At a minimum, each customized operator must define the user-provided control functions listed in the following table.
|Initiate||Preparing the operating environment for executing operators by performing the following tasks:
|Execute||Performing the following data access and manipulation tasks:
|Checkpoint||Writing checkpoint records to a restart log table that the operator can use to restart in case of a hardware or software system failure.|
|Restart||Restarting operators using the most recently written checkpoint records.|
|Event||Performing event processing or notification based on caller-specified event.|
|Terminate||Releasing system resources allocated by the corresponding Initiate function.|