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| High(100%) CPU usage with Triggered Application |
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| zpat |
 Posted: Tue Dec 07, 2010 7:39 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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Polling (yuck) and triggering are not the only options.
A long running process with an outstanding MQGET WAIT is often the best for anything relatively high volume. This is what the IBM message broker does for example for MQ input nodes. |
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| Mr Butcher |
| Posted: Tue Dec 07, 2010 7:43 am Post subject: |
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Padawan
Joined: 23 May 2005
Posts: 1716
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| Quote: |
| Whats the way to make it work if I dont want the app to get retriggered until certain interval? |
These both mechanisms to trigger do not depend on each other.
if a queue is tirggered first and the (last) application closes the queue leaving it not empty and all the other trigger conditions are met, a new trigger is genereated, no matter how your trigint settings are.
there is no "trigger after time" - mechanism. you could trigger by depth 1 which is the same like trigger first, but queue is then set to "notrigger". you need a mechanism to set the queue back to "trigger". i wont do that.
whats wrong with being started again by the trigger monitor if there are messages on the queue left after 1000 have been consumed and your application terminates?
i'd also suggest to remove that "end after 1000 messages". why do you do that? what becomes for efficient by doing that? (as you said it is for efficiency) ?!?
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Regards, Butcher |
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| mdfaraz |
| Posted: Tue Dec 07, 2010 8:09 am Post subject: |
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Novice
Joined: 31 Mar 2010
Posts: 19
Location: Houston, TX
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I wanted to have a mechanism to stop the app anytime while its processing messages. Even if there are still messages to be processed, I want to stop processing and exit. So I have logic in the while loop for processing messages, to look at a flag in a DB table. If its set to true, then continue processing, if its set to false, exit the while loop(and the program). What I meant by checking after 1000 is, I don't want to keep hitting the DB for this value while processing messages. but I do it every 1000 iterations. The algorithm is
Sub ProcessQueue
Connect to QMGR
Open Queue
dim b as boolean=true
Do
Try
For every 1000th iteration, Check if Enabled
If Enabled, Continue, else exit
Queue.GET()
Process message
Catch exception
b=false
While b=True
Cleanup code
End Sub
Whenever we want these apps to exit, we set this enabled flag in DB to false. so within the processing of next 1000 messages, the app exit. At this point, I want my app not to start again(atleast not instantly). I thought triggerinterval is the property that will determine when to start the app next. Looks like its not. |
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| mqjeff |
| Posted: Tue Dec 07, 2010 8:25 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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If there are still messages on the queue, you will get retriggered.
If you want to halt triggering, your program can alter the properties of the queue to stop the trigger message from being generated. |
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| Vitor |
| Posted: Tue Dec 07, 2010 9:06 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| mdfaraz wrote: |
| I thought triggerinterval is the property that will determine when to start the app next. Looks like its not. |
No, it's not.
If you want to stop this application then whatever mechanism used to set or unset this flag on the database table must be modified to switch triggering on or off.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| Vitor |
| Posted: Tue Dec 07, 2010 9:06 am Post subject: Re: Miracle! |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| mdfaraz wrote: |
| I just cudn't believe how following best practices affected the performance by 2000%! |
They're called "best" for a reason. 
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| Mr Butcher |
| Posted: Tue Dec 07, 2010 11:39 pm Post subject: |
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Padawan
Joined: 23 May 2005
Posts: 1716
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as already been written, setting the db flag to make your program exit is not enough. your program will terminate, but will be re-triggered by mq immediately if the queue is left non-empty.
i would the get-enable / disable attribute of the queue for that.
in the program, catch the proper returncode and exit if the queue is get-disabled (dont forget do commit everything else before that has been completed).
get-disable will also prevent mq from creating a new trigger, as one of the trigger conditions is that the queue must be get-enabled.
if you get-enable the queue again (and all the other tirgger conditions are met), a new trigger is created automatically and your program is started again.
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Regards, Butcher |
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