| Author | Message | 
		
		  | sammyG | 
			  
				|  Posted: Tue May 15, 2007 6:21 am    Post subject: What is the size of an empty MQ message? |   |  | 
		
		  | Novice
 
 
 Joined: 15 May 2007Posts: 10
 
 
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				| I'd like to know what the minimum size of an MQ message is. That is, with an empty message body, how many bytes does the message take up when transmitted on the wire? 
 if no one knows, i'd settle for an easy way to find out.
 
 thanks,
 
 sam
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		  | tleichen | 
			  
				|  Posted: Tue May 15, 2007 6:52 am    Post subject: |   |  | 
		
		  | Yatiri
 
 
 Joined: 11 Apr 2005Posts: 663
 Location: Center of the USA
 
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				| Minimally, it's the size of the message descriptor that you are using.  There are a couple different sizes of MDs, depending on which version of the MD you are using.  This of course, does not count any low-level communication headers, etc.  Are you interested in this from a "data on the queue" perspective, or are you interested in communication bandwidth?  _________________
 IBM Certified MQSeries Specialist
 IBM Certified MQSeries Developer
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		  | bruce2359 | 
			  
				|  Posted: Tue May 15, 2007 6:53 am    Post subject: |   |  | 
		
		  | Guest
 
 
 
 
 
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				| A message desciptor (MQMD) accompanies every message.  When the message arrives in a transmission queue, a transmision queue header (XQH) is added to you message (MQMD and your application data).  This is what gets sent on the network. 
 Refer to the MQ V6 Application Programming Reference.
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		  | sammyG | 
			  
				|  Posted: Tue May 15, 2007 6:54 am    Post subject: |   |  | 
		
		  | Novice
 
 
 Joined: 15 May 2007Posts: 10
 
 
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				| i'm interested in communication bandwidth. 
 thanks for replies so far..
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		  | EddieA | 
			  
				|  Posted: Tue May 15, 2007 10:32 am    Post subject: |   |  | 
		
		  |  Jedi
 
 
 Joined: 28 Jun 2001Posts: 2453
 Location: Los Angeles
 
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				| No doubt, MQ adds more for the actual wire transmission.  But, they aren't going to document that. 
 Try a "sniffer".
 
 Cheers.
 _________________
 Eddie Atherton
 IBM Certified Solution Developer - WebSphere Message Broker V6.1
 IBM Certified Solution Developer - WebSphere Message Broker V7.0
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		  | bruce2359 | 
			  
				|  Posted: Tue May 15, 2007 10:49 am    Post subject: |   |  | 
		
		  | Guest
 
 
 
 
 
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				| Message channels send messages in one direction only; but there is back and forth communication on the channel between MCA's (Message Channel Agents) to keep the channels in syncronization. |  | 
		
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		  | Michael Dag | 
			  
				|  Posted: Tue May 15, 2007 12:17 pm    Post subject: |   |  | 
		
		  |  Jedi Knight
 
 
 Joined: 13 Jun 2002Posts: 2607
 Location: The Netherlands (Amsterdam)
 
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				| 
   
	| sammyG wrote: |  
	| i'm interested in communication bandwidth. 
 thanks for replies so far..
 |  If your concern is that you don't have enough bandwidth you can look at the channel compression options (assuming you are on V6), MQ will compress the data before sending...
 _________________
 Michael
 
 
   
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		  | sammyG | 
			  
				|  Posted: Wed May 16, 2007 1:30 am    Post subject: |   |  | 
		
		  | Novice
 
 
 Joined: 15 May 2007Posts: 10
 
 
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				| I think that a sniffer would give the most complete answer given the various points raised (and without trying to figure out how various options/platforms/encoding etc etc change the result). 
 I'm interested in the channel compression option but our counterparty has told us that a) they use v5.x and b) they have found compression to be very difficult to work with.
 
 So, is v6 and v5.x compression compatible?
 
 and is it very hard to set up? bearing in mind that they are alleged experts and I am a total newbie. my experience with MQ is pressing next..next..finish on the install.
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		  | zpat | 
			  
				|  Posted: Wed May 16, 2007 1:47 am    Post subject: |   |  | 
		
		  |  Jedi Council
 
 
 Joined: 19 May 2001Posts: 5867
 Location: UK
 
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				| MQ V6 now has channel data compression features as standard. It looks very easy to set up (much easier than writing message exits for example). 
 Channels will negotiate the best compatible compression available, so that if you connect V5 to V6 it will still work, but not compress the data.
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