17 Using Oracle Managed Files
Oracle Database can manage the files that comprise the database.
- About Oracle Managed Files
Oracle Managed Files eases database administration, reduces errors, and reduces wasted disk space. - Enabling the Creation and Use of Oracle Managed Files
You set certain initialization parameters to enable and use Oracle Managed Files. - Creating Oracle Managed Files
You can use Oracle Managed Files to create data files, temp files, control files, redo log files, and archived log. - Operation of Oracle Managed Files
The file names of Oracle Managed Files are accepted in SQL statements wherever a file name is used to identify an existing file. - Scenarios for Using Oracle Managed Files
Scenarios illustrate how to use Oracle Managed Files.
Parent topic: Oracle Database Structure and Storage
17.1 About Oracle Managed Files
Oracle Managed Files eases database administration, reduces errors, and reduces wasted disk space.
- What Is Oracle Managed Files?
Using Oracle Managed Files simplifies the administration of an Oracle Database. Oracle Managed Files eliminates the need for you, the DBA, to directly manage the operating system files that comprise an Oracle Database. - Who Can Use Oracle Managed Files?
Oracle Managed Files is most useful for certain types of databases. - What Is a Logical Volume Manager?
A logical volume manager (LVM) is a software package available with most operating systems. Sometimes it is called a logical disk manager (LDM). It allows pieces of multiple physical disks to be combined into a single contiguous address space that appears as one disk to higher layers of software. - What Is a File System?
A file system is a data structure built inside a contiguous disk address space. A file manager (FM) is a software package that manipulates file systems, but it is sometimes called the file system. - Benefits of Using Oracle Managed Files
Oracle Managed Files provides several benefits. - Oracle Managed Files and Existing Functionality
Using Oracle Managed Files does not eliminate any existing functionality.
Parent topic: Using Oracle Managed Files
17.1.1 What Is Oracle Managed Files?
Using Oracle Managed Files simplifies the administration of an Oracle Database. Oracle Managed Files eliminates the need for you, the DBA, to directly manage the operating system files that comprise an Oracle Database.
With Oracle Managed Files, you specify file system directories in which the database automatically creates, names, and manages files at the database object level. For example, you need only specify that you want to create a tablespace; you do not need to specify the name and path of the tablespace's data file with the DATAFILE
clause. This feature works well with a logical volume manager (LVM).
The database internally uses standard file system interfaces to create and delete files as needed for the following database structures:
-
Tablespaces
-
Redo log files
-
Control files
-
Archived logs
-
Block change tracking files
-
Flashback logs
-
RMAN backups
Through initialization parameters, you specify the file system directory to be used for a particular type of file. The database then ensures that a unique file, an Oracle managed file, is created and deleted when no longer needed.
This feature does not affect the creation or naming of administrative files such as trace files, audit files, alert logs, and core files.
See Also:
Oracle Automatic Storage Management Administrator's Guide for information about Oracle Automatic Storage Management (Oracle ASM), the Oracle Database integrated file system and volume manager that extends the power of Oracle Managed Files. With Oracle Managed Files, files are created and managed automatically for you, but with Oracle ASM, you get the additional benefits of features such as striping, software mirroring, and dynamic storage configuration, without the need to purchase a third-party logical volume manager.
Parent topic: About Oracle Managed Files
17.1.2 Who Can Use Oracle Managed Files?
Oracle Managed Files is most useful for certain types of databases.
Oracle Managed Files are most useful for the following types of databases:
-
Databases that are supported by the following:
-
A logical volume manager that supports striping/RAID and dynamically extensible logical volumes
-
A file system that provides large, extensible files
-
-
Low end or test databases
Because Oracle Managed Files require that you use the operating system file system, you lose control over how files are laid out on the disks, and thus, you lose some I/O tuning ability.
Parent topic: About Oracle Managed Files
17.1.3 What Is a Logical Volume Manager?
A logical volume manager (LVM) is a software package available with most operating systems. Sometimes it is called a logical disk manager (LDM). It allows pieces of multiple physical disks to be combined into a single contiguous address space that appears as one disk to higher layers of software.
An LVM can make the logical volume have better capacity, performance, reliability, and availability characteristics than any of the underlying physical disks. It uses techniques such as mirroring, striping, concatenation, and RAID 5 to implement these characteristics.
Some LVMs allow the characteristics of a logical volume to be changed after it is created, even while it is in use. The volume may be resized or mirrored, or it may be relocated to different physical disks.
Parent topic: About Oracle Managed Files
17.1.4 What Is a File System?
A file system is a data structure built inside a contiguous disk address space. A file manager (FM) is a software package that manipulates file systems, but it is sometimes called the file system.
