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| gyadavil |
 Posted: Wed Mar 14, 2007 1:50 pm Post subject: How to avoid duplicate Publications |
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Acolyte
Joined: 01 Feb 2005
Posts: 62
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Hello
I am looking for a solution where I need to re publish the data but not all the subscribers for that topic should not receive it. In detail
I have Subscriber A and Subscriber B are there and they subscribed for a topic /Test/# (Same Topic)
I published 10 messages with topic as /Test/Test
Subscriber A got all of them but Subscriber B got only 1 to 5 and 10th message. He didn't receive 6,7,8 and 9th messages due to some error in the data or some other issue.
Now I want to republish the messages 6,7,8 and 9 with topic as /Test/Test.
How do I skip subscriber A to receive these as he already received them ??
Can someone help me how do I configure my system and messages to handle this ? |
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| fjb_saper |
| Posted: Wed Mar 14, 2007 2:19 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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You need something like magazine and backissue ordering...
A DB that stores all publications is a good point to start with...
Enjoy 
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| Michael Dag |
| Posted: Wed Mar 14, 2007 2:33 pm Post subject: Re: How to avoid duplicate Publications |
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Jedi Knight
Joined: 13 Jun 2002
Posts: 2607
Location: The Netherlands (Amsterdam)
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| gyadavil wrote: |
| He didn't receive 6,7,8 and 9th messages due to some error in the data or some other issue. |
he WHAT! ? !  
knowing pub/sub only in theory, isn't that what a durable publication is all about? publications are stored for new subscribers so they can get 'back issues' aswell or if the subscriber is offline the publication can be retrieved later...
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Michael
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| jefflowrey |
| Posted: Wed Mar 14, 2007 3:06 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Also, you can look at the Message Replay Server Support Pack.
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I am *not* the model of the modern major general. |
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| gyadavil |
| Posted: Wed Mar 14, 2007 3:51 pm Post subject: |
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Acolyte
Joined: 01 Feb 2005
Posts: 62
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[quote="jefflowrey"]Also, you can look at the Message Replay Server Support Pack.[/quote]
I am a new bee to pub/sub. Can you give me more details.
How I can avoid skip the subscribers who alredy received these when I am publishing the message with same topic again. |
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| gyadavil |
| Posted: Wed Mar 14, 2007 3:53 pm Post subject: Re: How to avoid duplicate Publications |
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Acolyte
Joined: 01 Feb 2005
Posts: 62
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[quote="Michael Dag"][quote="gyadavil"]He didn't receive 6,7,8 and 9th messages due to some error in the data or some other issue.[/quote] he WHAT! ? !
knowing pub/sub only in theory, isn't that what a [i]durable publication[/i] is all about? publications are stored for new subscribers so they can get 'back issues' aswell or if the subscriber is offline the publication can be retrieved later...[/quote]
I have problem with existing subscriptions. Due to some reason the message did not reach the subscriber, how do we resend these to the subscriber who need these instead of sending to all subscribers |
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| Michael Dag |
| Posted: Wed Mar 14, 2007 4:32 pm Post subject: Re: How to avoid duplicate Publications |
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Jedi Knight
Joined: 13 Jun 2002
Posts: 2607
Location: The Netherlands (Amsterdam)
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| gyadavil wrote: |
| Due to some reason the message did not reach the subscriber |
We are still talking about MQ pub/sub right? what was the reason (code) the subscriber got on getting the subscriptions?
I think you need to look at the cause rather then fixing the symptom
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Michael
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| gyadavil |
| Posted: Wed Mar 14, 2007 5:10 pm Post subject: Re: How to avoid duplicate Publications |
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Acolyte
Joined: 01 Feb 2005
Posts: 62
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[quote="Michael Dag"][quote="gyadavil"]Due to some reason the message did not reach the subscriber[/quote]
We are still talking about MQ pub/sub right? what was the reason (code) the subscriber got on getting the subscriptions?
I think you need to look at the cause rather then fixing the symptom[/quote]
Yes. MQ pub/sub only. MQ pub/sub or Message Broker pub/sub same right ??
One reason might be, configuration is wrong for subscriber connection details. Then in that case messages will end up in System.Dead.Letter.Queue. In such cases, if publisher want to publish the data again, then only the the subscriber having issue should get it instead of all other subscribers.
One more question I have here is ......when I have subscriber queue configuration wrong, the message is going to SDLQ...why this is not coming back to message flow as exception ?? |
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| fjb_saper |
| Posted: Thu Mar 15, 2007 2:56 am Post subject: Re: How to avoid duplicate Publications |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| gyadavil wrote: |
One more question I have here is ......when I have subscriber queue configuration wrong, the message is going to SDLQ...why this is not coming back to message flow as exception ?? |
The word is Asynchronous. For the broker the message put was O.K.
Now you need to resolve the DLQ problem (use a DLQ handler to redirect the messages where they should go).
To have true "redo" capabilities that are targetted at only a specific subscriber (late comer etc...) you need to treat your publications like a magazine publication:
you need an archive and a service to send back issues only to the requester...
Enjoy
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| jsware |
| Posted: Thu Mar 15, 2007 4:14 am Post subject: Re: How to avoid duplicate Publications |
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Chevalier
Joined: 17 May 2001
Posts: 455
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| gyadavil wrote: |
| Subscriber A got all of them but Subscriber B got only 1 to 5 and 10th message. He didn't receive 6,7,8 and 9th messages due to some error in the data or some other issue. |
If subscriber B failed because of a data error, wouldn't publishing the same data again cause the same problem? If you fix the data error, wouldn't both subscribers want the new copy?
Any way, not sure how you could do this without something like the replay server. My understanding is that publications retained by the broker only keep that last publication for a topic, not all "back issues". This allows a late subscriber to get the latest publication. For example, if a Stock/IBM topic retained the last trade price of IBM stock, a new subscriber would not have to wait until the next trade price change to know what the current trade price is. I am not aware that you can't get the trade price 5,6,7 or 8 price changes ago.
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Regards
John
The pain of low quaility far outlasts the joy of low price. |
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