MQ Monitoring agent is writing to the MQ Dead Letter Queue
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Product: WebSphere MQ monitoring agent (ITCAM)
This article also applies to MQ monitoring agent from APM V8.1.x product.
You have MQ monitoring agent running, and all looks good. Then you get a call from your MQ Admin team, they are concerned about many messages from ITCAM MQ monitoring agent ending up in the Dead Letter Queue (DLQ).
How is agent writing to the DLQ? How to resolve this problem? This is the topic of following discussion.
Cause of the problem:
A dead-letter queue (DLQ), sometimes referred to as an undelivered-message queue, is a holding queue for messages that cannot be delivered to their destination queues, for example because the queue does not exist, or because it is full.
The monitoring agent creates a dynamic queue name
Resolving the problem:
The dynamic queue KMQ.
The default value for MAXDEPTH in QMGR configuration is 5000. You can check this setting using runmqsc tool as follows:
There are two ways to increase the MAXDEPTH of the agent reply-queue as described below.
Option 1: To resolve the problem of messages in DLQ, increase the MAXDEPTH of the model queue as follows, and then restart the monitoring agent:
AMQ8008I: IBM MQ queue changed.
This should resolve the problem of MQ monitoring agent messages ending up in DLQ.
You may need to adjust the model queue MAXDEPTH setting further. You can try setting to 50000 and reduce from there to get to an optimum value for your queue manager activity and agent configuration.
Option 2: The MQ Admin team may not agree to increasing the MAXDEPTH setting for the SYST
Use following commands to create KMQ.
The agent will now use the
IBM MQ: Dead-letter queues
(The best practices link applies to distributed platform as well.)
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