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From "Keith Irwin" <keith.ir...@gmail.com>
Subject Re: when is a delivered message delivered?
Date Fri, 12 May 2006 01:24:16 GMT
On 5/11/06, Hiram Chirino <hiram@hiramchirino.com> wrote:
> Try setting you prefetch size down to 1, see:
> http://goopen.org/confluence/display/ACTIVEMQ/What+is+the+prefetch+limit+for

Interesting to know about.

> Or disable optimized acknowledge.  See:
> http://goopen.org/confluence/display/ACTIVEMQ/Optimized+Acknowledgement

Interesting as well.

It seems, though, that updating to the latest snaphot pretty much
solved the problem of messages somehow magically being re-sent even
after they've been delivered.  In RC2 messages seemed to get resent
even after five or ten minutes if, that is, I took down a client, then
brought it back up (closing and reopening a connection, I suppose).

Anyway, I'm very glad the SNAPSHOT fixed whatever it was. ;)

Keith

>
> On 5/10/06, Keith Irwin <keith.irwin@gmail.com> wrote:
> > Folks--
> >
> > I've got a bunch of client processes which listen on some topics, send
> > to others.  When I take one of the clients down, then start it back
> > up, I suddenly get a bunch of messages I've already seen.  Even though
> > I use durable subscriptions and persistent messages, this shouldn't be
> > so, should it?
> >
> > Details:
> >
> > For the topics listened to, I use a durable subscription, something like this:
> >
> >  ... // listening
> >
> >    String topicName = "bar";
> >    String listenerName = "foo";
> >    String clientId = "foo.bar";
> >    String subscriberName = "foo.bar";
> >
> >    this.connect = factory.createTopicConnection();
> >    this.connect.setClientID(clientId);
> >    this.session = connect.createTopicSession(false,
> >        Session.AUTO_ACKNOWLEDGE);
> >
> >    this.subscriber = session.createDurableSubscriber(this.topic,
> > subscriberName);
> >    this.subscriber.setMessageListener(this);
> >
> >    this.connect.start();
> >
> > --- // sending init
> >
> >   this.connect = factory.createTopicConnection();
> >   this.session = connect.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
> >   this.topic = (Topic)jndi.lookup(this.topicName);
> >   this.publisher = this.session.createPublisher(this.topic);
> >   this.connect.start();
> >
> > --- // sending
> >
> >    TextMessage textMessage = this.session.createTextMessage();
> >    textMessage.setText("stuff");
> >    testMessage.setStringProperty("something", "other");
> >    textMessage.setJMSPriority(Message.DEFAULT_PRIORITY);
> >    textMessage.setJMSDeliveryMode(DeliveryMode.PERSISTENT);
> >    textMessage.setJMSExpiration(TIME_TO_LIVE);
> >    this.publisher.send(textMessage);
> >
> > ---
> >
> >
> > And so on and so on. Basically, I use a client name + the topic name
> > as a "unique" client id and a unique subscriber name.
> >
> > So far so good.  All of this worked with OpenJMS as I'd expect (except
> > I had to write my own failover stuff in case openjms went down).
> >
> > When I run a test, everything works exactly as I expect it should.
> >
> > BUT, if I take out one of the components, then start it up again, that
> > component gets a bunch of messages it's already seen!
> >
> > ALSO, if I shut down activemq itself, then start it back up again, a
> > bunch of messages get, as far as I can tell, resent!
> >
> > Why is this so?  I'd expect that if all messages are delivered and I
> > take down a client component to, say, install a new version, I should
> > be able to bring it up without it getting a slew of new messages.
> >
> > Has anyone else seen this?  Perhaps a teensy little setting or api fixes this?
> >
> > Keith
> >
>
>
> --
> Regards,
> Hiram
>

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