This sets the priority class of a database server process. The Windows scheduler uses this setting to determine when the database server and its threads get CPU time relative to other processes running at the same time.

The database server will get CPU time in preference to processes with a lower priority class, and will be pre-emptied by processes with a higher priority class. The priority classes are:

Idle - the lowest priority class, which is not recommended for a database server in normal use. A process with this priority class will only get CPU time when the system is idle (screen savers typically have this priority class).

Normal - the most usual priority class, and the one suggested for the database server.

High - this priority class is normally given to a process performing time-critical tasks which must be performed immediately. It is generally only recommended where the tasks are of short duration. A process with this priority class, and a high CPU requirement, is likely to starve other processes of CPU time.

Realtime - the highest priority class, which is not recommended for a database server in normal use. A process with this priority class can pre-empt some operating system processes and produce effects like, failure to flush disk caches or a lack of mouse response.

The priority class of the database server process determines the base priority level for its request and background threads.