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| Trigger first issue in sysplex environment |
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| sami.stormrage |
 Posted: Mon Jul 28, 2008 3:09 am Post subject: |
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Disciple
Joined: 25 Jun 2008
Posts: 186
Location: Bangalore/Singapore
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U must define ur Q with trigger "Every" and the InitQ as a shared Q/private Q. First thing that happens is tht the app Qmgr will nominate a Qmgr to generate a Trigger message to be put on the Init Q. And a single application will be started on any on the Qmgrs in the sysplex. Or the application will be started on the nominated Qmgr if its a private InitQ.
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Last edited by sami.stormrage on Fri Aug 01, 2008 9:41 am; edited 1 time in total |
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| bruce2359 |
| Posted: Mon Jul 28, 2008 4:09 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9471
Location: US: west coast, almost. Otherwise, enroute.
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| Quote: |
| We expected that no more then one task will be active in parallel, cross lpars. |
Are you saying that when one message arrived in the shared queue that two takss in different cics (one task in each) were launched to consume the single message?
Or are you saying that multiple messages arrived, and that multiple cics tasks (wherever) were launched?
Does your application expect to consume as many messages as are available in the shared queue? MQGET until 2033? (That's more tha 20 years from now, isn't it?)
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| hopsala |
| Posted: Fri Aug 01, 2008 9:52 am Post subject: |
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Guardian
Joined: 24 Sep 2004
Posts: 960
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A client just asked me about this, so I'm reviving this (not so) old thread to add something I found in the redbook "WebSphere MQ in a zOS Parallel Sysplex Environment " (sg246864) page 231:
| Quote: |
| Note: For TRIGTYPE=FIRST, the choice of a shared or non-shared initiation queue is not important. In both cases, a trigger message will be generated for each instance of CKTI. |
(In the example given, each QM in the group has one CKTI running against the INITQ)
This is hardly a full explanation (ibm lit.. sigh), but it does add something to the debate. However, it is unclear to me whether they mean that if you have two CKTI's on the same QM two trigger message will be created or not.
Concerning two CKTI's on two different QM's, my own instincts point to the same direction as Peter's - when an applicationQ is shared, regardless of whether the INITQ is shared or not, a trigger message is generated for each QM in which the INITQ is open and the applicationQ is not open for input. Otherwise, every MQ design pattern I know turns to s**t.
Does anyone have any hands-on experience with this? |
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| sami.stormrage |
| Posted: Fri Aug 01, 2008 12:23 pm Post subject: |
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Disciple
Joined: 25 Jun 2008
Posts: 186
Location: Bangalore/Singapore
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| Quote: |
| when an applicationQ is shared, regardless of whether the INITQ is shared or not, a trigger message is generated for each QM in which the INITQ is open and the applicationQ is not open for input. Otherwise, every MQ design pattern I know turns to s**t. |
Nope.. if a Init Q is shared only a single trigger message is genarated and put to the shared InitQ, after which, there will be a race b/w the trigger monitors running to pickup the message... which is not good either...
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| bob_buxton |
| Posted: Fri Aug 01, 2008 12:40 pm Post subject: |
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Master
Joined: 23 Aug 2001
Posts: 266
Location: England
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| hopsala wrote: |
Concerning two CKTI's on two different QM's, my own instincts point to the same direction as Peter's - when an applicationQ is shared, regardless of whether the INITQ is shared or not, a trigger message is generated for each QM in which the INITQ is open and the applicationQ is not open for input. Otherwise, every MQ design pattern I know turns to s**t.
Does anyone have any hands-on experience with this? |
You are correct, For trigger type First or Depth, one trigger message is generated per queue manager where initiation queue is open and application queue is not open.
If you have a shared initiation queue it is possible that the same CKTI could get all trigger messages which is not so good for work load balancing. So a cloned initiation queue, QSGDISP(GROUP), is better.
If you have more than one CKTI connected to the same queue manager only one message is generated by the queue manager and only one CKTI will get the message.
With trigger type every only one trigger message is generated regardless of the number of Queue managers. So in this case a shared initiation queue allows the workload to be balanced but it is not essential since the work of generating trigger messages is spread across the sysplex.
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Bob Buxton
Ex-Websphere MQ Development |
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