All operating systems have file managers. The primary task of a file manager is to allocate and deallocate disk space into files within a file system.
A file system allows the disk space to be allocated to a large number of files. Each file is made to appear as a contiguous address space to applications such as Oracle Database. The files may not actually be contiguous within the disk space of the file system. Files can be created, read, written, resized, and deleted. Each file has a name associated with it that is used to refer to the file.
A file system is commonly built on top of a logical volume constructed by an LVM. Thus all the files in a particular file system have the same performance, reliability, and availability characteristics inherited from the underlying logical volume. A file system is a single pool of storage that is shared by all the files in the file system. If a file system is out of space, then none of the files in that file system can grow. Space available in one file system does not affect space in another file system. However some LVM/FM combinations allow space to be added or removed from a file system.
An operating system can support multiple file systems. Multiple file systems are constructed to give different storage characteristics to different files as well as to divide the available disk space into pools that do not affect each other.
Parent topic: About Oracle Managed Files
17.1.5 Benefits of Using Oracle Managed Files
Oracle Managed Files provides several benefits.
Consider the following benefits of using Oracle Managed Files:
-
They make the administration of the database easier.
There is no need to invent file names and define specific storage requirements. A consistent set of rules is used to name all relevant files. The file system defines the characteristics of the storage and the pool where it is allocated.
-
They reduce corruption caused by administrators specifying the wrong file.
Each Oracle managed file and file name is unique. Using the same file in two different databases is a common mistake that can cause very large down times and loss of committed transactions. Using two different names that refer to the same file is another mistake that causes major corruptions.
-
They reduce wasted disk space consumed by obsolete files.
Oracle Database automatically removes old Oracle Managed Files when they are no longer needed. Much disk space is wasted in large systems simply because no one is sure if a particular file is still required. This also simplifies the administrative task of removing files that are no longer required on disk and prevents the mistake of deleting the wrong file.
-
They simplify creation of test and development databases.
You can minimize the time spent making decisions regarding file structure and naming, and you have fewer file management tasks. You can focus better on meeting the actual requirements of your test or development database.
-
Oracle Managed Files make development of portable third-party tools easier.
Oracle Managed Files eliminate the need to put operating system specific file names in SQL scripts.
Parent topic: About Oracle Managed Files
17.1.6 Oracle Managed Files and Existing Functionality
Using Oracle Managed Files does not eliminate any existing functionality.
Existing databases are able to operate as they always have. New files can be created as managed files while old ones are administered in the old way. Thus, a database can have a mixture of Oracle managed and unmanaged files.
Parent topic: About Oracle Managed Files
17.2 Enabling the Creation and Use of Oracle Managed Files
You set certain initialization parameters to enable and use Oracle Managed Files.
- Initialization Parameters That Enable Oracle Managed Files
The following table lists the initialization parameters that enable the use of Oracle Managed Files. - Setting the DB_CREATE_FILE_DEST Initialization Parameter
TheDB_CREATE_FILE_DEST
initialization parameter specifies the location of important database files. - Setting the DB_RECOVERY_FILE_DEST Parameter
Include theDB_RECOVERY_FILE_DEST
andDB_RECOVERY_FILE_DEST_SIZE
parameters in your initialization parameter file to identify the default location for the Fast Recovery Area. - Setting the DB_CREATE_ONLINE_LOG_DEST_n Initialization Parameters
TheDB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters specify the locations of the redo log files and the control files.
Parent topic: Using Oracle Managed Files
17.2.1 Initialization Parameters That Enable Oracle Managed Files
The following table lists the initialization parameters that enable the use of Oracle Managed Files.
The file system directories specified by these parameters must already exist; the database does not create them. The directory must also have permissions to allow the database to create the files in it.
The default location is used whenever a location is not explicitly specified for the operation creating the file. The database creates the file name, and a file thus created is an Oracle managed file.
Both of these initialization parameters are dynamic, and can be set using the ALTER SYSTEM
or ALTER SESSION
statement.
See Also:
-
Oracle Database Reference for additional information about initialization parameters
Parent topic: Enabling the Creation and Use of Oracle Managed Files
17.2.2 Setting the DB_CREATE_FILE_DEST Initialization Parameter
The DB_CREATE_FILE_DEST
initialization parameter specifies the location of important database files.
