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| sjclark1 |
 Posted: Wed Jun 22, 2011 5:03 am Post subject: Can Clustering Help This Scenario? |
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Apprentice
Joined: 06 Jan 2003
Posts: 35
Location: Scotland
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I've just read this overview of clustering:
http://www.capitalware.biz/dl/docs/MQ_Clustering_101.pdf
I understand if we used clustering then we could *put* messages for some queues to server#1 and they could magically appear on server#2, provided the local queue defintion existed on the MQ on server#2 and not server#1.
My Question is: Does clustering also work for GETTING messages? i.e. a message is sitting on an output queue on server#1. An app wants to get this message but its DNS is pointing at server#2. If the app tries to retrieve a message from server#2 (when server#2 does NOT have a local defintion of the queue) then does clustering magically retrieve this message from server#1?
I think the answer is 'no' and that clustering is only used put PUTTING messages rather than GETTING messages, but wondered if some bright spark could enlighten me? |
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| mqjeff |
| Posted: Wed Jun 22, 2011 5:09 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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There is no method at all in MQ to GET a message from a queue that is NOT a QLOCAL on the queue manager that you are connected to.
If Roger's little missive didn't make that clear, it's probably not entirely his fault, as the MQ Cluster manual is probably not that clear on this point either. |
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| shashivarungupta |
| Posted: Wed Jun 22, 2011 6:27 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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You can Remotely PUT But can not Remotely GET messages from a queue, in MQ Cluster.
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*Life will beat you down, you need to decide to fight back or leave it. |
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| sjclark1 |
| Posted: Wed Jun 22, 2011 6:34 am Post subject: |
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Apprentice
Joined: 06 Jan 2003
Posts: 35
Location: Scotland
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| Thanks both of you, just what I thought but wanted to double check it didn't explicitly say. |
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| mqjeff |
| Posted: Wed Jun 22, 2011 6:45 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| shashivarungupta wrote: |
You can Remotely PUT But can not Remotely GET messages from a queue, in MQ Cluster. |
In ANY kind of MQ topology, you CANNOT remotely GET AT ALL, cluster or no cluster.
Even a zOS Shared Queue is *not* a Remote Get, because it's a local instance of the shared queue you are Getting from. |
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| mvic |
| Posted: Wed Jun 22, 2011 10:06 am Post subject: Re: Can Clustering Help This Scenario? |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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My esteemed colleagues are correct in what they say.
But why is the question arising? Why have the message sitting on an output queue where your client is not connected? Do you instead need to complete the journey, ie. have the message routed back to where the client is?
(I could have misunderstood.)  |
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| bruce2359 |
| Posted: Wed Jun 22, 2011 10:21 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| shashivarungupta wrote: |
You can Remotely PUT But can not Remotely GET messages from a queue, in MQ Cluster. |
You can put to a queue anywhere in your network; but you can only get a message from a local queue. It makes no difference if it's a cluster queue.
PUT GLOBAL; GET LOCAL.
PUT GLOBAL; GET LOCAL.
PUT GLOBAL; GET LOCAL.
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Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| shashivarungupta |
| Posted: Wed Jun 22, 2011 10:29 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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| bruce2359 wrote: |
| shashivarungupta wrote: |
You can Remotely PUT But can not Remotely GET messages from a queue, in MQ Cluster. |
You can put to a queue anywhere in your network; but you can only get a message from a local queue. It makes no difference if it's a cluster queue.
PUT GLOBAL; GET LOCAL.
PUT GLOBAL; GET LOCAL.
PUT GLOBAL; GET LOCAL. |
Got it.
I never disagreed on that !! 
*It was a talk about MQ Cluster, so I've mentioned it in hurry, though I shouldn't have !
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| shashivarungupta |
| Posted: Wed Jun 22, 2011 10:41 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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I think you have got your fire gun repaired !  
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| mqjeff |
| Posted: Wed Jun 22, 2011 10:46 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| shashivarungupta wrote: |
| I never disagreed on that !! |
we know that.
We're just stressing the point for future readers. |
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| bruce2359 |
| Posted: Wed Jun 22, 2011 10:51 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| shashivarungupta wrote: |
| I think you have got your fire gun repaired ! |
Not at all.
I strive for clarity. Mentioning cluster queues in this way might lead a reader to presume that cluster queues are somehow treated differently in this very basic mq function: PUT GLOBAL, GET LOCAL.
_________________
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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| shashivarungupta |
| Posted: Wed Jun 22, 2011 11:03 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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| mqjeff wrote: |
| shashivarungupta wrote: |
| I never disagreed on that !! |
we know that.
We're just stressing the point for future readers. |
Okey... that point was already noticed and being clarified by you... before bruce2359 made another same redundant point !!
Though thanks for making clear and emphasizing upon that point, for furture readers.
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| bruce2359 |
| Posted: Wed Jun 22, 2011 12:38 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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shashivarungupta:
I don't take your posts personally. Please don't take my posts personally. My posts are meant to be taken professionally.
I never intend my posts to be personal attacks; and I expect that others posting here don't intend personal attacks either.
Often, as I'm typing a post, someone will post pretty much what I'm typing. I won't know this until I click on Submit.
_________________
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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| shashivarungupta |
| Posted: Wed Jun 22, 2011 12:48 pm 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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| bruce2359 wrote: |
shashivarungupta:
I don't take your posts personally. Please don't take my posts personally. My posts are meant to be taken professionally.
I never intend my posts to be personal attacks; and I expect that others posting here don't intend personal attacks either.
Often, as I'm typing a post, someone will post pretty much what I'm typing. I won't know this until I click on Submit. |
I'm learning professionally from you and all other senior Members & Moderators, all the times.
This process of learning is On. I'm glad as I'm talking/sharing/learning with so many intelligent people here. 
Have a good one ! 
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*Life will beat you down, you need to decide to fight back or leave it. |
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| sjclark1 |
| Posted: Thu Jun 23, 2011 12:03 pm Post subject: Re: Can Clustering Help This Scenario? |
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Apprentice
Joined: 06 Jan 2003
Posts: 35
Location: Scotland
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| mvic wrote: |
But why is the question arising? Why have the message sitting on an output queue where your client is not connected? Do you instead need to complete the journey, ie. have the message routed back to where the client is?
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There is a long story involved which I started to type but it was getting too long. External systems connect to our QM, to send us messages, which we route / transform and send to queues for some other apps to retrieve.
We have 3 servers (with 1 QM each) but every external app is connected to server#1's QM as that's where the shared MQ 'PUT' component runs. This means we have a huge volume of connections to one node, which isn't very clever as the other 2 QMs are pretty much redundant.
Clustering would enable us to PUT messages to server#2, even though the single shared MQ sender component runs on server#1. So some clients could connect to server#2 and find their messages there, which balances the load.
I just wanted to double check if the same sort of thing could be used for GETTING messages, i.e. our own internal MQ listeners could run on server#2 (i.e. connect to QM#2) and yet magically retrieve messages from server#1. But I now understand this isn't possible because my new mantra is "PUT GLOBAL; GET LOCAL".
Last edited by sjclark1 on Thu Jun 23, 2011 12:34 pm; edited 2 times in total |
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