Expert Oracle Exadata - Parent Directory

CHAPTER 7 RESOURCE MANAGEMENTTable 7-1. Resource Manager ComponentsNameResource consumer groupConsumer groupResource plan directivePlan directiveDirectiveResource planPlanDescriptionThese are the various names by which you may see resourceconsumer groups referred. Resource Manager allocatesresources to consumer groups, rather than user sessions. Aconsumer group is a set of database sessions that may begrouped together based on their priority, and/or resourcerequirements.These are the names by which you may see resource plandirectives referred. Resource allocations are not assigneddirectly to consumer groups. They are defined in a resourceplan directive. A consumer group is then assigned to the plandirective so that resource allocations may be enforced.Resource plans are sometimes referred to simply as “plans”, or“the plan.” Plan directives are grouped together to create aresource plan, thus defining the overarching allocation ofresources to all sessions within the database.As shown in the table, DBRM consists of three main components: resource consumer groups(consumer groups), resource plan directives (plan directives), and resource plans.Consumer groups: A consumer group can represent a single database session or agroup of sessions. Generally speaking, consumer groups consist of end users orapplication groups that share a common business priority. Grouping sessionstogether in this manner allow resources to be assigned and managed collectively.For example, in a mixed-workload database environment, consumer groupassignments allow you to collectively assign more CPU and I/O resources to yourhigh-priority business applications while reducing the resources allocated to lowpriorityapplications.Plan directives: Plan directives are where you define your resource allocations. Aplan directive is created using the CREATE_PLAN_DIRECTIVE procedure. In addition todefining the resource allocation itself (percentage of CPU, for example), theprocedure also requires you to name one resource plan and one consumer group.In this way, a plan directive “links,” or assigns a consumer group to a resource plan.Only one consumer group may be assigned to a directive, and resource planstypically consist of multiple directives. You can say that a consumer group isassigned to a resource plan through the creation of a plan directive.Resource plan: The resource plan is the collection of directives that determine howand where resources are allocated. Only one plan may be activated in the databaseinstance at any given time. The resource plan is activated by assigning it to theRESOURCE_MANAGER_PLAN instance parameter. For example, the following altersystem command activates the resource plan ‘myplan’:177