95 DBMS_SERVICE

The DBMS_SERVICE package lets you create, delete, activate and deactivate services for a single instance.

The chapter contains the following topics:

Using DBMS_SERVICE
- Overview
- Security Model
- Constants
- Exceptions
Summary of DBMS_SERVICE Subprograms

See Also:
Oracle Database Oracle Clusterware and Oracle Real Application Clusters Administration and Deployment Guide for administering services in Real Application Clusters.

Using DBMS_SERVICE

This section contains topics which relate to using the DBMS_SERVICE package.

Overview
Security Model
Constants
Exceptions

Overview

DBMS_SERVICE supports the management of services in the RDBMS for the purposes of workload measurement, management, prioritization, and XA/and distributed transaction management.

Oracle Real Application Clusters (RAC) has a functionality to manage service names across instances. This package allows the creation, deletion, starting and stopping of services in both RAC and a single instance. Additionally it provides the ability to disconnect all sessions which connect to the instance with a service name when RAC removes that service name from the instance.

Security Model

Privileges

The client using this package should have the ALTER SYSTEM execution privilege and the V$SESSION table read privilege.

Schemas

This package should be installed under SYS schema.

Roles

The EXECUTE privilege of the package is granted to the DBA role only.

Constants

The DBMS_SERVICE package uses the constants shown in following tables

Constants used in calling arguments are described in Table 95-1, "Constants used in Calling Arguments"
Constants used in connection balancing goal arguments are described inTable 95-2, "Constants used in Connection Balancing Goal Arguments"
Constants used TAF failover attribute arguments are described inTable 95-3, "Constants used in TAF Failover Attribute Arguments"

Table 95-1 Constants used in Calling Arguments

Name	Type	Value	Description
`GOAL_NONE`	`NUMBER`	`0`	Disables Load Balancing Advisory
`GOAL_SERVICE_TIME`	`NUMBER`	`1`	Load Balancing Advisory is based on elapsed time for work done in the service plus available bandwidth to the service
`GOAL_THROUGHPUT`	`NUMBER`	`2`	Load Balancing Advisory is based on the rate that work is completed in the service plus available bandwidth to the service

Table 95-2 Constants used in Connection Balancing Goal Arguments

Name	Type	Value	Description
`CLB_GOAL_SHORT`	`NUMBER`	`1`	Connection load balancing uses Load Balancing Advisory, when Load Balancing Advisory is enabled (either `goal_service_time` or `goal_throughput`). When `GOAL`=`NONE` (no load balancing advisory), connection load balancing uses an abridged advice based on CPU utilization.
`CLB_GOAL_LONG`	`NUMBER`	`2`	Balances the number of connections per instance using session count per service. This setting is recommended for applications with long connections such as forms. This setting can be used with Load Balancing Advisory when the connection pool is sized to accommodate gravitation within the pool itself (without adding or removing connections). The latter is the most efficient design.

Table 95-3 Constants used in TAF Failover Attribute Arguments

Name	Type	Value	Description
`FAILOVER_METHOD_NONE`	`VARCHAR2`	`0`	Server side TAF is not enabled for this service
`FAILOVER_METHOD_BASIC`	`VARCHAR2`	`1`	`Server side TAF method is BASIC. BASIC` is the only value currently supported. This means that a new connection is established at failure time. It is not possible to pre-establish a backup connection. (which is to say, `PRECONNECT` is not supported)
`FAILOVER_TYPE_NONE`	`NUMBER`		Server side TAF type is `NONE`
`FAILOVER_TYPE_SESSION`	`NUMBER`		Server side TAF failover type is `SESSION`. At failure time, if the failover type is `SESSION`, TAF will re-connect to a surviving node and re-establish a vanilla database session. Customizations (for example, `ALTER` `SESSION`) must be re-executed in a failover callback.
`FAILOVER_TYPE_SELECT`	`NUMBER`		Server side TAF failover type is `SELECT`
`FAILOVER_RETRIES`	`NUMBER`		Number of retries to use during a failover. Specifies the number of times that TAF should attempt the re-connect and re-authenticate pair. The value must be integral and greater than 0. The maximum value is `UB4MAXVAL`
`FAILOVER_DELAY`	`NUMBER`		Number of seconds delay before trying to failover. Specifies the delay (in seconds) that TAF will incur if the re-connect / re-authentication fails. The value must be integral and greater than 0. The maximum value is `UB4MAXVAL`.

