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| Rahul999 |
 Posted: Wed Jul 28, 2010 6:47 am Post subject: MQ Weird Problem regarding the "q" file size |
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Centurion
Joined: 14 Mar 2007
Posts: 134
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Hi All,
Today I faced a issue(which looks weird to me). What happened on our AIX server was (where we are running Websphere MQ 6.0.2.8, the /var/mqm file system became almost full.
To clean up the file system, I tried to look for files bigger than 50 MB in that file system and found that a 'q' file present at the below location is of size approx 75MB.
/var/mqm/qmgrs/BROKER1/queues/LOG.QUEUE/q
I was expecting a huge number of messages in this queue but when I checked the depth of this queue, it shows CURDEPTH as '0', so I went back to the location again and found that the file size is still that big.
what could be the reason, I understand that there were lot of activities was going on so that queue might have reached to that size, but when there are no messages(all got processed), then why the q file size stays so big.
Any observation folks?
Regards,
Last edited by Rahul999 on Wed Jul 28, 2010 6:56 am; edited 1 time in total |
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| exerk |
| Posted: Wed Jul 28, 2010 6:53 am Post subject: |
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Jedi Council
Joined: 02 Nov 2006
Posts: 6339
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I believe there has been previous discussion on the board (somewhere) in regard to how/when a queue manager scavenges queue files, and shrinks them when necessary. Worth your while searching I think...
EDIT: And if your file system went nearly full, it suggests that your sizing is incorrect, so you should review it and grow the file system accordingly.
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It's puzzling, I don't think I've ever seen anything quite like this before...and it's hard to soar like an eagle when you're surrounded by turkeys. |
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| sumit |
| Posted: Wed Jul 28, 2010 8:20 am Post subject: |
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Partisan
Joined: 19 Jan 2006
Posts: 398
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Curdepth could be 0, but how about the uncom messages?
It could be that the messages are in uncommitted state and hence not getting reflected in curdepth.
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Regards
Sumit |
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| fjb_saper |
| Posted: Wed Jul 28, 2010 11:20 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20768
Location: LI,NY
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| sumit wrote: |
Curdepth could be 0, but how about the uncom messages?
It could be that the messages are in uncommitted state and hence not getting reflected in curdepth. |
Sorry but uncommitted messages are reflected in qdepth. They are just not in a getable state. 
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MQ & Broker admin |
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| fjb_saper |
| Posted: Wed Jul 28, 2010 11:22 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20768
Location: LI,NY
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| exerk wrote: |
I believe there has been previous discussion on the board (somewhere) in regard to how/when a queue manager scavenges queue files, and shrinks them when necessary. Worth your while searching I think...
EDIT: And if your file system went nearly full, it suggests that your sizing is incorrect, so you should review it and grow the file system accordingly. |
 MQ decides when it's time to shrink a file and it is obviously not when you expect it to. As a work around try putting a single message on the queue and then getting it. If you are lucky it might work...
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MQ & Broker admin |
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| sumit |
| Posted: Thu Jul 29, 2010 7:00 am Post subject: |
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Partisan
Joined: 19 Jan 2006
Posts: 398
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| fjb_saper wrote: |
| sumit wrote: |
Curdepth could be 0, but how about the uncom messages?
It could be that the messages are in uncommitted state and hence not getting reflected in curdepth. |
Sorry but uncommitted messages are reflected in qdepth. They are just not in a getable state. |
Yes, you are right. However, I was refering to a scenario like this
But now I am thinking if it can increase the q file size. 
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Regards
Sumit |
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| mvic |
| Posted: Sat Jul 31, 2010 2:09 pm Post subject: Re: MQ Weird Problem regarding the "q" file size |
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Jedi
Joined: 09 Mar 2004
Posts: 2080
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| Rahul999 wrote: |
/var/mqm file system became almost full.
To clean up the file system, I tried to look for files bigger than 50 MB in that file system and found that a 'q' file present at the below location is of size approx 75MB.
/var/mqm/qmgrs/BROKER1/queues/LOG.QUEUE/q |
You probably had 75 Mb of messages on that queue quite recently. They are all gone now, and the queue manager will shrink the file at a time of its choosing.
I searched the internet and found this IBM page which seems to contain relevant statements: http://www.ibm.com/support/docview.wss?rs=171&uid=swg21110841
By the way, one queue growing to 75 Mb should not be an unplanned event. I mean, it should not be allowed that this causes the filesystem to be full. I suggest you get more space allocated to allow proper headroom in case something similar happens again. |
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