The historic tasks that are deleted using this option are the tasks that were not selected during the progression of a workflow. E.g. If a workflow has a Pass/Fail step, and the user chooses to progress the step by selecting the Pass branch, a record will be stored in the dbo.ActivityAction table for the Fail branch as well. The same is for the tasks that require the selection of an employee to be progressed: even though a single employee is assigned to the task, records are added in the dbo.ActivityAction table for each employee from the list of employees that are eligible to be assigned to that step. In time, the size of the database can grow considerably causing performance issues, so the purpose of the Delete historic tasks option is to delete from the dbo.ActivityAction table unnecessary records.
To delete the historic tasks, open the Workflow Management Console screen then click on the Delete historic tasks option from the Actions section within the ribbon:
If there are items that can be deleted, the following dialog is displayed indicating the number of items that can be removed from the dbo.Activity Action table and the user that last ran the deletion routine and the date when the deletion routine was last performed.
Note: The historic multi action tasks and tasks that require employee selection can be deleted only for completed, cancelled or terminated workflows.
If there are no items that can be removed from the dbo.ActivityAction table, then the following dialog is displayed:
Where a large number of items are returned as available for deletion, it is recommended to perform this routine out of hours.
It is also recommended after running the deletion for a large number of items, that the Database maintenance routines are run.