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| imrakesh |
 Posted: Tue May 08, 2012 9:45 am Post subject: Impact if changing MaxDepth from 5k to 1000k |
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Novice
Joined: 10 Apr 2012
Posts: 10
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Any idea if we change the MAXDEPTH(5000) to 1000K.
Its only for one queue.
And i also believe we need to change the system dead letter queue.
am i right ?
Please advice |
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| Vitor |
| Posted: Tue May 08, 2012 10:28 am Post subject: Re: Impact if changing MaxDepth from 5k to 1000k |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| imrakesh wrote: |
Any idea if we change the MAXDEPTH(5000) to 1000K.
Its only for one queue. |
You'll need to have enough space (available or defined according to platform) for the queue. You might also want to think about corresponding increases to the queue manager's log.
If your application is doing any kind of matching and/or browsing you should also increase your SLA exponentially.
| imrakesh wrote: |
And i also believe we need to change the system dead letter queue.
am i right ? |
No. Why would you need to change that?
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| zpat |
| Posted: Tue May 08, 2012 10:31 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5849
Location: UK
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Changing the maxdepth value has no effect on space.
Storing more messages on the queue will have an effect. |
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| Vitor |
| Posted: Tue May 08, 2012 10:38 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| zpat wrote: |
| Storing more messages on the queue will have an effect. |
So if you're increasing the number because 5000 sounds too small or seems unlucky then you don't need to worry about space.
If you're increasing it because the queue keeps filling then you need to consider having more space. Especially if you're increasing it by a ludicrously large amount (i.e. to the maximum possible value) because it's easier than working out why it keeps filling up & there's a strong chance you'll end up with that number of records on it one day.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| bruce2359 |
| Posted: Tue May 08, 2012 12:43 pm Post subject: Re: Impact if changing MaxDepth from 5k to 1000k |
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Poobah
Joined: 05 Jan 2008
Posts: 9399
Location: US: west coast, almost. Otherwise, enroute.
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| imrakesh wrote: |
And i also believe we need to change the system dead letter queue.
am i right ? |
Whichever dead-letter queue you are using (SYSTEM.DEAD.LETTER.QUEUE or other) needs to have maxdepth set high enough to accommodate as many undeliverable messages as might occur.
As my worthy colleague stated earlier, increasing (or decreasing) the maxdepth queue attribute does not itself impact disk space. Rather, it is the arrival of messages in the queue that takes disk space.
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| mqjeff |
| Posted: Tue May 08, 2012 12:50 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| And honestly, it is a reduction in maxdepth that is more likely to affect the S.D.L.Q than an increase in maxdepth - more chance that the queue will get full! |
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| bruce2359 |
| Posted: Tue May 08, 2012 1:33 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9399
Location: US: west coast, almost. Otherwise, enroute.
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I only offered the 'or decreasing' for those that have come to believe that reducing maxdepth saves disk space, like increasing maxdepth wastes disk space.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| gbaddeley |
| Posted: Tue May 08, 2012 10:52 pm Post subject: Re: Impact if changing MaxDepth from 5k to 1000k |
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Jedi
Joined: 25 Mar 2003
Posts: 2495
Location: Melbourne, Australia
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| imrakesh wrote: |
Any idea if we change the MAXDEPTH(5000) to 1000K.
Its only for one queue. |
It won't immediately change any disk space allocation or usage, its just an upper limit that MQ checks every time a messages is put to the queue.
You need to consider capacity planning when setting MAXDEPTH.
How many messages does this queue need to hold in situations when the consumer app is running and not running? Ideally this is quite a low number (eg. < 1000), but it could be quite high (eg. many messages are put during the day and a batch job runs at night to process all the queued messages).
Calculate the maximum disk space requirement. Its approximately # queued messages * (average message data size + 500 ).
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Glenn |
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