Configuring CICS to support persistent messages

CICS® provides support for sending persistent messages using the WebSphere® MQ transport protocol to a web service provider application that is deployed in a CICS region.

About this task

CICS uses Business Transaction Services (BTS) to ensure that persistent messages are recovered in the event of a CICS system failure. For this to work correctly, follows these steps:

Procedure

  1. Use IDCAMS to define the local request queue and repository file to MVS.
    You must specify a suitable value for STRINGS for the file definition. The default value of 1 is unlikely to be sufficient, and you are recommended to use 10 instead.
  2. Define the local request queue and repository file to CICS.
    Details of how to define the local request queue to CICS are described in Defining local queues in a service provider. You must specify a suitable value for STRINGS in the file definition. The default value of 1 is unlikely to be sufficient, and it is recommended that you use 10 instead.
  3. Define a PROCESSTYPE resource with the name DFHMQSOA, using the repository file name as the value for the FILE option.
  4. Ensure that during the processing of a persistent message, a program issues an EXEC CICS SYNCPOINT command before the first implicit syncpoint is requested; for example, using an SPI command such as EXEC CICS CREATE TDQUEUE implicitly takes a syncpoint.
    Issuing an EXEC CICS SYNCPOINT command confirms that the persistent message has been processed successfully. If a program does not explicitly request a syncpoint before trying to implicitly take a syncpoint, an ASP7 abend is issued.

Results

What to do next

For one way request messages, if the web service abends or backs out, sufficient information is retained to allow a transaction or program to retry the failing request, or to report the failure appropriately. You need to provide this recovery transaction or program. See Persistent message processing for details.