“Priority Changes” reports the priority changes that took place for all user tasks in each priority run queue during the sample interval. It is normal to see some priority switching due to system-related activity. Such priority switching occurs, for example, when:
A task sleeps while waiting on a lock – Adaptive Server temporarily raises the task’s priority.
A housekeeper task sleeps – Adaptive Server raises the priority to medium when the housekeeper wash and housekeeper chores task wake up, and changes them back to low priority when they go back to sleep.
A task executes a stored procedure – the task assumes the priority of the stored procedure and resumes its previous priority level after executing the procedure.
If you are using logical process management and there are a high number of priority changes compared to steady state values, it may indicate that an application, or a user task related to that application, is changing priorities frequently. Check priority change data for individual applications. Verify that applications and logins are behaving as you expect.
If you determine that a high-priority change rate is not due to an application or to related tasks, then it is likely due to system activity.
“Total Priority Changes” reports the total number of priority changes during the sample period. This section gives you a quick way to determine if there are a high number of run queue priority changes occurring.
