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| techno |
 Posted: Fri Jan 07, 2005 7:50 pm Post subject: publish without any subscriber |
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Chevalier
Joined: 22 Jan 2003
Posts: 429
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What would happen to the message published on a topic, when there is no subscriber subscribed to it. Does that message get removed immediately?
Thanks |
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| jefflowrey |
| Posted: Sat Jan 08, 2005 5:34 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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If there are no current or durable subscribers to a topic, I believe the message is discarded.
What should get done with it, otherwise?
_________________
I am *not* the model of the modern major general. |
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| techno |
| Posted: Sat Jan 08, 2005 6:50 am Post subject: |
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Chevalier
Joined: 22 Jan 2003
Posts: 429
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How do we synchronize first time, so that we do not loose any messages?
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| jefflowrey |
| Posted: Sat Jan 08, 2005 12:49 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Don't start the publisher until you have registered subscribers.
You don't have to have the subscribers RUNNING, just registered.
_________________
I am *not* the model of the modern major general. |
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| JLRowe |
| Posted: Sun Jan 09, 2005 2:09 pm Post subject: |
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Yatiri
Joined: 25 May 2002
Posts: 664
Location: South East London
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| You can specify that a publication is retained, the broker keeps the last publication on the topic, clients can then subscribe and receive the last publication or they can grab the last publication whenever they need it. |
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| techno |
| Posted: Sun Jan 09, 2005 4:07 pm Post subject: |
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Chevalier
Joined: 22 Jan 2003
Posts: 429
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Could you let me know how to specify/code it?
Thanks |
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| JLRowe |
| Posted: Mon Jan 10, 2005 5:25 am Post subject: |
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Yatiri
Joined: 25 May 2002
Posts: 664
Location: South East London
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Check out this explanation:
http://publib.boulder.ibm.com/infocenter/wbihelp/index.jsp?topic=/com.ibm.etools.mft.doc/aq13030_.htm
A good analogy is if you imagine a football match, if the score is published on a retained topic then clients can subscribe half way through the match and get the latest score, of course if a goal is scored then a new publication occurs and all subscribers get the new score message immediately.
I believe this feature is not available with the MQ pub/sub, only with message broker. |
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| techno |
| Posted: Mon Jan 10, 2005 9:38 am Post subject: |
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Chevalier
Joined: 22 Jan 2003
Posts: 429
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I am using MQ's Pub/Sub support pac (ma0c).
Where are the topic registrations stored? Which Queue? I didn't see them anywhere. When I used DumpBroker.class utility, I don't get old topics... I am not clear on how and what is happening. I guess I am not seeing them when there are no pending messages in JMS.D queue (susbscriber queue)
This is what I have observed:
Did susbscribe to t1:
Did publish on t1
Reecievd all the emssages. Did dump broker:
I can see t1 in the topic list.
Did susbscribe to t2:
Did publish on t2
Reecievd all the emssages. Did dump broker:
I can see only t2 in the topic list. I lost t1
When I have any pending messages to be subscribed on t1, I can see both t1 and t2.
Pls help in understanding above stuff.
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| techno |
| Posted: Wed Jan 12, 2005 10:27 pm Post subject: |
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Chevalier
Joined: 22 Jan 2003
Posts: 429
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could somebody answer above questions.
thanks |
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