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Oracle Event 10434 And DRM

Quote From Metalink:
In combination with event 10429/10, tracing with event 10434 at level 6 is useful for debugging internal message batching issues. Only set this event when instructed by Support or Development.


*** 2004-02-19 15:13:16.315
kjccfmb: free buff 8cc037bc, queue 8c52f064, pool 200097fc, size 408, qlen 0
*** 2004-02-19 15:13:16.316
kjccfmb: free buff 8cc037bc, queue 8c52f064, pool 200097fc, size 408, qlen 0
*** 2004-02-19 15:13:16.317
kjccfmb: free buff 8cc037bc, queue 8c52f064, pool 200097fc, size 408, qlen 0
kjccbatchstart: bflags 0x10 flag 0x0
kjccgmb_pb[new bat]: bmsg 8cf7227c mb 8cf72238 msg 8cf72298 mlen 332 dest x104 flushsz 65535
kjccbatchflush: flag 0x11 end 1 inc 2.2
kjccbatchflush[flush]: bmsg 8cf7227c blen 360 dest[1.4]
*** 2004-02-19 15:13:16.318
kjccfmb: free buff 8cf72238, queue 8c52f064, pool 200098f4, size 4128, qlen 0

Oracle10g Database 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 resource allocation.

The DRM helps to allocate a percentage of CPU time to different users, user groups, and applications. It can limit the parallelism of any 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.
Oracle10g Components of DRM

There are three main components with which you can define and manage resource allocation. They are:

* 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 groups.

The Oracle package dbms_resource_manager is used to create and maintain the resource plans and manage the resource consumer groups.

Oracle DRM - Dynamic Resource management
When using Real application Clusters (RAC), Each instance has its own SGA and buffer cache. RAC will ensure that these block changes are co-ordinated to maximize performance and to ensure data intergrity. Each copy of the buffer also called as a cache resource has a master which is one of the nodes of the cluster.

In database releases before 10g ( once a cache resource is mastered on an instance, a re-mastering or a change in the master would take place only during a reconfiguration that would happen automatically during both normal operations like instance startup or instance shutdown or abnormal events like Node eviction by Cluster Manager. So if Node B is the master of a cache resource, this resource will remain mastered on Node B until reconfiguration.

10g introduces a concept of resource remastering via DRM. With DRM a resource can be re-mastered on another node say from Node B to Node A if it is found that the cache resource is accessed more frequently from Node A. A reconfiguration is no longer the only reason for a resource to be re-mastered.


By eygle on 2009-02-20 23:46 | Comments (0) | Oracle摘 | 2201 |

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