Initialization file
The initialization file, usually referred to as the INIT.ORA file, is the primary file that contains configuration and tuning parameters. For detailed information on these parameters, see Chapter 12. An INIT.ORA file must exist for each Oracle instance. This file is used by Oracle when starting the database, and therefore must be located in a known location, or Oracle must be told where it is located through the use of a command-line parameter to Server Manager. In Unix systems, this file is found in the $ORACLE_HOME/dbs directory.
The INIT.ORA file is one of only two Oracle files (the other is the CONFIG.ORA file) that can be directly read and manipulated by a user—in this case, by the DBA. The INIT.ORA file is stored as plain text—ASCII on most systems—and is typically edited by the DBA, using a text editor. The file format is straightforward: it consists of multiple lines, each of which specifies a parameter in the following format:
parameter_name=parameter_value
- parameter_name
Is the name of the parameter to be assigned a value.
- parameter_value
Is the value to be assigned—either numeric or text.
The following rules apply to entries in the INIT.ORA table:
Parameter names are not case-sensitive. For example, the name “DB_Block_Buffers” is the same as “DB_BLOCK_BUFFERS” or “DB_block_buffers”.
There may be any number of spaces around the “=” sign.
Parameter names must be spelled exactly; misspellings will result in errors.
Text values may be provided without quotes.
Parameters must be specified one per line.
Comments begin with the # character (and are encouraged!).
Because the INIT.ORA file is a plain text file, it should not contain any special formatting, graphic, or control characters other than the newline character. Do not edit the INIT.ORA file with a word processing program, since these programs usually store extra control characters that will prevent the INIT.ORA file from being read properly by Oracle. Note that any error in the INIT.ORA file will prevent the database from being started.