Oracle PL/SQL for DBAs

Managing Windows

Windows are defined durations within which a specified job runs. Using windows, you can control how resources (e.g., CPU, parallel query servers, undo pool size) are allocated and governed. When a job runs, the resource allocation method specified by the window active at that time is in effect, and it controls the resource allocation for that job.

A window has three distinct components:

• A schedule, which defines the starting time of the window

• A time duration of the window, indicating how long it is open

• A resource allocation plan that is applied to a job attached to the window

The first component may be specified using either a calendar string or a named schedule, as I described earlier for jobs. The third component may be specified via a resource manager plan, as described for programs in the previous section. In the following sections, I’ll explain the second component, the time duration of windows.