The Database Resource Manager provides the ability to prioritize work within the Oracle system. High priority users get resources, so as to minimize response time for online workers, for example, while lower priority users, such as batch jobs or reports, could take longer. This allows for more granular control over resources and provides features such as automatic consumer group switching, maximum active sessions control, query execution time estimation and undo pool quotas for consumer groups. Administrators can specify the maximum number of concurrently active sessions for each consumer group. Once this limit is reached, the Database Resource Manager queues all subsequent requests and runs them only after existing active sessions complete.
The Database Resource Manager solves many resource allocation problems that an operating system does not manage well.
Resources are allocated to users according to a resource plan specified by the database administrator. The following terms are used in specifying a resource plan:
A resource plan specifies how the resources are to be distributed among various users (resource consumer groups).
Resource consumer groups allow the administrator to group user sessions together by resource requirements. Resource consumer groups are different from user roles; one database user can have different sessions assigned to different resource consumer groups.
Resource allocation methods determine what policy to use when allocating for any particular resource. Resource allocation methods are used by resource plans and resource consumer groups.
Resource plan directives are a means of assigning consumer groups to particular plans and partitioning resources among consumer groups by specifying parameters for each resource allocation method.
The Database Resource Manager also allows for creation of plans within plans, called subplans. Subplans allow further subdivision of resources among different users of an application.
Levels provide a mechanism to specify distribution of unused resources among available users. Up to eight levels of resource allocation can be specified.
About Resource Consumer Groups
Creating, Editing, or Deleting Resource Plans
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