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Grid Control is utility that
manages, monitors many diverse resources with in the enterprise
grid. Such resources include, Database Systems, Hosts
(blades/servers), application servers, web applications and storage
devices. It is also extensible, so that extra components that are
not supported out of the box can be added. From a single place, Grid
control allows the comparison of performance levels of various
Grid Control can do the
day-to-day management or administration on all these controlled
resources. As the performance metrics are analyzed in a certain time
frames, the inter-relations between the related resources can be
easily understood, which leads to better problem solutions. More
details on using the Grid Control Utility in the chapter in this
book on Using Grid Control Utility.
Oracle Resource Manager
Database Resource Manager (DRM)
provides the resource management facilities. In a database instance,
which is highly active and concurrently accessed by large numbers of
users, control of suitable resource allocation is essential. In the
absence of a better resource control, some critical and high
priority sessions or tasks may not get required resources in time.
Oracle DRM is a framework that provides a mechanism to control the
The DRM helps to allocate a
percentage of CPU time to different users, user groups, and
applications. It can limit the parallelism of operation by allowing
other competing processes to get their share of resources. It also
can create resource pools, such as the undo pool and the active
session pool that help control the execution resource availability
for a group of sessions.
Components of DRM
There are three main components
with which the DBA can define and manage resource allocation. They
* Resource Consumer Group: These
are the named entities, which are groups of users or sessions
combined together, based on their processing and resource needs.
* Resource Plan: Contains the
directives that specify how the resources are allocated to the
resource consumer groups.
* Resource Plan Directive: These
are used to associate resource consumer groups with particular
resource plans and allocate resources among the resource consumer
The Oracle package
dbms_resource_manager is used to create and maintain the resource
plans and manage the resource consumer groups.
Resource and Plan Directives
The resource plan can be a
single-level resource plan or it can be a multi-level resource plan.
In a single-level resource plan, the resources are allocated among
the associated resource groups. For example, the policy_rec plan
allocates CPU resources among the three consumer groups viz.,
claims, sales, and legal. The resource group claims gets 55% of CPU
time, sales gets 25%, and legal receives 20% of CPU time.
In a multi-level resource plan,
sub-plans represent a hierarchy of plans and their associated
resource groups. The policy_rec provides for two sub-plans, sales
and claims, and one resource group named legal. The claims sub-plan
allocates 60% of CPU time to the resource group called LIFE and 40%
to the group called AUTO. The sales sub-plan allocates 70% of CPU
time to the resource group called NEWSALES and 30% to the group
The resource plan directives
specify how the resources are allocated to resource consumer groups.
There are many resources involved in the database activity, which
can be controlled by DRM. The resources include CPU availability for
the competing resource groups, the number of simultaneous active
sessions allowed within a consumer group, the degree of parallelism,
the execution time limit, and the undo pool.