The RAPCache database contains predefined and user-defined execution classes that can be used to improve the performance of activities that communicate with the RAPCache.
The RAPCache database internally assigns “tasks” for every established connection so that each activity that communicates with the RAPCache database has one or more tasks associated with it. When system resources are limited, conflicts may arise between several tasks that require the same resource.
An execution class is a specific combination of execution attributes that specify values for task priority, time slice, and task-to-engine affinity.
- The task priority attribute determines which task is granted access to a resource when several tasks compete for it. For example, a task with a higher priority is preferred over a lower priority task.
- The engine affinity attribute lets you assign a task to an engine or to a group of engines.
- The time slice attribute determines the time period that each task is allowed to execute on a particular engine before relinquishing its control to another task associated with the same engine.
The RAPCache database contains two execution class types:
- Predefined execution classes are available, and cannot be customized.
- User-defined execution classes are customizable and can be configured to use a particular engine or a particular group of engines.
To boost activity performance, create a user-defined execution class and associate the activity with it. To do this, bind the activity “application name” with the execution class. Sybase recommends that you create one or more user-defined execution classes for each activity that communicates with the RAPCache database. See
Adaptive Server Enterprise Performance and Tuning: Basics.