Automatic Workload Repository

The Automatic Workload Repository (AWR) collects, processes, and maintains performance statistics for the database. The gathered data can be displayed in both reports and views. If you use services with your database, then AWR tracks metrics at the service level.

Metrics can be measured against a variety of units, including time, transactions, or database calls. For example, the number of database calls per second is a metric. Server generated alerts can be placed on these metrics when they exceed or fail to meet user-specified thresholds. The database or system administrator can then respond, for example, by:

• Using the Oracle Database Resource Manager to configure the service level for one service to have priorities relative to other services

• Stopping overloaded processes

• Modifying a service level requirement

• Implementing recovery scenarios in response to service quality changes

Using AWR metrics and performance alerts enables you to maintain continued service availability despite service level changes. It also enables you to measure the quality of service provided by the database services.

The AWR ensures that the Oracle Clusterware workload management framework and the database resource manager have persistent and global representations of performance data. This information helps Oracle Database schedule job classes by service and to assign priorities to consumer groups. If necessary, you can rebalance workloads manually with either Oracle Enterprise Manager or SRVCTL. You can also disconnect a series of sessions, but leave the service running.