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Posted to dev@qpid.apache.org by Tim Chen <ti...@evri.com> on 2010/08/06 20:15:06 UTC
regarding Last value queue
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
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Project: http://qpid.apache.org
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Re: regarding Last value queue
Posted by Robert Godfrey <ro...@gmail.com>.
Hi Tim,
I haven't been able to reproduce your issue, with the following code I
get one message returned from the LVQ as expected - "Message 1" when
the second send is commented out, "Message 2" when the second send is
uncommented. Does this code not work for you?
public static void main(String[] args) throws Exception
{
Connection producerConnection = new AMQConnection("127.0.0.1",
5672, "guest", "guest", "producer", "/test");
AMQSession producerSession = (AMQSession)
producerConnection.createSession(false, Session.AUTO_ACKNOWLEDGE);
final Map<String,Object> arguments = new HashMap<String, Object>();
arguments.put("qpid.last_value_queue_key","LVQ.key");
producerSession.createQueue(new AMQShortString("QUEUE"),
false, true, false, arguments);
AMQQueue queue = new
org.apache.qpid.client.AMQQueue("amq.direct","QUEUE");
producerSession.declareAndBind(queue);
MessageProducer producer = producerSession.createProducer(queue);
Message msg = producerSession.createTextMessage("Message 1");
msg.setStringProperty( "LVQ.key", "test");
producer.send(msg);
// Uncomment below to test conflation is occurring
/*
msg = producerSession.createTextMessage("Message 2");
msg.setStringProperty( "LVQ.key", "test");
producer.send(msg);
*/
producer.close();
producerSession.close();
producerConnection.close();
Connection consumerConnection = new AMQConnection("127.0.0.1",
5672, "guest", "guest", "consumer", "/test");
AMQSession consumerSession = (AMQSession)
consumerConnection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageConsumer consumer = consumerSession.createConsumer(queue);
consumerConnection.start();
Message received;
while((received = consumer.receive(1000))!=null)
{
System.out.println("Message: \"" +
((TextMessage)received).getText() + "\"\t key: " +
received.getStringProperty("LVQ.key"));
}
consumer.close();
consumerSession.close();
consumerConnection.close();
}
Cheers,
Rob
On 7 August 2010 01:19, Tim Chen <ti...@evri.com> wrote:
> 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 <ti...@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
>>
>
>
---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project: http://qpid.apache.org
Use/Interact: mailto:dev-subscribe@qpid.apache.org
Re: regarding Last value queue
Posted by Tim Chen <ti...@evri.com>.
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 <ti...@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
>
---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project: http://qpid.apache.org
Use/Interact: mailto:dev-subscribe@qpid.apache.org
Re: regarding Last value queue
Posted by Robert Godfrey <ro...@gmail.com>.
On 6 August 2010 20:15, Tim Chen <ti...@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