Why you should split into sub-workflows?
If a workflow process has become overly difficult to view, contains multiple approval stages or is running into issues/errors when publishing or initiating (especially time-outs), then the overall design should be split into sub-workflows that are started by a preceding workflow in the chain.
We have listed the advantages and disadvantage of splitting up a large workflow.
Advantages of splitting a workflow into separate sub processes
1. Avoiding the repetition of a long, complex process
In a complex workflow process, an error may occur for an unexpected reason and in these cases the workflow will need to be restarted from the beginning. This is standard SharePoint behavior and is how declarative workflows operate; Nintex cannot alter this behavior.
This can potentially lead to a workflow that was nearing completion but failed during its last set of actions, which in turns means the workflow must be restarted from the very beginning and any approval type actions must be repeated.
If a workflow has been split up into sub workflows, the entire process will not need to be started from the beginning. The sub-workflow that failed can simply be started manually on the item and the appropriate start data also manually entered. This not only saves time but ensures if an unexpected issue does occur it will have the smallest impact possible.
2. Ease of troubleshooting
Smaller workflows also have the advantage of being much easier to diagnose and troubleshoot. If an error occurs in a workflow with hundreds of actions, the first step may be to reproduce the error. This can be very difficult and often is a process of running the workflow manually and editing it to determine bit by bit which actions are causing the issue. Once the issue has been determined the cause can then be investigated.
A workflow with fewer actions is much easier to manage and to determine which section or action is causing an issue. Also, in terms of error replication, a workflow with fewer actions is advantageous since there are simply fewer factors at play which could stop the real problem from being discovered.
3. Eliminating time-outs
Each time a workflow is run for the first time, a temporary version is created and compiled on the SharePoint server. When running a workflow that is overly large this process can take some time and create extra load on the server. Smaller workflows with fewer actions will compile faster and increase performance.
Disadvantages
1. Understanding your process at a glance
Splitting up a workflow means you will no longer be able to see your entire process in the one place.
For information on approaches to splitting a workflow, please see this article: Approaches to Splitting a Nintex Workflow