Control Flow of Execution
SAP Data Hub provides the data workflow operators Workflow Merge (OR), Workflow Merge (AND), and Workflow Split to control the flow of execution in a data workflow.
Workflow Merge (OR)
A message is sent to the output port once the operator receives a message at any of its input ports. All further inputs are ignored.
The operator has two input ports and one output port.
Workflow Merge (AND)
This operator sends a message to the output port once it receives a message on both the input ports. The process shuts down after sending the message.
The Workflow Merge (AND) operator is intended to control the flow of execution when there are parallel executions within the data workflow.
The operator has two input ports and one output port. Leaving the output port unconnected results in a data workflow execution failure once the operator receives an input message.
This operator helps duplicate an input message into two output messages.
The Workflow Split operator is intended to control the flow of execution when there are parallel executions within the graph.
The operator has one input port and two output ports. Operator sends the message at the input port to both the output ports.
Consider this data workflow example that uses the Workflow Split, Workflow Merge (AND), and Workflow Merge (OR) operators.
In this example, after the engine successfully executes the Pipeline operator, the output message is duplicated to both the SAP HANA Flowgraph operator and the SAP BW Process Chain operator. This means that, both of the latter operators will run in parallel. The Workflow Merge (AND) operator ensures that a message is sent to the SAP Data Services operator only if both the operators have finished successfully. The Workflow Merge (OR) operator takes the first incoming message and forwards it to the Workflow Terminator operator that shuts down the data workflow execution.