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| banjar1 |
 Posted: Fri May 07, 2010 1:45 am Post subject: Automatic re-creation of deleted subscriptions? |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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Hi,
We are using MQ7.0.1.1 (on AIX) with built-in Publish and Subscribe mechanism.
I noticed interesting thing: two days ago I deleted a bunch of subscriptions (using DELETE SUB SUBID( subscription_id ) ). I checked for them with DIS SUB and didn't find them. But today this QM hung due to running out of log space and I had to stop it (I used endmqm -i) to increase the number of available log files. After restarting (normal strmqm) all the deleted subscriptions were there again! Since we save QM configuration daily (using saveqmgr.aix binary) I checked there again and didn't find them there.
Any explanation? |
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| fjb_saper |
| Posted: Fri May 07, 2010 3:07 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Did you set up the pub/sub maintenance jobs? 
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MQ & Broker admin |
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| banjar1 |
| Posted: Fri May 07, 2010 3:09 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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| "Maintenance jobs"? what's that? |
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| fjb_saper |
| Posted: Fri May 07, 2010 3:10 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| banjar1 wrote: |
| "Maintenance jobs"? what's that? |
Have you read the pub/sub manual?
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MQ & Broker admin |
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| banjar1 |
| Posted: Fri May 07, 2010 3:13 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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| Yes and no. I found what I needed inside, but didn't read it page after page. |
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| banjar1 |
| Posted: Fri May 07, 2010 3:27 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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Perhaps I should also mention we use P&S in very simple way: publications are done by a shell script using 'q' binary (triggerred whenever a message arrives on a queue) and the only subscribers are some remote queues on the same QM. So, all I need to do to add new subscriber is creating new remote queue and defining new subscription using mqsc commands. I though dleteing such subscription would remove them for good from QM - but apparentyl I need to do something more to avoid theri "ressurection" after QM restart, right?
I'm reading "MQ P&S User's Guide" again but can't find anything on that. |
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| mqjeff |
| Posted: Fri May 07, 2010 4:21 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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No.
Deleting a subscription using MQSC should be a final operation. Nothing inside the queue manager should recreate that subscription, to the best of my knowledge - unless of course it's an internal subscription.
It's at least somewhat likely that the apps reading the subscription message have done something to register themselves again.
Especially if the subscriptions are not durable subscriptions. The doc on DELETE SUB explicitly says it will delete durable subscriptions. |
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| banjar1 |
| Posted: Fri May 07, 2010 4:38 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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No, the apps can't do anything like that - they simply MQGET messages from Local Queues on another QMs. We use P&S to multiply messages: they arrive on Broker QM to a Local Queue which triggers a script with 'q -Ts...' to publish them to related STREAM queue. Set of ADMIN-defined subscriptions makes sure they are then delivered to Remote Queues - and they leave Broker QM at this moment.
All definitions and administration is done using MQSC commands, incl. creation and deletion of SUBscriptions, TOPICs, STREAM-queues etc etc.
It has been working fine since about a year, with several restarts - and we have never observed the subcriptions to be re-created automatically before. It was, however, the first time we restarted it after applying patch 7.0.1.1. |
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| mqjeff |
| Posted: Fri May 07, 2010 5:23 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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To the best of my knowledge, nothing the QM does should have recreated any subscriptions that were deleted, even after an upgrade.
If the app teams didn't have any mechanism to recreate these subscriptions, then someone on the admin team did.
Perhaps they re-applied a backup from ms03 when you weren't looking during the upgrade process. |
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| banjar1 |
| Posted: Fri May 07, 2010 5:30 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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1. The re-creation didn't happen during the upgrade, it happened today, a couple of weeks after the upgrade itself. It was the first re-start after the one caused by upgrade - and I noticed the re-created subscriptions immediately.
2. I know for sure the application reading the messages does not connect to Broker QM and doesn't have any P&S capabilities, just pure and simple MQGET.
3. I'm the "admin team" here 
Thanks for re-assuring. It means we need to do another restart to check if the subscriptions are re-created again - and open a PMR if they are. |
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| bruce2359 |
| Posted: Fri May 07, 2010 5:38 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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| Quote: |
| ...and I noticed the re-created subscriptions immediately. |
I'm curious. How did you notice the re-created subscriptions immediately?
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Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| banjar1 |
| Posted: Fri May 07, 2010 5:43 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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| Well, the restart was caused by QM running out of log space - and that I noticed when no messages were published, but many were stored on receiving queues. After the restart publishing started to work again and suddenly some queues, that were not supposed to get messages anymore (corresponding channels were stopped and their subscriptions deleted; there has been no activity on them for the last two days) were running full. |
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| bruce2359 |
| Posted: Fri May 07, 2010 5:57 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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| Quote: |
| restart was caused by QM running out of log space |
Ah... new information.
I'd guess that when you restarted the qmgr, it replayed the logs (as described in the System Admin manuals), and brought the qmgr back to the last point of consistency - which included restoring messages (pubs and subs) to queues.
To test this theory, do some pubs and subs, then delete them; then end the qmgr normally; then restart.
_________________
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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| banjar1 |
| Posted: Fri May 07, 2010 6:02 am Post subject: |
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Acolyte
Joined: 29 Nov 2006
Posts: 54
Location: FRA
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1. I mentioned the reason for the restart in original post.
2. The subscriptions were delted two days ago... All messages from these queues were transmitted to their destinations then - and the corresponding channels were stopped after that (STOP CHL)
3. The SUB objects deleted two days ago were there again right after the restart of QM today - and because of them the queues were filled with messages. |
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| nallabalu |
| Posted: Fri May 07, 2010 6:06 am Post subject: |
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Novice
Joined: 29 Mar 2005
Posts: 19
Location: Long Island, NY
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| I am sure, its your application recreating the durable subscriptions. Stop your app's connecting the Qmgr, delete the subscriptions and restart your Qmgr(don't start your App's). you will see no sub's created after the restart, but it is when your app's connect your QM all the durable subscriptions are recreated automatically. Please Check with your App team once again. |
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