Usage Notes

If a TAF callback has been registered, then the failover retries and failover delay are ignored. If an error occurs, TAF will continue to re-attempt the connect and authentication as long as the callback returns a value of OCI_FO_RETRY. Any delay should be coded into the callback logic
Server side TAF settings override client-side counterparts that might be configured in TNS connect descriptors. If TAF is not configured on the client side, then at a minimum, the failover type must be set to enable TAF. If the failover type is set on the server side, then the failover method will default to BASIC. Delay and retries are optional and may be specified independently.

Exceptions

The following table lists the exceptions raised by DBMS_SERVICE package.

Table 95-4 DBMS_SERVICE Exceptions

Exception	Error Code	Description
`NULL_SERVICE_NAME`	44301	The service name argument was found to be `NULL`
`NULL_NETWORK_NAME`	44302	The network name argument was found to be `NULL`
`SERVICE_EXISTS`	44303	This service name was already in existence
`SERVICE_DOES_NOT_EXIST`	44304	The specified service was not in existence
`SERVICE_IN_USE`	44305	The specified service was running
`SERVICE_NAME_TOO_LONG`	44306	The service name was too long
`NETWORK_PREFIX_TOO_LONG`	44307	The network name, excluding the domain, was too long
`NOT_INITIALIZED`	44308	The services layer was not yet initialized
`GENERAL_FAILURE`	44309	There was an unknown failure
`MAX_SERVICES_EXCEEDED`	44310	The maximum number of services has been reached
`SERVICE_NOT_RUNNING`	44311	The specified service was not running
`DATABASE_CLOSED`	44312	The database was closed
`INVALID_INSTANCE`	44313	The instance name argument was not valid
`NETWORK_EXISTS`	44314	The network name was already in existence
`NULL_ATTRIBUTES`	44315	All attributes specified were `NULL`
`INVALID_ARGUMENT`	44316	Invalid argument supplied
`DATABASE_READONLY`	44317	The database is open read-only
`MAX_SN_LENGTH`	44318	The total length of all running service network names exceeded the maximum allowable length

Summary of DBMS_SERVICE Subprograms

Table 95-5 DBMS_SERVICE Package Subprograms

Subprogram	Description
CREATE_SERVICE Procedure	Creates service
DELETE_SERVICE Procedure	Deletes service
DISCONNECT_SESSION Procedure	Disconnects service
MODIFY_SERVICE Procedure	Modifies service
START_SERVICE Procedure	Activates service
STOP_SERVICE Procedure	Stops service

CREATE_SERVICE Procedure

This procedure creates a service name in the data dictionary. Services are also created in the data dictionary implicitly when you set the service in the service_name parameter or by means of the ALTER SYSTEM SET SERVICE_NAMES command.

Syntax

DBMS_SERVICE.CREATE_SERVICE(
   service_name        IN VARCHAR2, 
   network_name        IN VARCHAR2,
   goal                IN NUMBER DEFAULT NULL,
   dtp                 IN BOOLEAN DEFAULT NULL,
   aq_ha_notifications IN BOOLEAN DEFAULT NULL,
   failover_method     IN VARCHAR2 DEFAULT NULL,
   failover_type       IN VARCHAR2 DEFAULT NULL,
   failover_retries    IN NUMBER DEFAULT NULL,
   failover_delay      IN NUMBER DEFAULT NULL,
   clb_goal            IN NUMBER DEFAULT NULL);

Parameters

Table 95-6 CREATE_SERVICE Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary
`network_name`	The network name of the service as used in SQLNet connect descriptors for client connections. This is limited to the NET `service_names` character set (see Oracle Database Net Services Reference).
`goal`	The workload management goal directive for the service. Valid values: `DBMS_SERVICE`.`GOAL_SERVICE_TIME` `DBMS_SERVICE`.`GOAL_THROUGHPUT` `DBMS_SERVICE`.`GOAL_NONE`
`dtp`	Declares the service to be for DTP or distributed transactions including XA transactions
`aq_ha_notifications`	Determines whether HA events are sent via AQ for this service
`failover_method`	The TAF failover method for the service
`failover_type`	The TAF failover type for the service
`failover_retries`	The TAF failover retries for the service
`failover_delay`	The TAF failover delay for the service
`clb_goal`	Method used for Connection Load Balancing (see Table 95-2, "Constants used in Connection Balancing Goal Arguments")

Examples

DBMS_SERVICE.CREATE_SERVICE('ernie.us.oracle.com','ernie.us.oracle.com');

DELETE_SERVICE Procedure

This procedure deletes a service from the data dictionary.

