Execution class attributes

Each predefined or user-defined execution class comprises of a combination of three attributes: base priority, timeslice, and thread pool affinity (engine affinity in process mode). 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.

Table 4-1: Fixed-attribute composition of predefined execution classes

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.