WorkLoad

In the next section, automated task scheduling of tuning efforts will be explored.

Automated Task Scheduling

Oracle Database 10g scheduler helps the DBA to schedule routine administration tasks such as gathering optimizer statistics. The availability of valid statistics on the database objects helps the cost-based optimizer (CBO) generate optimal execution plans. This feature reduces the occurrence of poorly performing SQL statements due to stale or invalid statistics and enhances SQL execution performance.

The dbms_scheduler package enables the DBA to control when and where various tasks take place. By automating the routine tasks, human error can be minimized resulting in reduced operating costs.

Unfortunately, Oracle does not provide a defined process to migrate a dbms_jobs job to dbms_scheduler; the DBA must perform this manually. The scheduler does not guarantee that a job will execute on an exact time because the system may be overloaded and resources unavailable.

A program is a collection of metadata about what will be run by the scheduler. The programs can be PL/SQL block, PL/SQL procedure, Java code and C programs. A schedule specifies when and how many times a job is executed. A job specifies what needs to be executed, when to be executed, and with what parameters.