I have seen this when the load on the queue manager/server is at a high
level because of the instances of the applications. When running a number
of instances I have seen a potential possibility of a failure. Especially
in a MCONN, MQOPEN, MQPUT, MQCLOSE, MQDISC. Also, depending on whether the
instances are threads or process there could be an issue when each thread
is doing a connection. Although its rare I have seen more problems with
processes than threads. As for it stating a 'create object error' I don't
recall getting that error, but then again it has been a while since I put a
system under duress. One option you mention is a positive one. The second
is to stagger each instance of an app, unless there is an actual need to
create 50 instances of the application. Another is to verify that you have
configured your client instances allowed for the queue manager.
Unless the applications require a constant connection what you may want to
do is create a pool of connections via a thread pool. It's simple, well
not for everyone, and based on the number of instances required they can
use the existing connections or if required additional connections within
the pool can be made.
One other suggestion is to put a timestamp before the MQCONN and one at
MQDISC. Kick off 20-50 instances of the application at once and see where
the delay is. If the applications are in a wait state to long it will
actually fail. That I do know because I have reproduced that a number of
times when doing high volume/client connections for WMQ.
This is a bugger to track down, but you may need to try different
configurations in order to determine the best route for application
process, system load, thread or process, and so forth.
Chris
|---------+------------------------------->
| | "Faizel Sedick" |
| | <[EMAIL PROTECTED]|
| | RTHS.CO.ZA> |
| | Sent by: "MQSeries |
| | List" |
| | <[EMAIL PROTECTED]|
| | C.AT> |
| | |
| | |
| | 01/23/2004 09:01 AM |
| | Please respond to |
| | "MQSeries List" |
| | |
|---------+------------------------------->
>------------------------------------------------------------------------------------------------------------------------------|
|
|
| To: [EMAIL PROTECTED]
|
| cc:
|
| Subject: Re: MQ connect errors
|
|
|
>------------------------------------------------------------------------------------------------------------------------------|
What I meant was that the actual app does not return MQ error codes. It
only states that the operation as a whole failed. When I try to recreate
the behaviour of the app using C code I get and error when doing
similtaneous MQCONN calls. ie I run 50 instances of an app so there is
potentialy 50 client connect calls which seems to generate the 2059 error.
Strange.
I have advised the application team not to do the continuous
connect/disconnect, but to stay connected as they do constantly write to
queues. That will fix their problem, but I am still can't accept this
behavour.
Cheers
Faizel
-----Original Message-----
From: Wyatt, T. Rob [mailto:[EMAIL PROTECTED]
Sent: Friday, 23 January 2004 15:56
To: [EMAIL PROTECTED]
Subject: Re: MQ connect errors
Hi there,
If your application does not use native MQI calls, then what is it?
All of the Java-based APIs supplied by IBM provide access to the MQ
Reason and Completion codes. I would think that the VB API would as
well but I don't use it and don't know.
Have you turned on all your event types? Sometimes this can be quite
helpful in discovering exactly what call failed and on which object.
Is that log entry from the host or the client?
-- T.Rob
-----Original Message-----
From: Faizel Sedick [mailto:[EMAIL PROTECTED]
Sent: Friday, January 23, 2004 4:07 AM
To: [EMAIL PROTECTED]
Subject: MQ connect errors
I am trying to simulate a problem we currently have in
production. This is what happens in production:
A client application on Windows starts 10 instances of itself,
connects to the same QM and the same queue at the same time. It
then puts a message and disconnects. Some of the instances fail
with a create object error. Its not native MQI calls and does
not return MQ error codes. I asume that the create object error
is either the creation of the queue or queue manager object, so
it either fails on MQOPEN or MQCONNECT call.
I tried to simulate this by running 20 apps that write 1000
messages to the same queue. First I create the loop around the
MQOPEN/PUT/CLOSE calls. ie the app stays connected to the queue
manager and then opens, puts and closes the 1000 times. This
finished with no errors. Then I put the loop around
MQCONN/OPEN/PUT/CLOSE/DISC and a few of them failed with 2059
errors.
The error logs just give the ususal "AMQ9202: Remote host
'w31873079 (10.36.137.79) (1414)' not available" error. There
is nothing in any other error logs or FDC files created.
Can anyone explain this. Does the listener just fail to start
up connections?
----------------------------------------------------------------------------
Faizel Sedick
Woolworths Integration
IBM MQSeries Certified Specialist, Developer & Solutions Expert
Email: [EMAIL PROTECTED]
Phone: +27 21 407 2452
Cell: +27 83 251 9361
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