DRAFT KB-XXXX "An error occurred while retrieving the report" in Task per Process Model report

Symptoms

When looking at the Task per Process Model report, the following error appears:

The application server log throws the following error:

2016-12-15 19:20:53,204 [ajp-/0.0.0.0:8009-4] ERROR com.appiancorp.process.analytics2.service.ProcessAnalyticsServiceFacade - com.appiancorp.kougar.driver.exceptions.Signal: index
2016-12-15 19:20:53,204 [ajp-/0.0.0.0:8009-4] ERROR com.appiancorp.process.analytics2.display.ProcessAnalyticsReportData - com.appiancorp.kougar.driver.exceptions.Signal: index
java.lang.RuntimeException: com.appiancorp.kougar.driver.exceptions.Signal: index

Cause

This issue can be caused by one of two things:

1. A constant has been created with the same name as a task metrics.
2. The Execution and Analytics engines are out of synchronization and need to be synchronized again.

Action

To fix this issue, first verify if a constant exist with the same name as a task metrics. To do so, follow these steps:

1. Navigate to the Rules tab
2. Using the search box, check if a constant with any of these names exist: 
   1. task_avg_completion
   2. Completion
   3. task_completion_time
   4. is_process_ontime
   5. is_process_overdue
   6. is_task_favorite
   7. is_task_ontime
   8. is_task_overdue
   9. Lag
   10. NetCompletion
   11. NetLag
   12. NetWork
   13. process_completion_time
   14. process_deadline
   15. process_ee_id
   16. pm_avg_completion
   17. pm_avg_lag
   18. pm_avg_work
   19. process_start_time
   20. task_assignee_owner
   21. task_assignment_time
   22. task_attributed_to
   23. task_avg_lag
   24. task_avg_work
   25. task_deadline
   26. task_ee_id
   27. task_status
   28. total_completion_time
   29. total_lag_time
   30. total_work_time
   31. Work

If a constant with a similar name exists, remove it from the system. 

After making sure that no constants exist with a same name as one in the list above, reset the analytics engines. Please refer to KB-1157 How to reset the analytics engines for on-premise installations of Appian for more details.

Affected Versions

This article applies to all versions of Appian.