Working with the Parallel Fork Node

Overview of the Parallel Fork Node

You can add a Parallel Fork node to a Flow tab in an orchestration job to run multiple nodes in the orchestration job in parallel partitions. A fork node is considered running when any or all of its child nodes are running. It is considered complete when none of the child nodes are running. In an orchestration job that includes a Parallel Fork node, the Parallel Fork node is an implicit top level fork. Any node that is a child of the top level fork is started when the job starts running.

Inputs and Outputs to the Parallel Fork Node

The Parallel Fork node can take the inputs and outputs listed in the following table:

Inputs and Outputs to the Parallel Fork Node
Name	Description
Inputs:	No unique inputs
Outputs:
CONTEXT_COUNT	The count of execution contexts that are created

Using the Parallel Fork Node

You can create an orchestration job that uses a Parallel Fork node in the Flow tab to run multiple nodes in a parallel partition. For example, you can create a job in which two Echo nodes create string outputs that are processed in additional Echo nodes that run in a Parallel Fork node. Then, the string outputs from the Echo nodes in the Parallel Fork node are written back in the Expression node in the top-level job.

The top level of this job is shown in the following display:

Parallel Fork Job

The contents of the Parallel Fork node are shown in the following display:

We can begin by examining the input values in the Echo 1 node, as shown in the following display:

Outer Echo Node Inputs

Then, we can examine the output values in the Echo 1 node, which are shown in the following display;

Outer Echo Node Outputs

Note that Echo1_String from the input is picked up in the output. You can see the same results for the Echo 2 node, except that the shared value is Echo1_String.

Now we can open the Parallel Fork node and examine the values there.

The following display shows the input values for the Echo 3 node:

Inner Echo Node Inputs

Note source binding to the string from the Echo 1 node. The Echo 2 and Echo 4 nodes work together in the same way.

The following display shows the output values for the Echo 3 node:

Inner Echo Node Outputs

Note the Echo3_Inside_Fork output.

The following display shows the Expression tab in the Expression node at the top level of the job.

Expression Tab

The output from the Echo nodes is picked up in this expression, which generates a text file with the following content: Fork_String1 = 100; Fork_String2 = 100.