Submit WebSphere MQ Questions to Computer Education Techniques CETi

Submit WebSphere MQ Questions to Computer Education Techniques CETi

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Q Where can I get information on MQ reason code?
A The command mqrc in the Windows or UNIX environment displays details and numeric values for WebSphere MQ reason codes and AMQXXXX message numbers.

The IBM WebSphere MQ Information Center at http://pic.dhe.ibm.com/infocenter/wmqv7/v7r5/index.jsp  contains additional information for debugging and documentation for reason codes 

Q When is logging performed?
A Logging is performed internally by a queue manager. A queue manager's log is a record of actions performed by the queue manager in the order that they are performed.

A queue manager regularly makes the log data and queue manager data consistent with each other. This process happens during a checkpoint. Checkpoints occur automatically while a queue manager is running and when a queue manager ends.


Q How was JMS improved in MQ v7?
A In WebSphere MQ V6, a broker that was external to the WebSphere MQ queue manager managed the Publish/Subscribe functionality. One broker would be created for each queue manager and it used the same name as the queue manager. This broker used WebSphere MQ facilities to manage interactions between publishing and subscribing applications.

WebSphere MQ V7.0 provides a new Publish/Subscribe engine that is integrated into the queue manager. The queue manager now internally manages all the Publish/Subscribe functionality. The queue manager receives messages from publishers and subscription requests from subscribers for a range of topics. It is responsible for queueing and routing these messages to the target subscribers.


Q Where can I get support information regarding WebSphere MQ?
A Access to all IBM support information for the WebSphere MQ product is available at:
http://www.ibm.com/software/integration/wmq/support/

Q How does WebSphere MQ implement JMS ExceptionListeners?
A The JMS specification states that when an ExceptionListener is registered with a connection, any connection broken exceptions should be reported to the ExceptionListener. When a JMS provider detects a problem with a connection, it will inform the connectionís ExceptionListener, if a problem has been registered. This allows a JMS client to be asynchronously notified of a connection problem. Some connections only consume messages, so they would have no other way to learn that their connection has failed. The exceptions delivered to an ExceptionListener are those that have no other place to be reported.

Prior to WebSphere MQ v5.3 CSD13/CSD13 and WebSphere MQ v6.0.2.0/Fix Pack 6.0.20 connection broken exceptions were only delivered to the Exception Listener in the case of Asynchronous delivery. In case of Synchronous calls, even if an ExceptionListener was registered, connection broken exceptions were not delivered to it.


Q In WebSphere MQ when does a unit of work start?
A The unit of work is local to WebSphere MQ. It is begun automatically by WebSphere MQ, and the transaction is created automatically by WebSphere MQ. The automatic creation of local units of work occurs the first time a put or get is performed by an application, provided that WebSphere MQ is told to perform that action under syncpoint.

Q Where does the data conversion take place in WebSphere MQ?
A 1 - As the message passes through the WebSphere MQ infrastructure, data conversion can be performed each time the message reaches a new queue manager over a channel.

2 - When an application receives a message, it can specify that it wants data conversion to be performed. This data conversion is performed in the local representation used by the machine on which that application is running, or the application can request a specific representation.

The latter is the recommended method.


Q What is the default Queue Manager?
A Within the queue managers hosted on one machine, a queue manager can be configured to be the default queue manager.

When an application connects to WebSphere MQ without specifying a queue manager name, and the application is hosted on the same machine as the queue manager, the application connects to the default queue manager. Some WebSphere MQ control commands also use the default queue manager if no queue manager is specified.


Q What is the difference between MQCONN and MQCONNX?
A A) The MQI provides two functions that can be used to connect to a queue manager: MQCONN and MQCONNX.

These functions differ only in that additional options can be passed to an MQCONNX call in a connection options structure (MQCNO).


Q What options are available to configure trigger events?
A There are several ways that a queue can be configured to generate trigger events.
  1 - Generating a trigger event: Every message that arrives on a queue

A trigger message is generated for every message that arrives on the queue.

In order to enable this form of triggering on a local queue, specify the following attributes:

Trigger control to on: TRIGGER

Trigger type to every: TRIGTYPE(EVERY)

  2 - Generating a Trigger event: After a queue becomes empty

After a queue becomes empty, the first message that arrives on that queue generates a trigger event. A trigger event is usually generated if any application has the queue open for input to retrieve messages. However, if a message arrives after a specified trigger interval, and no application has the queue open for input, another trigger event occurs.

