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| sivaram_mca |
 Posted: Tue Oct 04, 2005 3:36 am Post subject: why the queues are often hanging |
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Newbie
Joined: 04 Oct 2005
Posts: 5
Location: chennai
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| In which situations the queues of ibm mq may hang and what are solutions for it. |
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| wschutz |
| Posted: Tue Oct 04, 2005 4:24 am Post subject: |
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Jedi Knight
Joined: 02 Jun 2005
Posts: 3316
Location: IBM (retired)
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Can you give more details of your problem? You haven't given enought information for us to help you.
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-wayne |
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| sivaram_mca |
| Posted: Tue Oct 04, 2005 4:40 am Post subject: Websphere MQ Problem |
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Newbie
Joined: 04 Oct 2005
Posts: 5
Location: chennai
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Hi
Websphere MQ hangs sometimes in our production environment spontaneously. We dont know reason behind and we assume the system is not restarted for a long time. When we restart the system the queues are set right. We are not able to get the data from the hanged queues even if we run the process definition from command prompt. The messages all of a sudden disappear and we have to resend the request to get the responses.
On what occasions the triggermonitor fails??? |
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| jefflowrey |
| Posted: Tue Oct 04, 2005 4:43 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Queues don't hang.
They are data stores - like a database table. Database tables don't hang.
Database server processes may hang. Similarly, MQ server processes may hang... but almost never.
Applications hang all the time. Because programmers are sloppy.
_________________
I am *not* the model of the modern major general. |
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| sivaram_mca |
| Posted: Tue Oct 04, 2005 4:51 am Post subject: MQ Problem |
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Newbie
Joined: 04 Oct 2005
Posts: 5
Location: chennai
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Hey
Queue hangs means the Queuemanager is not responding . The trigger failing. That to not all times when the queuemanagers are heavily loaded. It even goes to the no response state when the server is loaded less |
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| fjb_saper |
| Posted: Tue Oct 04, 2005 5:23 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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If you are working in a request response pattern and the server does not respond you might check a number of things
a) do the messages have an expiry time set and has it been reached ?
Reasons for that can be
a -1) Network problems
a -2) Load problems -- expiry happens before the message can be read
b) are your messages non persistent ?
b -1) Network problems may cause loss of messages at the channel level.
Under network problems add bandwidth usage...
So you see the problems may be caused by a number of things completely out of the MQ responsability domain....
As well if you are working with triggering you might want to make sure the trigger is set to run a background process so that the next queue triggering doesn't have to wait until your triggered process is done....
Enjoy  |
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| hopsala |
| Posted: Tue Oct 04, 2005 5:49 am Post subject: Re: MQ Problem |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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| sivaram_mca wrote: |
| Queue hangs means the Queuemanager is not responding |
You must look in the error logs; even though mq rarely hangs, there are too many possible reasons, listing them all is not applicable.
| sivaram_mca wrote: |
| The trigger failing. That to not all times when the queuemanagers are heavily loaded. It even goes to the no response state when the server is loaded less |
I'm afraid your English is very unclear, so I can't quite get what you're trying to say; what do you mean by "trigger failing"? do you mean the trigger monitor crashes? Or simply that the mechanism doesn't work?
I recommned you read the triggering chapter (application programming guide) thouroughly, many people who think they know the proper conditions for a trigger to occur are surprised to see they had no knowledge of many important case scenarios.
| sivaram_mca wrote: |
| When we restart the system the queues are set right. We are not able to get the data from the hanged queues even if we run the process definition from command prompt. The messages all of a sudden disappear and we have to resend the request to get the responses. |
Well, two options, the first one being more likely: Either you are using non-persistent messages, which are deleted on restart by design, or you're application gets them and throws them away.
Read the manuals concerning persistent and non-persistent messages, it's a very (!) important topic. |
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| sivaram_mca |
| Posted: Wed Oct 05, 2005 3:33 am Post subject: |
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Newbie
Joined: 04 Oct 2005
Posts: 5
Location: chennai
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| yes our messages are non persistent,if we use persistence mechnism it will slower the performance of the application,then what is the solution for it without using persistence messages sir |
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| sivaram_mca |
| Posted: Wed Oct 05, 2005 3:36 am Post subject: |
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Newbie
Joined: 04 Oct 2005
Posts: 5
Location: chennai
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| "Trigger failing" means simply that the mechanism doesn't work sir |
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| hopsala |
| Posted: Wed Oct 05, 2005 4:16 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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| sivaram_mca wrote: |
| yes our messages are non persistent,if we use persistence mechnism it will slower the performance of the application,then what is the solution for it without using persistence messages sir |
Sir eh? 
You see, old chap, I fear that yonder WMQ deletes non-persistent messages upon restart by design; additionally, channels that encounter a problematic non-persistent msg and use NPMSPEED(FAST) will simply chuck the message. There is no way to change this behavior, other than to work with persistent messages; that's what non-persistent means - non recoverable. Bear in mind, "faster"/"slower" is of no importance, there is only "fast enough" according to one's needs.
Concerning performance, it is true that usually there's a good 30% degredation when switching to persistent messags, but most sites do not need half the speed WMQ provides anyhow; I advise you try switching to persistent messages, most probably it will be fast enough, even jolly faster than you require.
Yours Sincerely,
Lord Hopsala Humpton Pompernickle Esq. |
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| hopsala |
| Posted: Wed Oct 05, 2005 4:19 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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| sivaram_mca wrote: |
| "Trigger failing" means simply that the mechanism doesn't work sir |
Ah, but where are the details, man? Definitions, error log entries, exact pathological description of occurrences, what what? |
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| Nigelg |
| Posted: Wed Oct 05, 2005 4:31 am Post subject: |
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Grand Master
Joined: 02 Aug 2004
Posts: 1046
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The trigger mechanism DOES work.
Please check that the 14 conditions for triggering ave been met before you assert that it does not work.
As hopsala says, where are the detrails?
BTW, people in England do not really talk like that...
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| hopsala |
| Posted: Wed Oct 05, 2005 5:47 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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| Nigelg wrote: |
| BTW, people in England do not really talk like that... |
Apologies, but sivaram's twofold repetition of "sir" at the end of each sentence triggered some recondite genetic Elizabethian self 
p.s congrats on newly annoited grand-masterism! |
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| MQnewbee |
| Posted: Tue Nov 01, 2005 5:41 pm Post subject: Remove Dead Message from the queue |
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Newbie
Joined: 17 Oct 2005
Posts: 7
Location: USA
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Hi,
Does any know how to remove dead message from the queue?
Our system received a message which throws a exception error and it's been kept throwing back to the queue for the system to reprocess it. There are some code fixes need to be done in the system down the road.
Is there any quick way to remove the dead message from MQ 5.3. Please advice.
Thanks! |
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| Mr Butcher |
| Posted: Tue Nov 01, 2005 11:40 pm Post subject: |
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Padawan
Joined: 23 May 2005
Posts: 1716
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newbee, your post is not related to this thread, you should create your own thread.
anyway, what is a dead message? a message in the dead letter queue or just in any other queue?
if you want to delete a message (or all) in the queue there is a clear qlocal command, or use some of the tools around to get the message from the queue, or use one of the supplied samples (amqsget) or or
or .....
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Regards, Butcher |
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