Release 1 (9.0.1) for Windows
Part Number A90164-01
 Home |
 Book List |
 Contents |
 Index |  Master Index |  Feedback |
| Oracle9i Database Administrator's Guide Release 1 (9.0.1) for Windows Part Number A90164-01 |
|
Oracle9i uses initialization parameters on Windows NT to enable various features of the database every time an instance is started.
This chapter contains these topics:
An initialization parameter file is an ASCII text file containing parameters. By changing the parameters and values in an initialization file, you can specify, for example:
Every database instance has a corresponding initialization parameter file and ORACLE_SID registry parameter that points to the system identifier (SID) for the instance.
The initialization parameter filename takes the form init.ora. A single instance might have several initialization parameter files, each having some differences that affect system performance.
|
See Also:
|
By default, Oracle9i uses the initialization parameter files located in ORACLE_HOME\admin\db_name\pfile\init.ora, unless you specify a different initialization file with the PFILE option at database startup.
To customize Oracle9i database functions, you may need to edit the initialization parameter file. Only use an ASCII text editor to modify the file.
A sample file called initsmpl.ora is located in the ORACLE_BASE\ORACLE_HOME\admin\sample\pfile directory.
If you want to use the sample initsmpl.ora file as part of database creation:
init.ora.
If you installed a starter database, the initialization parameter file init.ora used by the starter database is located in ORACLE_BASE\ORACLE_HOME\admin\sample\pfile. You can use either initsmpl.ora or the starter database init.ora as a basis for creating a new Oracle9i database initialization parameter file.
The annotated, sample initialization parameter file contains alternative values for the initialization parameters. These values and the annotations are preceded by comment signs (#), which prevent them from being processed. To activate a particular parameter, remove the preceding # sign. When you no longer want to use a particular parameter, edit the initialization parameter file to add a comment sign.
For example, several initialization parameters are specified with three different values to create small, medium, or large System Global Areas (SGAs), respectively. The parameter that creates a small SGA is active in the following example:
db_block_buffers = 200 # SMALL
# db_block_buffers = 550 # MEDIUM
# db_block_buffers = 3200 # LARGE
To create a medium-sized SGA, comment out the small parameter definition and activate the medium parameter definition. Edit the initialization parameter file as follows:
# db_block_buffers = 200 # SMALL
db_block_buffers = 550 # MEDIUM
# db_block_buffers = 3200 # LARGE
The SGA_MAX_SIZE parameter holds the maximum size that the System Global Area (SGA) component can reach for a particular instance. With this release, Oracle9i can change its SGA configuration while the instance is running. This allows the sizes of the buffer cache, the shared pool, and the large pool to be changed without shutting down the instance.
Oracle9i can start instances underconfigured and allow the instance to use more memory by growing the SGA components, up to a maximum of SGA_MAX_SIZE. If no SGA_MAX_SIZE value is specified, then Oracle selects a default value that is the sum of all components specified or defaulted at initialization time. If SGA_MAX_SIZE specified in init.ora is less than the sum of all components specified or defaulted to at initialization time, then the setting of SGA_MAX_SIZE in init.ora is ignored.
|
See Also:
|
The memory allocated for an instance's SGA is displayed on instance startup when using Oracle Enterprise Manager (or SQL*Plus). You can also display the current instance's SGA size by using the SQL*Plus SHOW statement with the SGA clause.
Oracle9i Database Reference describes the default values for many initialization parameters as being operating system-specific. However, not all the parameters that Oracle9i Database Reference describes as having operating system-specific values affect Windows NT. In these cases, Windows NT uses either the default value set in the Oracle9i kernel or does not use the parameter. Table 7-1 describes these initialization parameters:
Windows NT-specific parameter values can be viewed by using an ASCII editor to open the ORACLE_BASE\ORACLE_HOME\admin\db_name\pfile\init.ora file. To display all parameter values (whether set in the init.ora file or the Oracle9i kernel), enter the following command at the SQL*Plus command prompt:
SQL> SHOW PARAMETERparameter_name
where parameter_name is the name of a specific initialization parameter.
The value for this parameter, whether defined in the ORACLE_BASE\ORACLE_HOME\admin\db_name\pfile\init.ora file or the Oracle9i kernel, displays on-screen.
Check the following initialization parameters in Table 7-2 when creating a new database. They cannot be modified after you have created the database. See Chapter 1, "Postinstallation Database Creation" for details on creating a new database, including the part of the procedure when you modify these parameters.
| Parameter | Description |
|---|---|
CHARACTER SETFoot 1 |
Specifies the database Globalization Support character set to use. This parameter can be set only when you create the database. |
|
|
Specifies the size in bytes of standard Oracle database blocks. |
|
|
Specifies the name of the database to be created. The database name is a string of eight characters or less. You cannot change the name of a database. |
1
Not an initialization parameter, but rather a clause in the CREATE DATABASE statement. See Chapter 1, "Postinstallation Database Creation" for an example of using this clause. |
Use the size guidelines in Table 7-3 to calculate Oracle9i database limits.
|
 Copyright © 1996-2001, Oracle Corporation. All Rights Reserved. |
|