5 OLAP_API_SESSION_INIT

The OLAP_API_SESSION_INIT package provides procedures for maintaining a table of initialization parameters for the OLAP API.

This chapter contains the following topics:

Initialization Parameters for the OLAP API
Viewing the Configuration Table
Summary of OLAP_API_SESSION_INIT Subprograms

Initialization Parameters for the OLAP API

The OLAP_API_SESSION_INIT package contains procedures for maintaining a configuration table of initialization parameters. When the OLAP API opens a session, it executes the ALTER SESSION commands listed in the table for any user who has the specified roles. Only the OLAP API uses this table; no other type of application executes the commands stored in it.

This functionality provides an alternative to setting these parameters in the database initialization file or the init.ora file, which would alter the environment for all users.

During installation, the table is populated with ALTER SESSION commands that have been shown to enhance the performance of the OLAP API. Unless new settings prove to be more beneficial, you do not need to make changes to the table.

The information in the table can be queried through the ALL_OLAP_ALTER_SESSION view alias, which is also described in this chapter.

Note:

This package is owned by the SYS user. To use it, you must either be a privileged user or have explicit execution rights.

Viewing the Configuration Table

ALL_OLAP_ALTER_SESSION is the public synonym for V$OLAP_ALTER_SESSION, which is a view of the OLAP$ALTER_SESSION table. The view and table are owned by the SYS user.

ALL_OLAP_ALTER_SESSION View

Each row of ALL_OLAP_ALTER_SESSION identifies a role and a session initialization parameter. When a user opens a session using the OLAP API, the session is initialized using the parameters for roles granted to that user. For example, if ALL_OLAP_ALTER_SESSION has rows for the OLAP_USER and the OLAP_DBA roles, then a user with the OLAP_USER role will only have the privileges set for the OLAP_USER role. The privileges for the OLAP_DBA role will be ignored.

Table 5-1 ALL_OLAP_ALTER_SESSION Column Descriptions

Column	Datatype	NULL	Description
`ROLE`	`VARCHAR2(30)`	`NOT NULL`	A database role
`CLAUSE_TEXT`	`VARCHAR2(3000)`		An `ALTER SESSION` command

Summary of OLAP_API_SESSION_INIT Subprograms

The following table describes the subprograms provided in OLAP_API_SESSION_INIT.

Table 5-2 OLAP_API_SESSION_INIT Subprograms

Subprogram	Description
ADD_ALTER_SESSION Procedure	Specifies an `ALTER SESSION` parameter for OLAP API users with a particular database role.
CLEAN_ALTER_SESSION Procedure	Removes orphaned data, that is, any `ALTER SESSION` parameters for roles that are no longer defined in the database.
DELETE_ALTER_SESSION Procedure	Removes a previously defined `ALTER SESSION` parameter for OLAP API users with a particular database role.

ADD_ALTER_SESSION Procedure

This procedure specifies an ALTER SESSION parameter for OLAP API users with a particular database role. It adds a row to the OLAP$ALTER_SESSION table.

Syntax

ADD_ALTER_SESSION (
     role_name           IN      VARCHAR2,
     session_parameter   IN      VARCHAR2 );

Parameters

The role_name and session_parameter are added as a row in OLAP$ALTER_SESSION.

Table 5-3 ADD_ALTER_SESSION Procedure Parameters

Parameter	Description
`role_name`	The name of a valid role in the database. Required.
`session_parameter`	A parameter that can be set with a SQL `ALTER SESSION` command. Required.

Example

The following example inserts a row in OLAP$ALTER_SESSION that turns on query rewrite for users with the OLAP_DBA role.

SQL> EXECUTE olap_api_session_init.add_alter_session('OLAP_DBA', 
     'SET QUERY_REWRITE_ENABLED=TRUE');
Row inserted
 
SQL> SELECT * FROM all_olap_alter_session WHERE role='OLAP_DBA';
 
ROLE         CLAUSE_TEXT
------------ ------------------------------------------------------------
OLAP_DBA     ALTER SESSION SET QUERY_REWRITE_ENABLED=TRUE

CLEAN_ALTER_SESSION Procedure

This procedure removes all ALTER SESSION parameters for any role that is not currently defined in the database. It removes all orphaned rows in the OLAP$ALTER_SESSION table for those roles.

Syntax

CLEAN_ALTER_SESSION ();

Example

The following example deletes all orphaned rows.

SQL> EXECUTE olap_api_session_init.clean_alter_session();

DELETE_ALTER_SESSION Procedure

This procedure removes a previously defined ALTER SESSION parameter for OLAP API users with a particular database role. It deletes a row from the OLAP$ALTER_SESSION table.

Syntax

DELETE_ALTER_SESSION (
     role_name           IN      VARCHAR2,
     session_parameter   IN      VARCHAR2);

Parameters

The role_name and session_parameter together uniquely identify a row in OLAP$ALTER_SESSION.

Table 5-4 DELETE_ALTER_SESSION Procedure Parameters

Parameter	Description
role_name	The name of a valid role in the database. Required.
session_parameter	A parameter that can be set with a SQL `ALTER SESSION` command. Required.

Examples

The following call deletes a row in OLAP$ALTER_SESSION that contains a value of OLAP_DBA in the first column and QUERY_REWRITE_ENABLED=TRUE in the second column.

SQL> EXECUTE olap_api_session_init.delete_alter_session('OLAP_DBA', 
     'SET QUERY_REWRITE_ENABLED=TRUE');
 
SQL> SELECT * FROM all_olap_alter_session WHERE role='OLAP_DBA';
 
no rows selected