the  
producer side can update the items in the LVQ using keys that is not  
yet processed but has newer content available.

Hopefully this makes sense.

Anyhow, currently the queue doesn't seem to receive anything since  
both consumer and JMX shows nothing coming in or out of it.

Please let me know is there something wrong in my setup.

Thanks!

Tim



On Aug 6, 2010, at 2:59 PM, Robert Godfrey wrote:

> On 6 August 2010 20:15, Tim Chen <tim@evri.com> wrote:
>> Hi all,
>>
>> I'm trying to play with last value queue. I see that there isn't any
>> development release for 0.7, so I grabbed trunk from git and tried  
>> to do the
>> following:
>>
>>   Map arguments = new HashMap<String, Object>();
>>                             
>> arguments.put("qpid.last_value_queue",true);
>>
>>  arguments.put("qpid.last_value_queue_key","LVQ.key");
>>
>>                        AMQShortString name = new  
>> AMQShortString(_queueName);
>>                        session.createQueue( name, true, true, false,
>> arguments );
>>
>> To create the LVQ. And if I don't set the key on the messages, it  
>> seems to
>> be able to send messages correctly.
>>
>> However, once I set the key on the message:
>>
>> message.setStringProperty( "LVQ.key", key );
>>
>> Messages won't be delieverd to the queue at all, from looking at  
>> the JMX
>> console.
>>
>> I wonder how do I make it work?
>>
>> Thanks,
>>
>> Tim
>
> Hi Tim,
>
> from the above description (and mention of JMX console) I'm assuming
> you're trying to use the LVQ on the Java Broker (the C++ Broker also
> has an implementation of LVQ, but it doesn't work in quite the same
> way).
>
> From the above, and the fact that you see something "different" happen
> when you send a message with the key set, it sounds like you have set
> the queue up correctly... What are you seeing on the JMX console that
> makes you think it is not being delivered?  Do you have an consumers
> on the queue to which the messages are being sent?
>
> More generally what is your use case for the LVQ - are you wanting to
> use it as a "queue" where at most one client will see any message sent
> to it, or are you looking for more topic like behaviour (where each
> client listening to the queue will see updates)?
>
> Cheers,
> Rob
>
>>
>> ---------------------------------------------------------------------
>> Apache Qpid - AMQP Messaging Implementation
>> Project:      http://qpid.apache.org
>> Use/Interact: mailto:dev-subscribe@qpid.apache.org
>>
>>
>
> ---------------------------------------------------------------------
> Apache Qpid - AMQP Messaging Implementation
> Project:      http://qpid.apache.org
> Use/Interact: mailto:dev-subscribe@qpid.apache.org
>


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