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| venkataramanan |
 Posted: Tue Oct 15, 2002 6:07 pm Post subject: Global unit of work??????????? |
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Apprentice
Joined: 18 Sep 2002
Posts: 47
Location: Chennai, India
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 Can anybody please tell me what is GLOBAL UNIT OF WORK in wmqsi. Actually this question was asked when i went for an interview.
Thanks
regards
venkat |
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| kolban |
| Posted: Tue Oct 15, 2002 7:09 pm Post subject: |
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Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
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I would say that a global unit of work is transactional activity against multiple resources (eg database, MQ queues, another database) that should be included in the same transaction. All the activities will either be commited or rolledback as a unit.
Work performed against a single resource that is commited or rolledback in insolation, I would call a local unit of work. |
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| venkataramanan |
| Posted: Wed Oct 16, 2002 12:12 am Post subject: |
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Apprentice
Joined: 18 Sep 2002
Posts: 47
Location: Chennai, India
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Hmmmmm thank you kolban really a nice explanation. hereafter i will tell the same answer if any question is asked in the interviews.
But could be little bit precise regarding the transaction. you said "All the activities will either be commited or rolledback as a unit" i will be happy if you tell me more explanation about this part.
thanks
regards
venkat |
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| kolban |
| Posted: Wed Oct 16, 2002 10:34 am Post subject: |
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Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
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| When messages are put/get from a queue or rows added, deleted or updated in a table, these are changes to a resource. If the changes are to be made permanent, this is called "commiting"the changes. If the changes or activities are to be "undone", these are called being "rolled back" |
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| venkataramanan |
| Posted: Wed Oct 16, 2002 5:18 pm Post subject: |
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Apprentice
Joined: 18 Sep 2002
Posts: 47
Location: Chennai, India
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Thank you kolban really thanks for your clarification.
with regards
venkat |
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| mmarq |
| Posted: Thu Oct 17, 2002 5:20 am Post subject: global unit of work |
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Acolyte
Joined: 19 Sep 2002
Posts: 74
Location: Newton, MA
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It is also leveraging the XA protocol which specifies a bidirectional interface between a transaction manager and its resource manager. So across recoverable resources in a distributed environment, you can get a single transaction manager to coordinate a unit of work across its resource managers.
In MQSI (in the implementation we are doing) this means that MQSeries is assigned the duty of transaction manager and our database and MQSI are resource managers. The database you are using has to be able to support XA to do this. DB2 does and that is what we are using. I believe Oracle and Sybase do as well.
It requires some careful configuration across the database(s), MQSI and MQSeries to make this work. This implementation is known as a globally coordinated unit of work in MQSI. THere are variations and caveats to this so you'll want to read up in MQSI, MQSeries and your database manuals for this support.
Hope this helps!
-Melissa
NerveWire, Inc.
_________________
M Marquis |
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