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| tm |
 Posted: Wed Mar 19, 2003 4:33 am Post subject: MQGet plug-in (ia09) |
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Newbie
Joined: 19 Mar 2003
Posts: 1
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Is the MQGet plug-in code re-entrant? I don't have the source to hand.
What I'm seeing is this:
When multi-threading (additional instances == 1) a flow with the MQGet node in it, the MQGet node exhibits non-standard behaviour (e.g. not retrieving messages) once message volumes get high enough for multiple threads to be activated concurrently. As soon as the flow is returned to single-threading (i.e. additonal instances == 0, or low message volumes) , the problem goes away.
thanks
Tony |
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| kirani |
| Posted: Wed Mar 19, 2003 10:06 pm Post subject: |
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Jedi Knight
Joined: 05 Sep 2001
Posts: 3779
Location: Torrance, CA, USA
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Is it possible that there is no message on the queue with matching criteria at that time, the message arrives late?
_________________
Kiran
IBM Cert. Solution Designer & System Administrator - WBIMB V5
IBM Cert. Solutions Expert - WMQI
IBM Cert. Specialist - WMQI, MQSeries
IBM Cert. Developer - MQSeries
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| HOMETOWN47 |
| Posted: Thu Oct 07, 2004 1:43 am Post subject: |
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Apprentice
Joined: 25 Mar 2003
Posts: 34
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I've just posted the following question about a similar scenario
http://www.mqseries.net/phpBB2/viewtopic.php?t=18089&highlight=additional+instances
We have an MQGet plug-in node within our msg flow which should pick up a message that has previosuly been put onto a holding queue (we use a floworder node to put the message to the queue before the main body of the processing). We've noticed in the production region that the MQGet is not picking up the messages (we discovered this by wiring up the no mesage terminal of the MQ Get node). This would tie in with your theory as we have the execution group with additionl instances.
I'm currently testing this theory by resetting the additional instance setting to 0. will keep you updated with the results...
P.S
The messages are on the queue when we look at the q contents using utils available. |
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| fitzcaraldo |
| Posted: Thu Oct 07, 2004 9:52 pm Post subject: |
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Voyager
Joined: 05 May 2003
Posts: 98
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| The MQGet plugin is not re-entrant as far as I can see. My understanding is that CreateNodeContext entry point gets called once only regardless of the number of instances. The MQGet code mallocs the context (containing things like the message buffer) in that function meaning all instances share the same node context and no attempt is made to protect the resources. |
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| LH33 |
| Posted: Fri Oct 08, 2004 8:38 am Post subject: |
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Master
Joined: 21 Nov 2002
Posts: 200
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What version do you need to run the MQget plug-in? Where do you get the Plug-in?
Thanks! Lisa |
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| JT |
| Posted: Fri Oct 08, 2004 9:00 am Post subject: |
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Padawan
Joined: 27 Mar 2003
Posts: 1564
Location: Hartford, CT.
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Lisa,
Support for the IA09 supportpac has been withdrawn and IBM has a disclaimer that states:
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| The SupportPacs listed below have been withdrawn from download for general use, and are only available for backup purposes. Do not use these SupportPacs with new projects. |
In the past support for some v2 supportpacs has been withdrawn and then made available again once they were modified to support WBIMB v5. Since the MQGet plug-in appears to be popular, my feeling is it will return for general availability. |
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| LH33 |
| Posted: Fri Oct 08, 2004 9:02 am Post subject: |
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Master
Joined: 21 Nov 2002
Posts: 200
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Thanks for the information!
Do you know if anyone has written a Plug-in node that will get a mesage from another queue?
Thanks! Lisa |
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| kirani |
| Posted: Fri Oct 08, 2004 11:01 pm Post subject: |
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Jedi Knight
Joined: 05 Sep 2001
Posts: 3779
Location: Torrance, CA, USA
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Most of the people here have migrated the original MQGet plug-in node to WBIMB V5 successfully. You can also write your own plug-in for this function.
_________________
Kiran
IBM Cert. Solution Designer & System Administrator - WBIMB V5
IBM Cert. Solutions Expert - WMQI
IBM Cert. Specialist - WMQI, MQSeries
IBM Cert. Developer - MQSeries
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