Usage notes

  1. Use the MQBEGIN call to start a unit of work that is coordinated by the queue manager and that might involve changes to resources owned by other resource managers. The queue manager supports three types of unit-of-work:
  2. If the application ends with uncommitted changes in a unit of work, the disposition of those changes depends on whether the application ends normally or abnormally. See the usage notes in MQDISC - Disconnect queue manager for further details.
  3. An application can participate in only one unit of work at a time. The MQBEGIN call fails with reason code MQRC_UOW_IN_PROGRESS if there is already a unit of work in existence for the application, regardless of which type of unit of work it is.
  4. The MQBEGIN call is not valid in an MQ client environment. An attempt to use the call fails with reason code MQRC_ENVIRONMENT_ERROR.
  5. When the queue manager is acting as the unit-of-work coordinator for global units of work, the resource managers that can participate in the unit of work are defined in the queue manager's configuration file.
  6. On i5/OS, the three types of unit of work are supported as follows: