What is MQ error code 2268?

MQ error code 2268, known symbolically as MQRC_CLUSTER_PUT_INHIBITED, indicates that a queue manager attempted to place a message onto a queue but could not identify a valid destination because there is no local instance of the queue, and no cluster workload exit successfully chose an alternative queue instance within the cluster.

Understanding MQRC_CLUSTER_PUT_INHIBITED

When an application attempts to put a message to a clustered queue, IBM MQ performs a lookup to determine the best destination. Error code 2268 signifies a specific failure in this process. It means that the queue manager initiating the MQOPEN call for the put operation could not find a local definition of the target queue. Furthermore, even in a clustered environment designed to route messages to available instances, either:

• There was no cluster workload exit configured for the queue.
• A cluster workload exit was configured but it failed to select a suitable queue instance within the cluster to receive the message.

It's important to note that if a local instance of the queue did exist, the MQOPEN call would typically succeed, even if that local instance was put-inhibited (i.e., PUT(DISABLED)). The 2268 error specifically points to the absence of a local instance and the subsequent failure to route via the cluster.

Root Causes and Scenarios

This error typically arises from misconfigurations within an IBM MQ clustered environment. Here are common scenarios:

• Missing Local Queue Definition: The most direct cause is that the queue manager where the application is trying to put the message does not have a local definition of the target queue. For example, if QMGR_A tries to put to QUEUE_X, but QUEUE_X is only defined on QMGR_B and QMGR_C in the cluster, and QMGR_A doesn't have a local definition or a QREMOTE definition pointing to QUEUE_X on QMGR_B or QMGR_C.
• Incorrect Cluster Configuration: The queue manager might not be correctly joined to the cluster, or the queue definition itself (CLUSRCVR, CLUSSDR) might be faulty, preventing the queue manager from being aware of other instances of the queue within the cluster.
• Cluster Workload Exit Issues:
  • No Exit Defined: If the cluster relies on a custom workload exit to distribute messages, but this exit is not defined or is improperly configured.
  • Faulty Exit Logic: The workload exit might be present but contains logic errors that cause it to fail to choose an available queue instance. This could be due to incorrect filtering, unavailable instances, or unexpected conditions.
• Queue Not Advertised to Cluster: Although less common if cluster definitions are correct, the queue instance might not have been correctly advertised to the cluster for various reasons, making it invisible to the workload exit.

Impact on Applications

When an application receives MQRC_CLUSTER_PUT_INHIBITED (2268), the MQOPEN call fails. This means the application cannot proceed with putting messages to the intended queue. Depending on the application's error handling, this could lead to:

• Messages being lost or rejected.
• Application processes halting or failing.
• Disruption of business workflows that rely on message exchange.

Troubleshooting and Resolution

Resolving MQ error code 2268 involves systematically checking your IBM MQ cluster configuration and queue definitions.

Verifying Queue Definitions

1. Check Local Queue Definition:
   • On the queue manager where the MQOPEN call failed, use DISPLAY QLOCAL(your_queue_name) or DISPLAY QREMOTE(your_queue_name) to see if the queue is defined locally or as a remote definition pointing to a cluster queue.
   • If it's a clustered queue, ensure CLUSTER(your_cluster_name) is set correctly.
2. Verify Put Status: If a local instance exists, confirm it's not PUT(DISABLED). While PUT(DISABLED) would result in a different error (MQRC_PUT_INHIBITED), it's good practice to ensure the queue is ready for messages.

Inspecting Cluster Configuration

1. Queue Manager Cluster Membership:
   • Ensure the queue manager is correctly part of the intended cluster using DISPLAY CLUSQMGR(your_queue_manager_name).
   • Verify CLUSRCVR and CLUSSDR channels are running and correctly defined.
2. Queue Advertisements:
   • On all queue managers that are supposed to host an instance of the queue, use DISPLAY QCLUSTER(your_queue_name) to see if the queue is correctly advertised and visible across the cluster.
   • Check for any ALTER QL(your_queue_name) CLUSTER(your_cluster_name) commands that might not have propagated.

Analyzing Workload Exits

1. Workload Exit Configuration:
   • Check the queue manager attributes (DISPLAY QMGR CLWLEXIT) to see if a cluster workload exit is configured.
   • If an exit is configured, ensure its path and name are correct and the exit program is available.
2. Review Exit Logic: If a workload exit is in use, review its code and logs (if available) to understand why it might not be selecting a queue instance. This could involve issues like:
   • Incorrect filtering criteria.
   • Reliance on unavailable queue managers.
   • Logic errors.
3. Temporarily Disable Exit (for testing): If possible in a test environment, temporarily disable the cluster workload exit (ALTER QMGR CLWLEXIT('')) to see if messages are then routed (this might change routing behavior, so use with caution). If the error persists, it points away from the exit.

Error Code Summary

For a quick reference, here's a summary of MQ error code 2268:

Error Code	Symbolic Name	Explanation
2268	MQRC_CLUSTER_PUT_INHIBITED	An MQOPEN call failed because the queue manager could not find a local instance of the queue, and no cluster workload exit (or a faulty one) could select an alternative queue instance within the cluster.

By systematically addressing these points, you can pinpoint the exact cause of MQRC_CLUSTER_PUT_INHIBITED and restore proper message flow in your IBM MQ environment. For more information on IBM MQ clustering, refer to the IBM MQ Knowledge Center.