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| Logging Question |
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| Gideon |
 Posted: Wed Dec 30, 2009 1:06 pm Post subject: Logging Question |
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Chevalier
Joined: 18 Aug 2009
Posts: 403
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I installed WMB 7 on AIX (works great)
I want to optimize it, by putting any logging directories onto a RAID
I did this for the WMQ, and it works very well.
However, I looked under both the opt and var directories, and did not find any log directories.
Is this because WMB relies completely on WMQ, and the logging is essentially done there (on a transactional basis, as opposed to MQSIstart and MQSIstop messages)
Are there any directories within the mqsi space that I should move to a raid ?
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| smdavies99 |
| Posted: Wed Dec 30, 2009 1:54 pm Post subject: |
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Jedi Council
Joined: 10 Feb 2003
Posts: 6076
Location: Somewhere over the Rainbow this side of Never-never land.
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Could you elaborate as to what you understand about WMB Logging and how you think it differs from or is the same as WMQ logging.
Whilst broker dows use WMQ as a transport for deploying flows etc, it can use many other protocols & transports in actual message flows. A flow can do 'stuff' without ever involving WMQ so why would it use something like WMQ Logging?
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Every time you reinvent the wheel the more square it gets (anon). If in doubt think and investigate before you ask silly questions. |
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| Gideon |
| Posted: Thu Dec 31, 2009 11:13 am Post subject: |
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Chevalier
Joined: 18 Aug 2009
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All of my flows use WMQ as the input and the output.
WMQ provides the logging for the Persistent messaging.
Whyat I am trying to understand is what logging WMB provides, if any, as messages go through a flow into COMPUTE and FILTER nodes or within a flow (if any). Since problem messages go through the DLQ, I do not think WMB will log any of these message flow instances, because if they are properly written, the message will always end up on a WMQ queue of some sort
However, what about transacted messages, if they flow through a message flow will they be logged by WMB (again, I dont think so, but wanted to ask if my thinking on this is correct)
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| zpat |
| Posted: Thu Dec 31, 2009 11:31 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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If a message flow is transactional, it means the MQGET/MQPUT is using SYNCPOINT, that's all (unless databases are also being updated in the flow).
Syncpointed gets remain on the queue until committed, the MQ log will have a pointer to the message, but not the data.
Syncpointed puts are written to the MQ log. There is no WMB log as such unless coded by the application in the flow. |
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| Vitor |
| Posted: Thu Dec 31, 2009 11:36 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| Gideon wrote: |
| Since problem messages go through the DLQ, |
No they don't. They go to the backout queue (if defined) or back on the original queue. There are many discussions of poison messages in the forum.
| Gideon wrote: |
| I do not think WMB will log any of these message flow instances, because if they are properly written, the message will always end up on a WMQ queue of some sort |
If by properly written you mean "don't delete the message" you're right. The message will always end up somewhere, and if your flows are exclusively using WMQ that place will be a queue.
| Gideon wrote: |
| However, what about transacted messages, if they flow through a message flow will they be logged by WMB (again, I dont think so, but wanted to ask if my thinking on this is correct) |
What about transacted messages? WMB is simply an application using WMQ in this context. Does a C application using a database have specific logging for a transaction, or does it simply issue commit or rollback according to need? Why would WMB be doing anything different?
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Insanity is the best defence. |
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| Gideon |
| Posted: Thu Dec 31, 2009 1:34 pm Post subject: |
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Chevalier
Joined: 18 Aug 2009
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| fjb_saper |
| Posted: Thu Dec 31, 2009 6:13 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| Vitor wrote: |
| No they don't. They go to the backout queue (if defined) or back on the original queue. There are many discussions of poison messages in the forum. |
I am not 100% sure there, that you don't need to qualify. If a Backout Threshold is defined but no BO Queue is defined, I believe the message gets put by the broker to the DLQ with a 65K type reason code...
If no BO threshold is defined it goes back to the input queue and you have a poison message... 
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| smdavies99 |
| Posted: Thu Dec 31, 2009 9:32 pm Post subject: |
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Jedi Council
Joined: 10 Feb 2003
Posts: 6076
Location: Somewhere over the Rainbow this side of Never-never land.
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As has been documented many times on this forum, unless you setup the underlying WMQ infrasructure properly, you can get into a lot of trouble.
One more points about the DLQ
The existence of a DLQ is entirely OPTIONAL. I know of sites where the use of a DLQ is absolutely forbidden.
Personally, I treat the DLQ as a place of last resort to avoid a poison message.
However you can still get a poison message if a whole number of things happen
IF cond a
If cond b
if cond c
Something like the following:-
If your flow rolls back a message into a BOQ that is FULL and the DLQ is FULL and the Message is PERSISTANT then you get a poison message. This is because WMQ won't throw away PERSISTENT Messages.
However this is all getting away from your original question about Broker Logging.
Unless you put stuff in yourself there is basically none. In a high performace system this is mostly regarded as an unneccessary overhead. There are times though that some form message tracing can be useful and usertrace can easily be switched on for a particular flow. Please bear in mind that this in itself has its own limitations (eg a circular buffer) and is not the be all and end all of message logging.
_________________
WMQ User since 1999
MQSI/WBI/WMB/'Thingy' User since 2002
Linux user since 1995
Every time you reinvent the wheel the more square it gets (anon). If in doubt think and investigate before you ask silly questions. |
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