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| gunner |
 Posted: Mon Jul 19, 2004 6:58 am Post subject: MQSeries 2.2.0.1 listener hang issue-Client 5.1 connections |
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Newbie
Joined: 19 Jul 2004
Posts: 3
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We are experiencing an intermittent issue which results in the listener on an external instance of MQ Server hanging, which requires a support person to restart.
The environments are:
A VB6 appliction using MQ Client 5.1 running on an Windows NT server, connecting to a business customer who is running MQ Server 2.2.0.1 on a Tandem.
Currently our VB application functions as follows:
On each application "loop":
Connect to Queue Manager
Connect to Queue 1
Process Messages
Disconnect from Queue 1
Connect to Queue 2
Process Messages
Disconnect from Queue 2
Etc.
Disconnect from Queue Manager
This application runs constantly, 24x7. Every couple of weeks the people on the server side find that the listener hangs, which results in a call out to restart. The people on the server side, sees the connection as always being open and never sees our disconnections.
Our code is definitely disconnection and we are setting our objects to NOTHING.
At one point we changed the application flow to:
Connect to Queue Manager once on application startup
On each application "loop":
Connect to Queue 1
Process Messages
Disconnect from Queue 1
Connect to Queue 2
Process Messages
Disconnect from Queue 2
Etc.
Disconnect from Queue Manager on application shutdown
This actually resulted in the listener hanging every 2 hours like clockwork.
Anyone got any ideas ?
TIA |
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| fjb_saper |
| Posted: Mon Jul 19, 2004 11:32 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Are you sure you are releasing the resources right ?
Just disconnecting won't do it.
F.J.  |
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| gunner |
| Posted: Mon Jul 19, 2004 10:51 pm Post subject: |
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Newbie
Joined: 19 Jul 2004
Posts: 3
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Thanks for the response !.
We are doing a .close for the Queues followed by a set to Nothing and a .disconnect from the QueueManager followed by a SET obj = NOTHING.
We also set the MQSession to nothing
Is there something else we should be doing do you think ? |
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| fjb_saper |
| Posted: Tue Jul 20, 2004 10:01 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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I am more familiar with the JMS environment but I will take a shot at it here:
close queue
disconnect queue
set object to null
close session
disconnect session
set object to null
close qmgr
disconnect qmgr
set object to null
You will need to check the functionality. Close/disconnect might be synonyms in some cases.
If it were JMS:
commit/rollback session
stop connection
close sender / receiver
close session
close connection ( might not be possible after session close)
done
FJ |
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| gunter |
| Posted: Tue Jul 20, 2004 10:58 pm Post subject: |
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Partisan
Joined: 21 Jan 2004
Posts: 307
Location: Germany, Frankfurt
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If a strange problem arises, I'll always ask:
- operating system ?
- mq version ?
- CSD level ?
Did you find anything in the qmgr error log or in the system event log ?
_________________
Gunter Jeschawitz
IBM Certified System Administrator - Websphere MQ, 5.3 |
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| gunner |
| Posted: Wed Jul 21, 2004 1:15 am Post subject: |
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Newbie
Joined: 19 Jul 2004
Posts: 3
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Gunter, thanks for the reply.
MQ Client 5.1 from a VB6 application running on Window 2000 connecting
to a Tandem running MQ Server V2.2.0.1 PTF U473441.
We have no control over the Server as it is owned by a customer. They tell us that they do not see us disconnecting from their listener. There doesn't seem to be much information available from the Server.
Would detailed trace logs from MQ client be off any use ?
thanks |
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| gunter |
| Posted: Wed Jul 21, 2004 1:47 am Post subject: |
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Partisan
Joined: 21 Jan 2004
Posts: 307
Location: Germany, Frankfurt
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We had a few years ago a problem with hanging listener. That wasn't a client connection, we had problems with channels. The solution was to set AdoptNewMCA in the queuemanager configuration. I do'n't know if this is also a possible solution for client connection problems and I don't know if this parameter exists in your version.
Our problem was always related to network problems. The sender stopped by error and the receiver was still running. The listener didn't accepted furter connections.
_________________
Gunter Jeschawitz
IBM Certified System Administrator - Websphere MQ, 5.3 |
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| fjb_saper |
| Posted: Wed Jul 21, 2004 12:05 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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There is another thing you should consider.
Always use MessageListener and ExceptionListener as a pair.
If there is no message and you are waiting but there is a connection problem I would expect that you might get something on the exception listener. You could then try to actively close and reopen the connection.
This should help clear up some resources.
Hope it helps some
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