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| BBM |
 Posted: Tue Dec 18, 2007 8:00 am Post subject: Handle Leak in MQ 6.0.2.1 for Windows |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
We have had a confirmed handle leak on MQ 6.0.2.1 for windows from IBM.
The circumstances are that when a non-existent queue or queue manager is addressed the QM will leak a handle. (2058 or 2085)
However we still puzzled why we are now leaking handles since this criteria is not being met any longer.
Has anyone else had any handle leak issues with 6.0.2.1 for windows?
Thanks
BBM |
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| tleichen |
| Posted: Tue Dec 18, 2007 8:19 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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Out of curiosity, what version of Windows are you working with?
_________________
IBM Certified MQSeries Specialist
IBM Certified MQSeries Developer |
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| BBM |
| Posted: Tue Dec 18, 2007 8:24 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
We've observed the handle leak on both Win 2K server SP4 and W2K3 Server SP2.
The handle leak is from the dllhost process - we're using Biztalk as the messages broker which uses COM+ to communicate with MQ.
Never an issue in 5.3.x
Cheers
BBM |
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| mvic |
| Posted: Tue Dec 18, 2007 9:38 am Post subject: Re: Handle Leak in MQ 6.0.2.1 for Windows |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| BBM wrote: |
| Has anyone else had any handle leak issues with 6.0.2.1 for windows? |
If true, and is observed with the latest fix pack, then it needs to be investigated by IBM support. IMHO |
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| BBM |
| Posted: Wed Dec 19, 2007 2:30 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
We have an open PMR with the labs at Hursley. They are drawing a blank as all traces and adplus dumps have not pointed to anything useful.
They have also indicated that the issue could be with Microsoft's COM+ code. Microsoft have also investigated and have been similiarly frustrated with not being able to diagnose from the dumps.
We can reliably repro the issue but the handles shown in the dumps are not named even with the correct symbols loaded.
We've seen several handle leaks with MQ over the years - which have subsequently been patched. I'm wondering if anyone here has experienced anything with 6.x that has not been resolved? This may then point us in the right direction.
Incidentally if you are running Qpasa - we have identified an issue (mentioned earlier) that manifests itself when you are attempting to monitor non-existent queues - for eg when some queues have been deleted, but not removed from Qpasa. This then causes a handle leak - IBM has produced an APAR for this and it will be in the next release.
Thanks |
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| ashu |
| Posted: Wed Dec 19, 2007 2:40 am Post subject: |
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Centurion
Joined: 11 Nov 2006
Posts: 132
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Sorry to interrupt but can anyone of you give me a pointer to the dicussion about what is a handle leak? 
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Ashu
"It is simple to be Happy but difficult to be Simple" |
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| BBM |
| Posted: Wed Dec 19, 2007 2:43 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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| ashu |
| Posted: Wed Dec 19, 2007 2:45 am Post subject: |
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Centurion
Joined: 11 Nov 2006
Posts: 132
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ACK:Thanks
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Ashu
"It is simple to be Happy but difficult to be Simple" |
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| PeterPotkay |
| Posted: Wed Dec 19, 2007 6:56 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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BBM,
I have a couple pf QMs each running on Windows 2003 SP1 (2 node MSCS) running MQ 6.0.2.1 and QPASA and Biztalk.
No problems so far. How long does your QM run before you see the problem? How do you know you have handle leaks, what are the symptoms?
Tell those apps to use real q names! 
_________________
Peter Potkay
Keep Calm and MQ On |
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| BBM |
| Posted: Thu Dec 20, 2007 5:04 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi Peter,
Thanks for the reply.
We are running BTS 2006 against our QMs.
The symptoms are that pretty soon after bringing up the send/recv hosts on the BTS server the handle count for process DLLHOST.exe rises and keeps rising. It will keep going at a rate of increase of about 10k handles a day until it gets to around 140k and crashes.
When this happens repeatedly over time the whole server comes down, so we are currently doing preemptive reboots on the MQ server to mitigate the risk.
Your comment may well prove to be correct we have a fair number of clients connecting to us and some may be using incorrect queue names potentially exposing the bug. I wonder if there is a way to trap API return codes to clients.
The problem is not confined to just one system and the only common denominator is MQ 6.0.2.1. COM+, BTS MQ adapter, O/S versions are varied amongst our estate, so we doubt they could be a factor.
Just out interest what is the handle count for DLLHOST on your systems?
Cheers
BBM |
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| jefflowrey |
| Posted: Thu Dec 20, 2007 5:39 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Why do you think it's a bug in MQ, and not in COM+ or BTS MQ Adapter?
Maybe BTS adapter is leaking handles... ?
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I am *not* the model of the modern major general. |
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| BBM |
| Posted: Thu Dec 20, 2007 5:51 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
This is a good question. We are running (in some cases) the same version of BTS MQ adapter as we were with 5.3, in 5.3 we didn't see the problem.
Regardless of the version of COM+, BTS MQ adapter or OS version we are seeing the problem with MQ 6.0.2.1.
It may be a general problem with 6.0.2.1 and Biztalk but I'm sure its more specific. Microsoft's product team for Biztalk cannot find anything in our Windbg/adplus/ttt dumps to suggest either COM+ or BTS MQ adapter issues.
In most cases the only thing we changed when we upgraded was MQ version - in all cases we have the issue.
Cheers
BBM |
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| jefflowrey |
| Posted: Thu Dec 20, 2007 6:01 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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...
Is there a newer version of the BTS adapter available?
It's not uncommon for software vendors of all kinds and ilks to quietly fix bugs in things, and not a) log them properly for support, b) not go out of their way to admit that they had any such bugs in the first place.
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I am *not* the model of the modern major general. |
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| BBM |
| Posted: Thu Dec 20, 2007 8:04 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
We have the latest hotfixes from Microsoft on for the BTS adapter. As mentioned the same stack with 5.3 does not exhibit the leak.
There is a fix for a different problem that we had that was originally slated for 6.0.2.4 but will now be in 6.0.2.3 - but our issue is different.
Cheers
BBM |
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| PeterPotkay |
| Posted: Thu Dec 20, 2007 5:15 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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| BBM wrote: |
....so we are currently doing preemptive reboots....
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Vitor, you're slipping!
| BBM wrote: |
Your comment may well prove to be correct we have a fair number of clients connecting to us and some may be using incorrect queue names potentially exposing the bug. I wonder if there is a way to trap API return codes to clients.
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Just turn on local events at the QM level. That will produce events showing you the bad q names, which may be enough for you to hunt down the culprit based on the times and/or names.
| BBM wrote: |
Just out interest what is the handle count for DLLHOST on your systems?
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I'll check tomorrow. We are still at version 2004 for the MQS Agent though.
_________________
Peter Potkay
Keep Calm and MQ On |
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