Using transient data queues
When a number of tasks direct large amounts of data to a single terminal (for example, a printer receiving multipage reports initiated by the users), it may be necessary to queue the data (on disk) until the terminal is ready to receive it.
About this task
Such queuing can be done on a transient data queue associated with a terminal. A special transaction, triggered when the terminal is available, can then format and present the data.
- The transient data queue should be specified as logically recoverable.
- If the transaction that presents the data fails, dynamic transaction backout will be called.
If the terminal at which the transaction runs is a printer, however, dynamic transaction backout (and a restart of the transaction by whatever means) may cause a partial duplication of output—a situation that might require special user procedures. The best solution is to ensure that each unit of work corresponds to a printer page or form.