Understanding Restart in AE

Understanding Restart in AE

Application Engine programs save to the database (perform a commit) only when an entire program successfully completes. You must set individual commits where appropriate.

At the section level, you can set a commit after each step in a section. At the step level, you can require or defer commits for individual steps, or you can increase the commit frequency within a step to N iterations of a looping action, such as a Do Select of Do While, within a step.

The commit level that you select affects how restart works in a program. Each time Application Engine issues a commit with restart enabled, it records the current state of the program. The recording of the current state that Application Engine performs is referred to as a checkpoint.

Using the restart feature enables you to perform commits more often in a program. Restart reduces the overall effect on other users and processes while the background program is running because it reduces the number of rows that are locked by the program. Fewer rows allows multiple instances of the program to run concurrently (parallel processing), which may be useful for high-volume solutions.

With restart, if a failure occurs at any point in the process, the user can restart the program and expect the program to behave as follows:

    Ignore the steps that have already completed up to the last successful commit.

    Begin processing at the next step after the last successful commit.

The ability for Application Engine to remember completed steps depends on a record called AERUNCONTROL, which is keyed by process instance.

When a program runs, each time Application Engine issues a commit it also saves all of the information required for a program restart in the AERUNCONTROL record.

Reference : Peopletools 8.53