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Oracle9i Database Reference
Release 2 (9.2)

Part Number A96536-02
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Parameter Files

A parameter file is a file that contains a list of initialization parameters and a value for each parameter. You specify initialization parameters in a parameter file that reflect your particular installation. Oracle supports the following two types of parameter files:

Server Parameter Files

A server parameter file is a binary file that acts as a repository for initialization parameters. The server parameter file can reside on the machine where the Oracle database server executes. Initialization parameters stored in a server parameter file are persistent, in that any changes made to the parameters while an instance is running can persist across instance shutdown and startup.

Initialization Parameter Files

An initialization parameter file is a text file that contains a list of initialization parameters. The file should be written in the client's default character set.

The following are sample entries in an initialization parameter file:


The name of the initialization parameter file varies depending on the operating system. For example, it can be in mixed case or lowercase, or it can have a logical name or a variation of the name init.ora. Also supplied is an initdw.ora file, which contains suggested parameter settings for data warehouses and data marts. The database administrator can choose a different filename for the initialization parameter file.

Refer to your operating system-specific Oracle documentation for the default locations and filenames for initialization parameter files on your operating system. The initialization parameter file is read by the client-side tool used to start the server (such as SQL*Plus).

Sample initialization parameter files are provided on the Oracle distribution medium for each operating system. A sample file is sufficient for initial use, but you will probably want to modify the file to tune the database for best performance. Any changes will take effect after you completely shut down and restart the instance.

Specifying Values in the Initialization Parameter File

This section describes several aspects of setting parameter values in the initialization parameter file.

Rules Governing Parameter Files

The following rules govern the specification of parameters in initialization parameter files:

Using Special Characters in Parameter Values

If a parameter value contains a special character, then the special character must be preceded by a backslash or the entire parameter value must be enclosed in quotation marks. For example, you can specify special characters using either of the following:



Table 1-1 lists the special characters you can use in initialization parameter files.

Table 1-1  Special Characters in the Initialization Parameter File
Character Name Description


Number sign



Left parenthesis

Start list of values


Right parenthesis

End list of values


Double quotation mark

Start or end of quoted string


Single quotation mark

Start or end of quoted string


Equal sign

Separator of keyword and values



Separator of elements


Minus sign

Precedes UNIX-style keywords



Escape character

If a special character must be treated literally in the initialization parameter file, then it must either be preceded by the backslash character, or the entire string containing the special character must be enclosed in quotation marks.

Using the Escape Character

As described in "Rules Governing Parameter Files", the backslash (\) can also signify a line continuation. If the backslash is followed by an alphanumeric character, then the backslash is treated as a normal character in the input. If it is not followed by an alphanumeric character, then the backslash is treated either as a backslash or as a continuation character.

Using Quotation Marks

Quotation marks can be nested in one of two ways. The first method is to double the quotation marks in the nested string. For example:


The second method is to alternate single and double quotation marks. For example: