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WS-ReliableMessaging troubleshooting tips


Tips for troubleshooting the WS-ReliableMessaging configuration.

To help you identify and resolve problems with WS-ReliableMessaging, we can use the TCP/IP monitor to view the messages that are flowing between the client applications and reliable messaging enabled Web services. We can also use the WAS trace and logging facilities.

To enable trace for WS-ReliableMessaging, set the appserver trace string as follows:

If we encounter a problem that you think might be related to WS-ReliableMessaging, we can check for error messages in the WAS admin console, and in the appserver SystemOut.log file. We can also enable the appserver debug trace to provide a detailed exception dump.

A list of the main known restrictions that apply when using WS-ReliableMessaging is provided in WS-ReliableMessaging known restrictions.

WAS system messages are logged from a variety of sources, including appserver components and applications. Messages logged by appserver components and associated IBM products start with a unique message identifier that indicates the component or application that issued the message. The prefix for the WS-ReliableMessaging component is CWSKA.

The Troubleshooter reference: Messages topic contains information about all WAS messages, indexed by message prefix. For each message there is an explanation of the problem, and details of any action that we can take to resolve the problem. Here is a set of tips to help you troubleshoot commonly-experienced problems:

 

If reliable messaging is running on a cluster, when you examine the runtime state of inbound or outbound sequences you see multiple entries for each sequence

This is because, although reliable messaging only binds to one messaging engine in a cluster, the runtime panel is calculating and displaying the sequence information once for every cluster member. Ignore the duplicate entries. Note that the slight differences in the statistics being displayed for each duplicate entry is due to the entries being created sequentially, while polling for messages continues.

 

You get runtime errors when you migrate persisted WS-ReliableMessaging messages from V6.1.0.9 or 6.1.0.11 of the Feature Pack for Web Services to a later version of

If we are migrating from WAS V6.1, and we are using V6.1.0.9 or 6.1.0.11 of the Feature Pack for Web Services, and the configuration includes WS-ReliableMessaging configured for the managed persistent quality of service, we need to remove all persisted messages before you migrate. Each message is persisted as part of a sequence that is currently being processed. To remove all persisted messages, use the admin console to complete the following steps:

  1. Navigate to the Inbound sequence collection runtime panel for the reliable messaging application.

  2. Select all the inbound sequences, then click the delete sequence and messages button to delete the sequences.

  3. Navigate to the Outbound sequence collection runtime panel, then repeat the previous steps for the outbound sequences.

 

When an appserver starts, a messaging engine used for reliable messaging is reported as unavailable

When you use reliable messaging with a managed quality of service, you might see the following exception message when the appserver starts: 

CWSIT0019E: No suitable messaging engine is available on bus theBus that matched the specified connection properties

In a network deployment environment, this can occur because the messaging engine is on an appserver or cluster member that has started later than the server that hosts your reliable messaging application. In this case we need do nothing but wait; reliable messaging will keep trying to connect until the messaging engine becomes available. If we suspect there is an underlying problem, for example the bindings are incorrect or the server that hosts the messaging engine is not going to start, complete the following checks:

 

A client application is unable to invoke a reliable messaging enabled Web service

If the client application is unable to invoke a reliable messaging enabled Web service, we can use the TCP-IP monitor to view the messages that are flowing between the client and the service. You should also check the following:

 

A sequence is not established, and therefore WS-ReliableMessaging cannot ensure messages are transmitted

After a sequence has been established, WS-ReliableMessaging provides retransmission of messages to a service. However if the sequence is not established then the messages are not transmitted to the service and a message similar to the following example is displayed: 

org.apache.axis2.AxisFault: The Create Sequence request has been refused by the RM Destination

The initial createSequence message has been refused. This is propagated back, and causes the client to fail. For information about CreateSequence and CreateSequenceRefused, see the WS-ReliableMessaging: supported specifications and standards.

You might also see a subsequent message to help explain why the request has been refused. For example: 

Caused by: javax.xml.ws.soap.SOAPFaultException: com.ibm.ws.sib.wsrm.exceptions.WSRMRuntimeException:  CWSJZ0202I: A messaging engine connection is unavailable for bus myBus.

There is a problem with the reliable messaging configuration. Complete the following checks:

For further checks that might help you resolve the problem, see also the following troubleshooting tips:

 

A sequence is established but cannot be used, and therefore WS-ReliableMessaging cannot ensure messages are transmitted

If we get an exception like the following exception, then the sequence is established but cannot be used: 

javax.xml.ws.WebServiceException: org.apache.axis2.AxisFault: The value of wsrm:Identifier is not a known Sequence identifier.

The most common reason is that we are working in a clustered environment but the server-side policy set specifies the unmanaged non-persistent quality of service. For example: The WS-I RSP default policy set specifies the unmanaged non-persistent quality of service. To use reliable asynchronous messaging in a clustered environment, use a managed quality of service to enable the cluster members to correlate reliable messaging state. To do this, either use the WS-I RSP ND default policy set, or modify the custom policy set so that the WS-ReliableMessaging policy specifies a managed quality of service, and an associated binding to a service integration bus and messaging engine. For information about how to do this, see Set a WS-ReliableMessaging policy set and Attach and binding a WS-ReliableMessaging policy set to a Web service application using the admin console. For further checks that might help you resolve the problem, see also the following troubleshooting tips:

 

The reliable messaging managed store is not initialized because the policy set binding is not complete or not valid

If the policy set specifies a managed quality of service, but we have not specified a binding to a messaging engine to support that quality of service, you get the following exception message: 

CWSKA0102E: The managed Web services reliable messaging storage manager could not be initialized because the policy set binding
 was incomplete or invalid.

Perhaps we have attached a managed policy set to the application, and used the default bindings (which do not support the managed qualities of service). You must create a new binding for the application that specifies a service integration bus and messaging engine to support the managed qualities of service. To do this, see Attach and binding a WS-ReliableMessaging policy set to a Web service application .

 

Reliable messaging is interrupted because a server is unavailable

Clustering offers maximum protection against servers becoming unavailable. It provides highly available service endpoints, and (through the service integration bus) high availability of the reliable messaging layer.

For more information about configuring high availability for Web services and messaging engines, see Balancing workloads and Adding a messaging engine to a cluster.

 

Socket timeout errors are received when running multiple reliable messaging client applications in a cluster

When many applications use the same messaging engine, it can impact performance and in some cases lead to timeout errors.

See about configuring high availability for Web services and messaging engines, see Balancing workloads and Adding a messaging engine to a cluster.

 

A message is not recovered after a server becomes unavailable, even with the managed persistent quality of service

When the reliable messaging layer receives a request message, it sends an acknowledgement then delivers the message to the target service.

There is a marginal possibility that the server hosting the reliable messaging layer could become unavailable after the request message has been acknowledged and before it has been delivered. In this case, the message is only recovered if we are using in-order delivery as well as managed persistent quality of service.

To specify in-order delivery, select the WS-ReliableMessaging policy option to deliver messages in the order that they were sent.

There is a performance overhead in using in-order delivery, because messages are held in a queue until they can be delivered in order. However, where the highest level of reliability is paramount IBM recommends that you always specify in-order delivery in conjunction with the managed persistent quality of service.

 

When using reliable messaging with a persistent WS-I RSP profile and WS-SecureConversation, an exception message states that the security context token is not valid

When you use a persistent WS-I RSP policy set, which includes WS-SecureConversation, if the scoping security context token is expired when the server is restarted then WS-ReliableMessaging cannot resend its messages and system messages are written to the log file stating that the reliable messaging sequence was not secured using the correct security token. For example: 

CWWSS7215E: Cannot get valid security context token from the cache.

To verify the scoping security context token does not expire before WS-ReliableMessaging can recover and resend its messages, complete the following task: Set WS-SecureConversation to work with WS-ReliableMessaging.


Subtopics


WS-ReliableMessaging known restrictions

 

Related tasks


Set WS-SecureConversation to work with WS-ReliableMessaging
Learn about WS-ReliableMessaging
Attach and binding a WS-ReliableMessaging policy set to a Web service application
Attach and binding a WS-ReliableMessaging policy set to a Web service application using wsadmin
Detecting and fixing problems with WS-ReliableMessaging