Initialization commands for IBM MQ for z/OS

Initialization commands can be used to control the queue manager startup.

Commands in the initialization input data sets are processed when IBM MQ is initialized on queue manager startup. Three types of command can be issued from the initialization input data sets:

• Commands to define IBM MQ entities that cannot be defined elsewhere, for example DEFINE BUFFPOOL.

  These commands must reside in the data set identified by the DD name CSQINP1. They are processed before the restart phase of initialization. They cannot be issued through the console, operations and control panels, or an application program. The responses to these commands are written to the sequential data set that you refer to in the CSQOUT1 statement of the started task procedure.

• Commands to define IBM MQ objects that are recoverable after restart. These definitions must be specified in the data set identified by the DD name CSQINP2. They are stored in page set zero. CSQINP2 is processed after the restart phase of initialization. The responses to these commands are written to the sequential data set that you refer to in the CSQOUT2 statement of the started task procedure.
• Commands to manipulate IBM MQ objects. These commands must also be specified in the data set identified by the DD name CSQINP2. For example, the IBM MQ-supplied sample contains an ALTER QMGR command to specify a dead-letter queue for the subsystem. The response to these commands is written to the CSQOUT2 output data set.

Note: If IBM MQ objects are defined in CSQINP2, IBM MQ attempts to redefine them each time the queue manager is started. If the objects already exist, the attempt to define them fails. If you need to define your objects in CSQINP2, we can avoid this problem by using the REPLACE parameter of the DEFINE commands, however, this overrides any changes that were made during the previous run of the queue manager.

Sample initialization data set members are supplied with IBM MQ for z/OS®. They are described in Sample definitions supplied with IBM MQ.

Initialization commands for distributed queuing

We can also use the CSQINP2 initialization data set for the START CHINIT command. If you need a series of other commands to define your distributed queuing environment (for example, starting listeners), IBM MQ provides a third initialization input data set, called CSQINPX, that is processed as part of the channel initiator started task procedure.

The MQSC commands contained in the data set are executed at the end of channel initiator initialization, and output is written to the data set specified by the CSQOUTX DD statement. You might use the CSQINPX initialization data set to start listeners for example.

A sample channel initiator initialization data set member is supplied with IBM MQ for z/OS. It is described in Sample definitions supplied with IBM MQ.

Initialization commands for publish/Subscribe

If you need a series of commands to define your publish/subscribe environment (for example, when defining subscriptions), IBM MQ provides a fourth initialization input data set, called CSQINPT.

The MQSC commands contained in the data set are executed at the end of publish/subscribe initialization, and output is written to the data set specified by the CSQOUTT DD statement. You might use the CSQINPT initialization data set to define subscriptions for example.

A sample publish/subscribe initialization data set member is supplied with IBM MQ for z/OS. It is described in Sample definitions supplied with IBM MQ.