Include the DB_CREATE_FILE_DEST
initialization parameter in your initialization parameter file to identify the default location for the database server to create:
-
Data files
-
Temp files
-
Redo log files
-
Control files
-
Block change tracking files
You specify the name of a file system directory that becomes the default location for the creation of the operating system files for these entities. The following example sets /u01/app/oracle/oradata
as the default directory to use when creating Oracle Managed Files:
DB_CREATE_FILE_DEST = '/u01/app/oracle/oradata'
Parent topic: Enabling the Creation and Use of Oracle Managed Files
17.2.3 Setting the DB_RECOVERY_FILE_DEST Parameter
Include the DB_RECOVERY_FILE_DEST
and DB_RECOVERY_FILE_DEST_SIZE
parameters in your initialization parameter file to identify the default location for the Fast Recovery Area.
The Fast Recovery Area contains:
-
Redo log files or multiplexed copies of redo log files
-
Control files or multiplexed copies of control files
-
RMAN backups (data file copies, control file copies, backup pieces, control file autobackups)
-
Archived logs
-
Flashback logs
You specify the name of file system directory that becomes the default location for creation of the operating system files for these entities. For example:
DB_RECOVERY_FILE_DEST = '/u01/app/oracle/fast_recovery_area' DB_RECOVERY_FILE_DEST_SIZE = 20G
Parent topic: Enabling the Creation and Use of Oracle Managed Files
17.2.4 Setting the DB_CREATE_ONLINE_LOG_DEST_n Initialization Parameters
The DB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters specify the locations of the redo log files and the control files.
Include the DB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters in your initialization parameter file to identify the default locations for the database server to create:
-
Redo log files
-
Control files
You specify the name of a file system directory or Oracle ASM disk group that becomes the default location for the creation of the files for these entities. You can specify up to five multiplexed locations.
For the creation of redo log files and control files only, this parameter overrides any default location specified in the DB_CREATE_FILE_DEST
and DB_RECOVERY_FILE_DEST
initialization parameters. If you do not specify a DB_CREATE_FILE_DEST
parameter, but you do specify the DB_CREATE_ONLINE_LOG_DEST_
n
parameter, then only redo log files and control files can be created as Oracle Managed Files.
It is recommended that you specify at least two parameters. For example:
DB_CREATE_ONLINE_LOG_DEST_1 = '/u02/oradata' DB_CREATE_ONLINE_LOG_DEST_2 = '/u03/oradata'
This allows multiplexing, which provides greater fault-tolerance for the redo log and control file if one of the destinations fails.
Parent topic: Enabling the Creation and Use of Oracle Managed Files
17.3 Creating Oracle Managed Files
You can use Oracle Managed Files to create data files, temp files, control files, redo log files, and archived log.
- When Oracle Database Creates Oracle Managed Files
Oracle Database creates Oracle Managed Files when certain conditions are met. - How Oracle Managed Files Are Named
The file names of Oracle Managed Files comply with the Optimal Flexible Architecture (OFA) standard for file naming. - Creating Oracle Managed Files at Database Creation
TheCREATE DATABASE
statement can perform actions related to Oracle Managed Files. - Creating Data Files for Tablespaces Using Oracle Managed Files
Oracle Database can create data files for tablespaces using Oracle Managed Files when certain conditions are met. - Creating Temp Files for Temporary Tablespaces Using Oracle Managed Files
Oracle Database can create temp files for temporary tablespaces using Oracle Managed Files when certain conditions are met. - Creating Control Files Using Oracle Managed Files
Oracle Database can create control files using Oracle Managed Files when certain conditions are met. - Creating Redo Log Files Using Oracle Managed Files
Redo log files are created at database creation time. They can also be created when you issue either of the following statements:ALTER DATABASE ADD LOGFILE
andALTER DATABASE OPEN RESETLOGS
. - Creating Archived Logs Using Oracle Managed Files
Archived logs are created by a background process or by a SQL statement.
Parent topic: Using Oracle Managed Files
17.3.1 When Oracle Database Creates Oracle Managed Files
Oracle Database creates Oracle Managed Files when certain conditions are met.
If you have met any of the following conditions, then Oracle Database creates Oracle Managed Files for you, as appropriate, when no file specification is given in the create operation:
-
You have included any of the
DB_CREATE_FILE_DEST
,DB_RECOVERY_FILE_DEST
, orDB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters in your initialization parameter file. -
You have issued the
ALTER SYSTEM
statement to dynamically set any ofDB_RECOVERY_FILE_DEST
,DB_CREATE_FILE_DEST
, orDB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters -
You have issued the
ALTER SESSION
statement to dynamically set any of theDB_CREATE_FILE_DEST
,DB_RECOVERY_FILE_DEST
, orDB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters.
