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| want to discuss "You CANNOT use the CCDT for the MDBs&q |
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| sebastia |
 Posted: Mon Apr 06, 2009 1:42 am Post subject: want to discuss "You CANNOT use the CCDT for the MDBs&q |
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Grand Master
Joined: 07 Oct 2004
Posts: 1003
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First of all, let me admit I know almost nothing about MDBs.
But have read "http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/MDB.html".
If it is a piece of code that waits on a JMS queue for a message,
why cant I use a Channel Table for it ?
One reason I can imagine is that you dont know the Queue Manager you get connected to, but I can fix that using MQ_Inquiry().
A related phrase is
"You should not be using MDB for a request / reply model"
And I would like to know the reason why.
If MDB waits on a JMS queue, and gets a Request message,
indicating ReplyToQueue and ReplyToQueueManager,
why our MDB cant send the Reply there ?
mr Saper : I am NOT saying your sentences are wrong !!!
... IN ANY WAY !!!!
Just want 2 lines more of explanation of your sentences,
or (as always) a pointer to where the answer is
[except a pointer to InfoCenter, please ]
My situation at customer is similar, but diferent :
code in WAS connects to MQ Server (Wintel) using CCDT,
sends a Request message to z/OS
and waits for the Response for a 3 second period.
We are the Requester in this Request/Response situation,
or may I say we are the "client",
while in your description the MDB was the "server" part of it.
My "real" question is : can I use CCDT in my situation ?
And I can't see why not ... |
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| Vitor |
| Posted: Mon Apr 06, 2009 1:49 am Post subject: Re: want to discuss "You CANNOT use the CCDT for the MD |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| sebastia wrote: |
mr Saper : I am NOT saying your sentences are wrong !!!
... IN ANY WAY !!!!
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Can I suggest you include links (using the url tag if you please) to the previous threads where "Mr Saper" said this? It might give us some backgorund.....
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Honesty is the best policy.
Insanity is the best defence. |
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| sebastia |
| Posted: Mon Apr 06, 2009 2:08 am Post subject: |
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Grand Master
Joined: 07 Oct 2004
Posts: 1003
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| fjb_saper |
| Posted: Mon Apr 06, 2009 3:46 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Use whatever you want as requester.
The reason I discourage the use of an MDB for the reply to Destination as requester is that your are looking for a message with a particular correlation Id. You don't want to go changing the message selector on your MDB setup for every message... and I have never seen an MDB setup for a dynamic temporary queue (don't even think it would be possible to do it in the first place... wouldn't make any sense, at least to me...)
The reason I said the CCDT is not suited for an MDB is that you don't know which qmgr you are connected to. Ideal for request / reply failover...
For an MDB however that means that you can only process the queue from the qmgr you are connected to. Typically what happens is that you have multiple qmgrs sharing the load. The app then needs to have an MDB processing the queue on EACH qmgr hosting the queue. (i.e. with 3 qmgrs sharing the load, 3 MDBs for the same queue, one on each of the 3 qmgrs sharing the load).
Not written in any manual... just plain common sense.
Have fun. 
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| sebastia |
| Posted: Mon Apr 06, 2009 5:15 am Post subject: |
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Grand Master
Joined: 07 Oct 2004
Posts: 1003
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OK - I agree completely with you.
Being a MDB as a "server", the CCDT complicates your life,
and you have to create an instance on every responder.
Thanks for your patience.
Just wanted to be sure about my "Requester" WAS code plus CCDT.
Once you said "ideal", I am happy again.
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