In order to enable this form of triggering on a local queue, specify the following attributes:

Trigger control to on: TRIGGER
Trigger type to first: TRIGTYPE(FIRST)
Trigger interval, which is a queue manager-wide attribute on the queue manager object, to the required number of milliseconds: TRIGINT(5000)

  3 - Generating a Trigger event : Once the total number of messages a queue is above a threshold.

A message arriving on a queue, which brings the total number of messages on a queue above a certain threshold, generates a trigger event. A trigger event is not generated if any application has the queue open for input to retrieve messages.

In order to configure triggering specify the following attributes on a local queue:

Trigger control to on: TRIGGER
Trigger type to first: TRIGTYPE(DEPTH)
Trigger depth to the threshold required: TRIGDPTH(10)


Q Do your WebSphere and MQSeries courses address the differences between WebSphere MQ and WebSphere MQ Express?
A Yes, our core WebSphere WSAS and WSAD courses address the differences between WebSphere MQ and WebSphere MQ Express. A summary of the differences in terms of the limitations in WebSphere MQ Express include:
  • WebSphere MQ Express is licensed to run only on a uniprocessor machine.
  • No more than 10 server-to-server queue manager channels may be active concurrently.
  • No more than 10 server-to-client channels may be active concurrently.
  • No extended transactional clients may be connected to this server.
  • Message size may not exceed 4 MB.

Q

My shop has operational requirements which require extensive knowledge with the WebSphere MQ Object Model. What is the WebSphere MQ Object Model? How can SYS-ED help me?

A The WebSphere MQ Object Model consists of the following:
  • Classes representing familiar WebSphere MQ concepts such as queue managers, queues, and messages.
  • Methods on each class corresponding to MQI calls.
  • Properties on each class corresponding to attributes of the WebSphere MQ objects.

FYI, we invite you to contact our Director of Education and discuss your prospective WebSphere and MQSeries training needs and application development requirements prior to enrolling in the class.


Q

My plans are to attend your WebSphere: WSAD course next year. However; I have an immediate question regarding the WebSphere MQ Explorer. Can the WebSphere MQ Explorer be used for administering a z/OS queue manager?

A No it cannot. WebSphere MQ Explorer supports the following platforms:
  • AIX and UNIX.
  • Microsoft Windows.

Q

Our shop has made a substantial investment in Microsoft .NET. Does WebSphere MQ support Microsoft .NET? And how can SYS-ED WebSphere and MQSeries courses help us migrate our first generation Visual Basic and Visual C++ to VB.NET and C# on the IBM MQ WebSphere platform.

A WebSphere MQ provides .NET classes in SupportPac MA7P. This SupportPac will allow WebSphere MQ to be invoked from Microsoft .NET applications.

Users of MA7P will require both MQSeries V5.2, 5.2.1 or WebSphere MQ V5.3 and the Microsoft.NET framework SDK. SYS-ED has extensive consulting expertise and offers comprehensive curricula in both areas.


Q

Our shop utilizes CICS Transactions Server. How does WebSphere MQ interoperate with it?

A WebSphere MQ has two interfaces to the CICS Transaction Server; the adapter and the bridge. Legacy CICS applications can be expanded with WebSphere MQ without the need to rewrite them.

This topic is covered in our WebSphere MQ (MQSeries) System Administration - OS/390 course. We also have a CICS Transactions Server course.


Q

My intention is to attend SYS-EDís WebSphere Performance Design and Tuning course in 2004. However, I have two pressing questions:

  1. Which WebSphere Application Server v5.0 trace specification option activates the embedded JMS Provider's queue manager tracing?
  2. Is there a limit to the size of the message that can be passed through the MQSeries CICS/ESA bridge?
A
  1. In order to activate WebSphere Application Server queue manager tracing, the com.ibm.ws.messaging.QueueManagerTraceListener=all=enabled is specified in the Application Server's Trace Specification General Properties setting. This group is part of the JMSQueueManager group and alternatively the JMSQueueManager=all=enabled could also be used.
  2. The limits are on the CICS side, not on MQSeries. Therefore, the DPL bridge is limited to <32KB messages and 3270 bridge is limited to the size of the 3270 datastream.

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