Oracle's resource manager

Yet to be finished...

dbms_resource_manager is the interface to administer the Database Resource Manager. Using the Database Resource Manager, it is possible to

• Guarantee certain users a minimum amount of processing resources regardless of the load on the system and the number of users
• Distribute available processing resources by allocating percentages of CPU time to different users and applications. In a data warehouse, a higher percentage may be given to ROLAP (relational on-line analytical processing) applications than to batch jobs.
• Limit the degree of parallelism of any operation performed by members of a group of users
• Create an active session pool. This pool consists of a specified maximum number of user sessions allowed to be concurrently active within a group of users. Additional sessions beyond the maximum are queued for execution, but you can specify a timeout period, after which queued jobs will abort.
• Allow automatic switching of users from one group to another group based on administrator defined criteria. If a member of a particular group of users creates a session that executes for longer than a specified amount of time, that session can be automatically switched to another group of users with different resource requirements.
• Prevent the execution of operations that are estimated to run for a longer time than a predefined limit
• Create an undo pool. This pool consists of the amount of undo space that can be consumed in by a group of users.
• Configure an instance to use a particular method of allocating resources. You can dynamically change the method, for example, from a daytime setup to a nighttime setup, without having to shut down and restart the instance.

The resource manager is enabled by setting the resource_manager_plan initialization parameter to an existing plan.