Syntax

DBMS_SERVICE.DELETE_SERVICE(
   service_name   IN VARCHAR2);

Parameters

Table 95-7 DELETE_SERVICE Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary

Examples

DBMS_SERVICE.DELETE_SERVICE('ernie.us.oracle.com');

DISCONNECT_SESSION Procedure

This procedure disconnects sessions with the named service at the current instance.

Syntax

DBMS_SERVICE.DISCONNECT_SESSION(
   service_name   IN VARCHAR2);

Parameters

Table 95-8 DISCONNECT_SESSION Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary

Usage Notes

This procedure can be used in the context of a single instance as well as with Real Application Clusters.
This subprogram does not return until all corresponding sessions are disconnected. Therefore, use the DBMS_JOB package or put the SQL session in background if the caller does not want to wait for all corresponding sessions disconnected.

Examples

This disconnects sessions with service_name 'ernie.us.oracle.com'.

DBMS_SERVICE.DISCONNECT_SESSION('ernie.us.oracle.com');

MODIFY_SERVICE Procedure

This procedure modifies an existing service.

Syntax

DBMS_SERVICE.MODIFY_SERVICE(
   service_name        IN VARCHAR2, 
   goal                IN NUMBER DEFAULT NULL,
   dtp                 IN BOOLEAN DEFAULT NULL,
   aq_ha_notifications IN BOOLEAN DEFAULT NULL,
   failover_method     IN VARCHAR2 DEFAULT NULL,
   failover_type       IN VARCHAR2 DEFAULT NULL,
   failover_retries    IN NUMBER DEFAULT NULL,
   failover_delay      IN NUMBER DEFAULT NULL,
   clb_goal            IN NUMBER DEFAULT NULL);

Parameters

Table 95-9 MODIFY_SERVICE Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary
`goal`	The workload management goal directive for the service. Valid values: `DBMS_SERVICE`.`GOAL_SERVICE_TIME` `DBMS_SERVICE`.`GOAL_THROUGHPUT` `DBMS_SERVICE`.`GOAL_NONE`
`dtp`	Declares the service to be for DTP or distributed transactions including XA transactions
`aq_ha_notifications`	Determines whether HA events are sent via AQ for this service
`failover_method`	The TAF failover method for the service
`failover_type`	The TAF failover type for the service
`failover_retries`	The TAF failover retries for the service
`failover_delay`	The TAF failover delay for the service
`clb_goal`	Method used for Connection Load Balancing (see Table 95-2, "Constants used in Connection Balancing Goal Arguments")

START_SERVICE Procedure

This procedure starts a service. This procedure alters the service_name IOP to contain this service_name. In RAC, implementing this option will act on the instance specified.

Syntax

DBMS_SERVICE.START_SERVICE(
   service_name  IN VARCHAR2, 
   instance_name IN VARCHAR2);

Parameters

Table 95-10 START_SERVICE Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary
`instance_name`	The name of the instance where the service should be activated (optional). The instance on which to start the service. `NULL` results in starting of the service on the local instance. In single instance this can only be the current instance or `NULL`. Specify `DBMS_SERVICE`.`ALL_INSTANCES` to start the service on all configured instances.

Examples

DBMS_SERVICE.START_SERVICE('ernie.us.oracle.com');

STOP_SERVICE Procedure

This procedure stops a service, altering the service_name IOP to remove this service_name. In RAC this will call out to CRS to stop the service optionally on the instance specified.

Syntax

DBMS_SERVICE.STOP_SERVICE(
   service_name   IN VARCHAR2,
   instance_name  IN VARCHAR2);

Parameters

Table 95-11 STOP_SERVICE Procedure Parameters

Parameter	Description
`service_name`	The name of the service limited to 64 characters in the Data Dictionary
`instance_name`	The name of the instance where the service should be stopped (optional). The instance on which to stop the service. `NULL` results in stopping of the service locally. n single instance this can only be the current instance or `NULL`. The default in RAC and exclusive case is `NULL`. Specify `DBMS_SERVICE`.`ALL_INSTANCES` to stop the service on all configured instances.

Examples

DBMS_SERVICE.STOP_SERVICE('ernie.us.oracle.com');