Each predefined or user-defined execution class is composed of a combination of three attributes: base priority, time slice, and engine affinity. These attributes determine performance characteristics during execution.
The attributes for the predefined execution classes, EC1, EC2, and EC3, are fixed, as shown in Table 4-1. For user-defined classes, use sp_addexeclass to create them and specify the mix of attribute values.
Execution class level |
Base priority attribute* |
Time slice attribute ** |
Engine affinity attribute*** |
|---|---|---|---|
EC1 |
High |
Time slice > t |
None |
EC2 |
Medium |
Time slice = t |
None |
EC3 |
Low |
Time slice < t |
Engine with the highest engine ID number |
By default, a task on Adaptive Server operates with the same attributes as EC2: its base priority is medium, its time slice is set to one tick, and it can run on any engine.
