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| MQMB&WAS |
 Posted: Thu Jul 09, 2020 10:44 am Post subject: Long running transaction rolled forward |
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Centurion
Joined: 12 Jun 2016
Posts: 130
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Hello all,
When a qmgr rolls forward a long running transaction to free up space, does the client application see any mqrc error codes?
Thanks |
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| bruce2359 |
| Posted: Thu Jul 09, 2020 2:22 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9442
Location: US: west coast, almost. Otherwise, enroute.
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What would an app do or not do in such a situation?
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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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| gbaddeley |
| Posted: Thu Jul 09, 2020 3:44 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2527
Location: Melbourne, Australia
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AFAIK, MQ does not roll forward. It either commits or backs out (rolls back) transactions. Backed out UOW results in MQ messages that were got under syncpoint to become eligible to be got by the app again. Backed out puts result in no message being hardened to a queue.
If the app receives a MQRC_BACKED_OUT from MQGET or MQPUT or MQPUT1, the app should proceed to backout all resources in the transaction.
_________________
Glenn |
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| fjb_saper |
| Posted: Thu Jul 09, 2020 10:00 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20729
Location: LI,NY
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I'm going out on a limb here and expect that the original poster was talking about linear logging. So if you have a message on a queue that is long lived, it may happen that the log for that message needs to be rolled forward. This would happen behind the scene and be completely transparent to the user.
If you do not roll forward the risk is that you will exhaust your log space and the queue manager will stop. Have fun 
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MQ & Broker admin |
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| MQMB&WAS |
| Posted: Fri Jul 10, 2020 12:39 am Post subject: |
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Centurion
Joined: 12 Jun 2016
Posts: 130
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| fjb_saper wrote: |
I'm going out on a limb here and expect that the original poster was talking about linear logging. So if you have a message on a queue that is long lived, it may happen that the log for that message needs to be rolled forward. This would happen behind the scene and be completely transparent to the user.
If you do not roll forward the risk is that you will exhaust your log space and the queue manager will stop. Have fun |
Yes, linear logging.
Application reported they were facing mqtc host nit available errors and at the same time mq was logging this log forward messages. So just wondering if this log forwading would cause those mqrc host not available errors at the client. |
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| bruce2359 |
| Posted: Fri Jul 10, 2020 3:12 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9442
Location: US: west coast, almost. Otherwise, enroute.
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| MQMB&WAS wrote: |
Application reported they were facing mqtc host not available errors and at the same time mq was logging this log forward messages. So just wondering if this log forwading would cause those mqrc host not available errors at the client. |
What log forward messages? Please post the entire error message here.
_________________
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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| tczielke |
| Posted: Fri Jul 10, 2020 4:33 am Post subject: |
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Guardian
Joined: 08 Jul 2010
Posts: 941
Location: Illinois, USA
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| gbaddeley |
| Posted: Sun Jul 12, 2020 3:22 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2527
Location: Melbourne, Australia
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| MQMB&WAS wrote: |
Yes, linear logging.
Application reported they were facing mqtc host nit available errors and at the same time mq was logging this log forward messages. So just wondering if this log forwading would cause those mqrc host not available errors at the client. |
"host not available" is usually a network issue, or a resource shortage issue on the host. The "log forward" activity may be another symptom of this underlying issue. Can you provide details of what was in the MQ error log?
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Glenn |
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