APT_EXECUTION_MODE environment variable in DataStage

By default, the execution mode is parallel, with multiple processes. Set APT_EXECUTION_MODE to one of the following values to run an application in sequential execution mode:

• ONE_PROCESS one-process mode
• MANY_PROCESS many-process mode
• NO_SERIALIZE many-process mode, without serialization

In ONE_PROCESS mode:

• The application runs in a single UNIX process. You need run only a single debugger session and can set breakpoints anywhere in your code.
• Data is partitioned according to the number of nodes defined in the configuration file.
• Each operator is run as a subroutine and is called the number of times appropriate for the number of partitions on which it must operate.

In MANY_PROCESS mode, the framework forks a new process for each instance of each operator and waits for it to complete rather than calling operators as subroutines.

In both cases, the step is run entirely on the Conductor node rather than spread across the configuration.

NO_SERIALIZE mode is similar to MANY_PROCESS mode, but the DataStage® persistence mechanism is not used to load and save objects. Turning off persistence might be useful for tracking errors in derived C++ classes.