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| ChrisW |
 Posted: Wed Oct 17, 2007 4:09 am Post subject: Does MQ count messages on startup? |
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Voyager
Joined: 20 May 2001
Posts: 78
Location: UK
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Just trying to explain this behaviour........
We have a Queue Manager that currently holds 6.5 million messages pending processing. I know thats not a good thing but politics, priorities etc. They are working on it.
In order to add some more disk space we stopped the Queue Manager to be on the safe side and consolidate the queue files (AIX/5.3 - upgrade to 6 soon), added the extra space, and restarted the QM. No problems and all processes connected OK. But when doing a display of queue depths, all the big queues took up to 5 minutes to display the current depth of each one (say average 200,000 messages on each). Once they were displayed, then the count returned immediately.
So I assume that MQ stores the message counts in memory and then updates there as messages put/got, and either counts the messages asyncronously on startup, or counts them on the first request for the curdepth.
Does anyone know which of the above applies, or knows better?
Thanks, Chris. |
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| Gaya3 |
| Posted: Wed Oct 17, 2007 4:23 am Post subject: |
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Jedi
Joined: 12 Sep 2006
Posts: 2493
Location: Boston, US
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Hi
I never heard of storing the Message count or current depth in memory.
I do know that only the persistent messages will be backed.
Regards
Gayathri
_________________
Regards
Gayathri
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Do Something Before you Die |
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| vmcgloin |
| Posted: Wed Oct 17, 2007 6:33 am Post subject: |
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Knight
Joined: 04 Apr 2002
Posts: 560
Location: Scotland
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| How are you displaying the queue depths? MQExplorer (which version)? runmqsc? |
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| mvic |
| Posted: Wed Oct 17, 2007 8:20 am Post subject: Re: Does MQ count messages on startup? |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| ChrisW wrote: |
So I assume that MQ stores the message counts in memory and then updates there as messages put/got, and either counts the messages asyncronously on startup, or counts them on the first request for the curdepth.
Does anyone know which of the above applies, or knows better? |
The queue manager doesn't know the depth of a queue until your application (or runmqsc, channel rcvr program, etc.) accesses the queue for the first time. Does that answer the question(s)? |
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| ChrisW |
| Posted: Wed Oct 17, 2007 11:06 pm Post subject: |
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Voyager
Joined: 20 May 2001
Posts: 78
Location: UK
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| Thanks mvic. That makes sense. Was using both runmqsc and in-house written display program. I just never really thought about it before. |
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| PeterPotkay |
| Posted: Thu Oct 18, 2007 4:51 am Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Chris, what version of MQ are you on?
_________________
Peter Potkay
Keep Calm and MQ On |
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| ChrisW |
| Posted: Thu Oct 18, 2007 6:51 am Post subject: |
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Voyager
Joined: 20 May 2001
Posts: 78
Location: UK
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| 5.3 CSD12. Upgrade to 6 soon I hope (keeps me in work). |
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