Oracle Database QoS Management is a workload management (WLM) system, an automated, policy-based facility that monitors and adjusts a computer system to meet business level performance objectives. It responds gracefully to changes in system configuration and demand.
Oracle Database QoS Management monitors the performance of each work request on a target system. By accurately measuring the two components of performance, resource use and wait, bottlenecks can be quickly detected and resources reallocated to relieve them thus preserving or restoring service levels. You create a Performance Class to group work requests that require the same level of performance. You create a performance objective for each Performance Class to specify the desired level of performance for that Performance Class. You can also assign a level of business criticality, or a rank, to each Performance Class to give priority to meeting the performance objectives for a more critical Performance Class over a less critical one.
When using Oracle Database QoS Management, it enables the administrator to ensure the following:
When sufficient resources are available to meet the demand, business level performance objectives are met, even if the workload changes
When sufficient resources are not available to meet demands, the more important business objectives are met at the expense of less important ones
Oracle Database QoS Management works with Oracle Real Application Clusters (Oracle RAC) and Oracle Clusterware. A single installation of Oracle Database QoS Management operates over an entire Oracle RAC cluster, which can support a variety of applications. An application connects to the hosted databases using database services. Each call made to the Oracle RAC database is a work request.
You typically create database services to group related work requests and for managing and measuring database workload. A user initiated query against the database might use a different service than a report generation application, or a database background process. Different services can represent different types of work requests. To manage the resources used by a service, some services may be offered by several Oracle RAC instances concurrently, while others may be offered by only a single instance.
In an Oracle RAC database, Oracle Database QoS Management monitors the nodes on which user-defined database services are offered. Oracle Database QoS Management also affects the placement decisions of services based on the following input:
The individual service's usage
The importance of the work requests using that service relative to other work requests, or its relative rank
The capacity and utilization of available nodes
Other policies
Moreover, Oracle Database QoS Management periodically evaluates service placement as the workload, configuration, or Performance Class rank changes, and if needed, it provides recommendations for adjusting the level of size of server pools.
For detailed information on Oracle Real Application Clusters administration, deployment, and performance, refer to the Oracle Real Application Clusters Administration and Deployment Guide.
About the Oracle Database QOS Management Dashboard
About Cluster Managed Database Services
Managing Cluster Managed Database Services
Viewing All Targets of a Cluster
Introduction to Managing Oracle Databases
Enterprise Manager Information Roadmap
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