Provide native support to calculate and report historical Business Turnaround Time (Business TAT) for completed BPMN tasks using configured Work Schedules and Holiday Schedules

The customer requires the ability to calculate the Business Turnaround Time (Business TAT) for both historical and future BPMN tasks.

Business TAT represents the elapsed working time between task lifecycle events (for example, task creation/claim and completion) while excluding:

• Non-working hours
• Weekends
• Holidays defined in the configured Work Schedule and Holiday Schedule

Currently, IBM BAW records only lifecycle timestamps (creation, assignment, completion, etc.) and uses Work Schedules and Holiday Schedules during runtime for timer and deadline processing. However, the product does not calculate or persist the actual business elapsed duration for completed tasks.

As a result:

• There is no database column containing Business TAT.
• There is no REST API or Java API that returns Business TAT for completed tasks.
• There is no supported mechanism to retrospectively calculate Business TAT for historical completed tasks.
• Existing scripting approaches (for example using tw.system.calculateBusinessDate()) only support implementing custom calculations for new process instances and cannot be applied to already completed tasks.
• Performance Data Warehouse (PDWDB) only captures data after it has been enabled and therefore cannot be used to calculate Business TAT for historical tasks completed before PDWDB configuration.

The customer has approximately 500,000 completed BPMN tasks that require retrospective Business TAT calculation. Their reporting architecture already extracts BPMDB data into a dedicated Data Warehouse, so reporting does not execute directly against the Process Server database.

The requested enhancement is to provide a supported IBM capability to calculate and expose Business TAT for historical and future completed tasks using the configured Work Schedules and Holiday Schedules. Possible implementations could include one or more of the following:

• Native Business TAT calculation stored when a task completes.
• A supported API or administrative utility capable of retrospectively calculating Business TAT for historical completed tasks.
• Bulk backfill capability for existing task history.
• Business TAT exposure through supported reporting interfaces (for example PDWDB or reporting APIs).
• Ability to process large historical datasets efficiently without requiring custom implementations.

This enhancement would enable customers to perform SLA reporting and operational analytics based on actual business working time rather than calendar elapsed time, while eliminating the need to implement and maintain custom business-calendar calculations outside IBM BAW.