APT_EXECUTION_MODE

The APT_EXECUTION_MODE environment variable is available in the InfoSphere® DataStage® Administrator under the Parallel branch. By default, the execution mode is parallel, with multiple processes. Set the APT_EXECUTION_MODE variable 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 executes in a single UNIX process. You need only run 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 InfoSphere DataStage persistence mechanism is not used to load and save objects. Turning off persistence might be useful for tracking errors in derived C++ classes.