16.4 IBM i Job Queue Emulation
A facility exists within Visual LANSA to allow Windows applications to emulate the type of processing, that can be provided by IBM i job queues and subsystems.
A reasonable understanding of IBM i job queues and subsystems is assumed knowledge throughout this section.
The LANSA RDML SUBMIT command is used to initiate a "batch" job from an executing RDML function. This means that the executing function starts (or spawns) another function to execute within the environment. The spawned function executes concurrently with, and completely independently of, the function that submitted it.
A shipped Visual LANSA system does not normally have IBM i job queue emulation enabled.
In this default environment the SUBMIT command works, but there is no inherent ability to queue the submitted jobs for deferred or serial execution.
If you do this:
begin_loop from(1) to(5)
submit process(demo) function(test)
end_loop
then all five spawned functions will begin to execute as soon as they are submitted. This means that it is likely that all five spawned functions will end up executing immediately (and concurrently).
However, by using the IBM i job queue emulation facility you can queue up all five functions so that they are executed serially, or so that their execution is deferred until some predetermined time (e.g. overnight).
This type of job queuing is often called "batch processing".
Also see
16.4.1 Establishing the X_JOBQ.DAT File
16.4.2 Starting, Stopping, Holding and Releasing Job Queues
16.4.4 Additional Job Queue Monitor Parameters
16.4.5 Submitting Jobs Across a Network