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| MQ lost my message...well, not really. |
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| PeterPotkay |
 Posted: Wed Nov 07, 2007 11:30 am Post subject: MQ lost my message...well, not really. |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Let's get a list of all the reasons that can cause people to think that MQ lost their message:
The message expired
The message actually made it to the destination q and was consumed by the app.
The message was never a message, i.e. the app never got a good return code on its MQPUT.
The message was never a message, i.e. the app got a good return code on its MQPUT, but it used syncpoint and hasn't yet committed.
The message was non persistent (NP) travelling over a channel with a NPMSPEED of FAST and the channel barfed.
The message was NP and sitting on a q which is set to NPMCLASS(NORMAL) and the QM restarts.
The message was NP and sitting on a q which is set to NPMCLASS(HIGH) and the QM barfs.
The MQ Client did an MQGET, did not use syncpoint, and the client channel died after the QM finished the MQGET but before the client app got it.
The channel has not completed its batch yet, so the messages are "inside" the channel. Removed off of the XMITQ, but not available on the destination.
I know I'm missing some other scenario help me out guys
_________________
Peter Potkay
Keep Calm and MQ On
Last edited by PeterPotkay on Thu Nov 08, 2007 6:45 am; edited 1 time in total |
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| fjb_saper |
| Posted: Wed Nov 07, 2007 3:58 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| Quote: |
| The message actually made it to the destination q and was consumed by the app |
or the message actually made it to the destination q and was consumed by an unexpected consumer (not the intended app).
Make sure there is only one app consuming messages... Concurrency and multiple apps on the same queue without a selection by CorrelId (set by the qmgr not an app) can make it very difficult to determine which app actually got the message... 
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MQ & Broker admin |
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| bruce2359 |
| Posted: Wed Nov 07, 2007 4:32 pm Post subject: |
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Guest
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| One of my favorites, found by doing a trace: application code did not issue an MQPUT. Business logic (?) circumvented the MQPUT for some 'messages'. |
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| PeterPotkay |
| Posted: Wed Nov 07, 2007 5:56 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Another one:
The MQ Admin incorrectly commits a channel that is in doubt. The messages never made it to the receiving QM, but the resolve channel comand with the commit option tells the sending side MCA to assume they did. In this scenario the MQ Admin should have backed out the messages. Instead the commit caused all the messages in the channel's batch to get lost.
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Peter Potkay
Keep Calm and MQ On |
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