Appian: Activity Chaining

Use activity-chaining to display multiple forms in succession. It allows multiple sequential process model activities run in the same user session, enabling the user move from one interface to another without page load.

Important points:

1. Activities in a process model instances are prioritized and processed based on first-in-first out approach that includes all other process activity occuring on the platform.
2. When using activity chaining, processing of that activity is given a higher prioirty in the processing queue.
3. Activity-chaining required when you want to run two attended nodes together in a process model.
4. Should not have more than 50 unattended nodes or 5seconds between to attended nodes to avoid peformance impacts.
5. Heavy/unneccesary usage of Activity chaining may experience a decrease in peformance.

Appian Recommendations:

1. Only chain when required.
2. Shorten long process chains.
3. If you chain through an asynchronous Start Process node, no connection is maintained with the process started by the smart services. Any activity chaining is seperate from the original process
4. If you chain through an synchronous Start Process node, the original process waits for other process to complete before continuing.
5. In synchronous Start Process, If chained flows encounters an attended activity, the activity will be assigned to the user that the start process smart service was run as, but it will not open the associated form.
6. known issue: If you asynchronously start a child process that uses activity chaining, the parent process may wait for the chain to end before continuing.

In Appian, **activity chaining** is a design pattern used to display multiple forms in succession to the same user, creating a “wizard-like” experience without requiring the user to return to their task list.

Activity chaining should primarily be used for API requires or user interfaces.

1. For APIs, this is often necessary because certain nodes must complete before returning values to the API caller.
2. For Interface, chaining is typically used for database writes to ensure that, upon refreshing the screen, the updated values are displayed correctly.
3. For Process models, often used to display multiple forms in succession to the same user.

Performance Recommendation: Long chains (greater than 50 node instances or requiring more than 5 seconds of processing time between tasks) are strongly discouraged as they can cause long wait times for users.

1. When you use activity chaining, all the chained activities run on the same engine(process execution) and get higher priority. If you chain too many activities together, it can take processing resources away from other activities happening on the platform for longer period of time. As a result, users or systems may experience a decrease in performance.
2. Timer event breaks activity chaining.
3. Activity-chaining into a subprocess activity
4. Overriding task assignments when activity-chaining.

Usecase1:

1. User Input task1: Upload documents.
2. User Input task2: Display the uploaded documents.

User case2: For Interface, chaining is typically used for database writes to ensure that, upon refreshing the screen, the updated values are displayed correctly.

1. Click on Record List action → “New Employee Record”
2. Enter the details and then click on Submit button
3. Newly added record should be displayed in the grid automatically

Outcome: With Active chaining & “RefereshAfter: RECORD_ACTION” option in the ReadOnly grid, we can display the newly added record in the grid automatically

“RECORD_ACTION” → Refreshes grid data each time a specified action completes.

Timer event on Activity chaining