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Initialization Parameter Files

Oracle8 for Windows NT uses initialization parameters to enable various features of the database every time an instance is started.

Specific topics discussed are:

What Is an Initialization Parameter File?

An initialization parameter file is an ASCII text file containing a list of parameters. 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 file names take the form INITSID.ORA, where SID is the name of the database instance. For example, the initialization parameter file for the starter database is named INITORCL.ORA, because the initial database SID is ORCL.

A single instance might also have several initialization parameter files, each having some differences to affect system performance.

Additional Information:

See Oracle8 Server Reference for a complete list and descriptions of all initialization parameters.

By changing the parameter values in an initialization file, you can specify, for example:

the amount of memory the database uses
whether to archive filled online redo logs
which control files currently exist for the database

Location

The computer for which the database instance is started must have access to the appropriate initialization parameter files. By default, Oracle8 uses the initialization parameter files located in ORACLE_HOME\DATABASE, unless you specify a different initialization file with the PFILE option at database startup.

Editing

To customize Oracle8 database functions, you may need to edit the initialization parameter files. Use any ASCII text editor to modify the file.

Sample File

The initialization parameter file INITORCL.ORA used by the starter database that you can install with Oracle8 is located in ORACLE_HOME\DATABASE. You can use this file as a model for creating a new Oracle8 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

Initialization Parameters

Oracle8 Server Reference includes descriptions of all initialization parameters and instructions for setting and displaying their values. The following table describes initialization parameters and default values for Oracle8 for Windows NT.

Initialization Parameter Name	Default Value	Range of Values
AUDIT_TRAIL	TRUE	NONE (FALSE), DB (TRUE), OS
BACKGROUND_DUMP_ DEST	%RDBMSnn%\TRACE\	Any valid directory
COMPATIBLE	8.0.0.0.0	Default release to current release
COMMIT_POINT_ STRENGTH	1	0 - 255
CONTROL_FILES	%ORACLE_HOME%\DATABASE\ CTL1%ORACLE_SID%.ORA	Any valid path and filename
DB_BLOCK_BUFFERS	200	200 to 3200
DB_BLOCK_SIZE	2048	512 - 16384
DB_FILES	20	0 - 1022
DB_FILE_MULTIBLOCK_ READ_ COUNT¹	8	1 - 31²
DB_FILE_SIMULTANEOUS_ WRITES	4	1 - 24
DB_NAME	ORACLE	Any valid database name limited to a maximum of eight characters.
DISTRIBUTED_TRANSACTIONS	25 * TRANSACTIONS	0 - TRANSACTIONS
DML_LOCKS	4 * transactions	20 to unlimited
LOG_ARCHIVE_BUFFER_ SIZE	127	1 - 127
LOG_ARCHIVE_BUFFERS	4	1 - 8
LOG_ARCHIVE_DEST	%RDBMSnn%\	Any valid directory
LOG_ARCHIVE_FORMAT	ARC%S.%T	A valid filename format
LOG_ARCHIVE_START	None	TRUE or FALSE
LOG_CHECKPOINT_ INTERVAL	8000	2 - Unlimited
LOG_FILES	255	2 - 255
LOG_SMALL_ENTRY_MAX_ SIZE	800	0 - Unlimited
MAX_DUMP_FILE_SIZE	10240	0 to 4,000,000
MTS_MAX_DISPATCHERS	(unused)	(unused)
MTS_MAX_SERVERS	(unused)	(unused)
MTS_SERVERS	(unused)	(unused)
NLS_LANGUAGE	AMERICAN	Any valid language
NLS_SORT	(Language dependent)	(Language dependent)
NLS_TERRITORY	AMERICA	Any valid territory
OPEN_CURSORS	50	1 - Unlimited
OS_AUTHENT_PREFIX	OPS$	Any character string
PROCESSES	25	3 - Unlimited
REMOTE_LOGIN_ PASSWORDFILE	SHARED	SHARED, EXCLUSIVE, NONE
SNAPSHOT_REFRESH_PROCESSES	0	0 to 10
SEQUENCE_CACHE_ENTRIES	10	10 to 32000
SHARED_POOL_SIZE	6,500,000	300 KB - Unlimited
SORT_AREA_SIZE	65536	0 - Unlimited
SORT_READ_FAC	20	0 - Unlimited
SORT_SPACEMAP_SIZES	512	0 - Unlimited
TEXT_ENABLE	TRUE	TRUE or FALSE
TIMED_STATISTICS	None	TRUE or FALSE
TEMPORARY_TABLE_ LOCKS	SESSIONS	0 - Unlimited
TRANSACTIONS_PER_ ROLLBACK_ SEGMENT	30	1 - 255
USER_DUMP_DEST	%RDBMSnn%\TRACE	Any valid directory

¹ MAX_IO_SIZE is not an initialization parameter. However, it is used to calculate the maximum value of DB_FILE_MULTIBLOCK_READ_COUNT. On Windows NT, MAX_IO_SIZE is set to 64 KB - 512, or 65012 bytes. The maximum value of DB_FILE_MULTIBLOCK_READ_COUNT for a given block size is 65012 divided by the value of DB_BLOCK_SIZE. This result is rounded down to the next whole number. So, for DB_BLOCK_SIZE equal to 8192, the maximum value of DB_FILE_MULTIBLOCK_READ_COUNT is 65012/8192, which rounds to 7. For a DB_BLOCK_SIZE of 2048, the maximum value is 31, and so on.
² Depends on value for DB_BLOCK_SIZE parameter.

Creating a New Database-Initialization Parameters

Check the following initialization parameters when creating a new database; they cannot be modified after you have created the database. See Chapter 9, "Creating a Database" for details on creating a new database, including the part of the procedure when you modify these parameters.

Parameter	Description
DB_NAME	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.
DB_BLOCK_SIZE	Specifies the size in bytes of Oracle database blocks.
CHARACTER SET¹	Specifies the database NLS character set to use. This parameter can be set only when you create the database.

¹ Not an initialization parameter, but rather a clause in the CREATE DATABASE statement. See Chapter 9, "Creating a Database" for an example of using this clause.

B Initialization Parameter Files