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| jerrydBrowser |
 Posted: Mon Feb 22, 2010 6:55 pm Post subject: What is Listener in MQ. |
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Newbie
Joined: 22 Feb 2010
Posts: 4
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Hi,
I am a newbie in MQ. While playing around MQ V7.0.1, I don’t think that I fully understand the listener in MQ. I hope that I can get some clarification via your help.
Based on the MQ InfoCenter, “Listener objects are used to accept incoming network requests from remote queue managers, or client applications. Once accepted, a listener starts the associated receiver or server connection channels to allow the queue manager to receive messages”.
If my interpretation is correct, does it mean that there is a one-to-one association between channel and listener?
I have noticed that when I created a new queue manager using: “crtmqm” command, the system will have a listener called “SYSTEM.DEFAULT.LISTENER.TCP” created automatically. What channel is this listener associated with?
I also have used MQ Explorer to create a new listener ,“test1”. So now my system has 2 listeners:
display listener(*)
AMQ8630: Display listener information details.
LISTENER(SYSTEM.DEFAULT.LISTENER.TCP)
AMQ8630: Display listener information details.
LISTENER(test1)
If there is a request pick up by “test1” listener, what channel is going to be associated with such request?
Thanks |
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| Vitor |
| Posted: Mon Feb 22, 2010 7:18 pm Post subject: Re: What is Listener in MQ. |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| jerrydBrowser wrote: |
| does it mean that there is a one-to-one association between channel and listener? |
| jerrydBrowser wrote: |
| I have noticed that when I created a new queue manager using: “crtmqm” command, the system will have a listener called “SYSTEM.DEFAULT.LISTENER.TCP” created automatically. What channel is this listener associated with? |
None. See above.
| jerrydBrowser wrote: |
| If there is a request pick up by “test1” listener, what channel is going to be associated with such request? |
None. See above. Channels match with their pairs.
You'll find the Intercommunication manual an invaluable source of information. You might also find the MQ Primer useful.
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Honesty is the best policy.
Insanity is the best defence. |
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| shashivarungupta |
| Posted: Tue Feb 23, 2010 12:54 am Post subject: |
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Grand Master
Joined: 24 Feb 2009
Posts: 1343
Location: Floating in space on a round rock.
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(In addition ) Also read about the runmqlsr and amqcrsta processes in detail.
Have fun !
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| mvic |
| Posted: Tue Feb 23, 2010 1:33 am Post subject: |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| shashivarungupta wrote: |
| (In addition ) Also read about the runmqlsr and amqcrsta processes in detail. |
Both of these are advanced topics for someone learning what a listener is.
Good advice for later study though 
| jerrydBrowser wrote: |
If my interpretation is correct, does it mean that there is a one-to-one association between channel and listener?
I have noticed that when I created a new queue manager using: “crtmqm” command, the system will have a listener called “SYSTEM.DEFAULT.LISTENER.TCP” created automatically. What channel is this listener associated with? |
A few basics:
A listener is a part of MQ that starts and "listens" on a TCP/IP port, and begins a channel when an inbound request arrives on that port.
If using a listener "object" you must start it. When you do so, you should then see a runmqlsr process running.
Any object named SYSTEM.DEFAULT.* is intended to be a template, and an example that might be used for your own objects. It's not advisable to alter them and use them as part of your running MQ system.
A channel is a very separate type of thing from a listener. A listener is involved in starting up an instance of a channel, but there is no general mapping relationship between specific channels and listeners apart from this. |
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| shashivarungupta |
| Posted: Tue Feb 23, 2010 1:53 am Post subject: |
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Grand Master
Joined: 24 Feb 2009
Posts: 1343
Location: Floating in space on a round rock.
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| mvic wrote: |
...If using a listener "object" you must start it. When you do so, you should then see a runmqlsr process running.
A channel is a very separate type of thing from a listener. A listener is involved in starting up an instance of a channel, but there is no general mapping relationship between specific channels and listeners apart from this. |
Start the listener and then look at the runmqlsr process status., if the person doesn't know anything about the runmqlsr then why he should look into that ..just for the sake of the steps !!! 
I believe .. if he/she knows what is runmqlsr and what it does then it would be more understandable and realistic for him/her. Anyways its 'jerrydBrowser' who gonnu decide what to do and what not to do. 
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Last edited by shashivarungupta on Tue Feb 23, 2010 2:07 am; edited 1 time in total |
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| exerk |
| Posted: Tue Feb 23, 2010 2:05 am Post subject: |
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Jedi Council
Joined: 02 Nov 2006
Posts: 6339
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| shashivarungupta wrote: |
| mvic wrote: |
...If using a listener "object" you must start it. When you do so, you should then see a runmqlsr process running.
A channel is a very separate type of thing from a listener. A listener is involved in starting up an instance of a channel, but there is no general mapping relationship between specific channels and listeners apart from this. |
Start the listener and then look at the runmqlsr process status., if the person doesn't know anything about the runmqlsr then why he should look into that ..just for the sake of the steps !!!
I believe .. if he/she knows what is runmqlsr and what it does then it would be more understandable and realistic for him/her.
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When a Listener OBJECT is created, just what do you think it does in the background? Execute the runmqlsr command by any chance? Which is why I believe mvic suggested checking the object once started. Statements such as...
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| "...if he/she knows what is runmqlsr and what it does then it would be more understandable and realistic for him/her. ..." |
...confuse me as to what exactly you mean, let alone how confusing it must be for someone who is just starting out with WMQ.
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| shashivarungupta |
| Posted: Tue Feb 23, 2010 2:41 am Post subject: |
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Grand Master
Joined: 24 Feb 2009
Posts: 1343
Location: Floating in space on a round rock.
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| exerk wrote: |
| Quote: |
| "...if he/she knows what is runmqlsr and what it does then it would be more understandable and realistic for him/her. ..." |
...confuse me as to what exactly you mean, let alone how confusing it must be for someone who is just starting out with WMQ. |
I meant to say.. read about the basics of listener..basics of mq.. then ofcourse go for runmqlsr and amqcrsta that are related to listener topic .. don't miss that. 
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| jerrydBrowser |
| Posted: Thu Mar 04, 2010 7:19 am Post subject: |
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Newbie
Joined: 22 Feb 2010
Posts: 4
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| Thanks alll for the great information. I will go through those information you mentioned. |
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