Service Workload Management

Oracle 10g has expanded the usage of database services by offering enhanced support for workload management. The idea behind the 10g service-management framework is to improve the manageability and increase the availability, recoverability, and performance of resources that share the same functionality and/or expectations and are grouped as one logical unit of work. Although service management can be used in both single-instance and RAC databases, 10g RAC service management can span one or more instances within a cluster. This capability provides a single system image for competing resources running within a single instance or across multiple instances in a cluster. Now with 10g RAC, services running in a failed node can be automatically routed to a surviving node without users experiencing any noticeable outage. 10g CRS takes this a step further by restarting the failed node when available and relocating the misplaced services back to their original locations.

Within the new 10g service-management framework, two types of services can be utilized: application services and internal services. Application services are used to support business logic and/or requirements that you may have with your application or data. Within application services, the workload-management capabilities are further broken down into three separate categories:

• Functional services. Resources working together for a common business function or requirement.

• Data-dependent services. Resources that utilize services based on data key values.

• Pre-connect services. Resources that span a set of clustered instances to maximize availability requirements.

In addition to application services, Oracle 10g also offers two internal services for workload management:

• SYS$BACKGROUND. Used by related background processes for workload-management support.

• SYS$USER. Default service for user sessions not assigned with any application service.

Application services can be created, stopped, and even disabled, but internal services can never be stopped or disabled.

10g Service Management Limitations

Currently in 10g Release 1, you can only have 64 services per databasetwo internal services and 62 application services.

With Oracle 10g, anyone can create a new service by using the Database Configuration Assistant (DBCA), Server Control (SRVCTL), or manually with the DBMS_SERVICE package. For backward compatibility, services can also be created and started by using the SERVICE_NAMES initialization parameter.