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| C# and MQQueueManager instances |
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| joehuber |
 Posted: Fri Oct 22, 2004 5:40 am Post subject: C# and MQQueueManager instances |
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Newbie
Joined: 08 Oct 2004
Posts: 7
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Hello,
I am using the IBM provided MQ .NET classes to access a z/OS queue server from a windows XP machine. I use multiple instances of the MQQueueManager class at a time but I have discovered that disconnecting from one causes all the other manager instances to become invalid with 2018 Connection Handle Not Valid.
Here is how my app works. I create an instance of MQQueueManger and read a message from a queue. I then send that message to a thread to be processed. When the thread is complete it commits the manager and disconnects. While it is processing other instances of MQQueueManager are created and used to read additional messages from the same queue. The first thread does a commit without problem then disconnects. However, the second queue fails when it tries to commit (with error 2018).
It appears that disconnection one manager causes the connection to be broken for all existing managers. Is this how it is supposed to work or do I have some kind of configuration/setup problem?
Also, I could change the program to create only one MQQueueManager instance and use it across all threads. In that case, I could commit at the end of each thread but I would never disconnect. My application is a service so it could run indefinitely. Do you see a problem with keeping the manager connected over long periods of time?
Thanks,
Joe Huber |
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| jefflowrey |
| Posted: Fri Oct 22, 2004 6:05 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Create each instance inside your "processing" thread.
But it is a much better idea to connect once, do lots of work, and then disconnect, than it is to connect and disconnect many times.
So, yeah, share the connection.
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I am *not* the model of the modern major general. |
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| joehuber |
| Posted: Fri Oct 22, 2004 6:26 am Post subject: Another question |
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Newbie
Joined: 08 Oct 2004
Posts: 7
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Thanks Jeff.
I have found another problem. I tried using just one QueueManager that was shared by all threads. It worked fine when I was accessing only one queue. However, when I expanded my app to reading from 3 different queues I again got the 2018 error whenever I tried to read from the 2nd or 3rd queue (the first queue worked throughout the test). Is there some connection between a QueueManager and a queue? I assumed a manager could be used to read many queues.
Also, do you see any potential issues with keeping the manager connected for long periods of time such as days or weeks? |
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| jefflowrey |
| Posted: Fri Oct 22, 2004 6:46 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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You'll want to make sure your connection will FAIL_IF_QUIESCING, so you can shut down your queue manager.
Otherwise, it's not a big deal to leave it open. Trigger Monitors do it all the time!
You might be running into issues where you have not opened the handle to allow for sharing. That's a usual cause of 2018s when working with threads.
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I am *not* the model of the modern major general. |
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