If a statement that creates an Oracle managed file finds an error or does not complete due to some failure, then any Oracle Managed Files created by the statement are automatically deleted as part of the recovery of the error or failure. However, because of the large number of potential errors that can occur with file systems and storage subsystems, there can be situations where you must manually remove the files using operating system commands.
Parent topic: Creating Oracle Managed Files
17.3.2 How Oracle Managed Files Are Named
The file names of Oracle Managed Files comply with the Optimal Flexible Architecture (OFA) standard for file naming.
Note:
The naming scheme described in this section applies only to files created in operating system file systems. The naming scheme for files created in Oracle Automatic Storage Management (Oracle ASM) disk groups is described in Oracle Automatic Storage Management Administrator's Guide.
The assigned names are intended to meet the following requirements:
-
Database files are easily distinguishable from all other files.
-
Files of one database type are easily distinguishable from other database types.
-
Files are clearly associated with important attributes specific to the file type. For example, a data file name may include the tablespace name to allow for easy association of data file to tablespace, or an archived log name may include the thread, sequence, and creation date.
No two Oracle Managed Files are given the same name. The name that is used for creation of an Oracle managed file is constructed from three sources:
-
The default creation location
-
A file name template that is chosen based on the type of the file. The template also depends on the operating system platform and whether or not Oracle Automatic Storage Management is used.
-
A unique string created by Oracle Database or the operating system. This ensures that file creation does not damage an existing file and that the file cannot be mistaken for some other file.
As a specific example, file names for Oracle Managed Files have the following format on a Solaris file system:
destination_prefix/o1_mf_%t_%u_.dbf
where:
-
destination_prefix
isdestination_location
/db_unique_name
/datafile
where:
-
destination_location
is the location specified inDB_CREATE_FILE_DEST
-
db_unique_name
is the globally unique name (DB_UNIQUE_NAME
initialization parameter) of the target database. If there is noDB_UNIQUE_NAME
parameter, then theDB_NAME
initialization parameter value is used.
-
-
%t is the tablespace name.
-
%u is an eight-character string that guarantees uniqueness
For example, assume the following parameter settings:
DB_CREATE_FILE_DEST = /u01/app/oracle/oradata DB_UNIQUE_NAME = PAYROLL
Then an example data file name would be:
/u01/app/oracle/oradata/PAYROLL/datafile/o1_mf_tbs1_2ixh90q_.dbf
Names for other file types are similar. Names on other platforms are also similar, subject to the constraints of the naming rules of the platform.
The examples on the following pages use Oracle managed file names as they might appear with a Solaris file system as an OMF destination.
Note:
Do not rename an Oracle managed file. The database identifies an Oracle managed file based on its name. If you rename the file, the database is no longer able to recognize it as an Oracle managed file and will not manage the file accordingly.
Parent topic: Creating Oracle Managed Files
17.3.3 Creating Oracle Managed Files at Database Creation
The CREATE DATABASE
statement can perform actions related to Oracle Managed Files.
Note:
The rules and defaults in this section also apply to creating a database with Database Configuration Assistant (DBCA). With DBCA, you use a graphical interface to enable Oracle Managed Files and to specify file locations that correspond to the initialization parameters described in this section.
- Specifying Control Files at Database Creation
At database creation, the control file is created in the files specified by theCONTROL_FILES
initialization parameter. - Specifying Redo Log Files at Database Creation
TheLOGFILE
clause is not required in theCREATE DATABASE
statement, and omitting it provides a simple means of creating Oracle managed redo log files. - Specifying the SYSTEM and SYSAUX Tablespace Data Files at Database Creation
TheDATAFILE
orSYSAUX
DATAFILE
clause is not required in theCREATE DATABASE
statement, and omitting it provides a simple means of creating Oracle managed data files for theSYSTEM
andSYSAUX
tablespaces. - Specifying the Undo Tablespace Data File at Database Creation
TheDATAFILE
subclause of theUNDO TABLESPACE
clause is optional and a file name is not required in the file specification. - Specifying the Default Temporary Tablespace Temp File at Database Creation
TheTEMPFILE
subclause is optional for theDEFAULT TEMPORARY TABLESPACE
clause and a file name is not required in the file specification. - CREATE DATABASE Statement Using Oracle Managed Files: Examples
Examples illustrate creating a database with theCREATE DATABASE
statement when using the Oracle Managed Files feature.
See Also:
Oracle Database SQL Language Reference for a description of the CREATE DATABASE
statement
Parent topic: Creating Oracle Managed Files
17.3.3.1 Specifying Control Files at Database Creation
At database creation, the control file is created in the files specified by the CONTROL_FILES
initialization parameter.
If the CONTROL_FILES
parameter is not set and at least one of the initialization parameters required for the creation of Oracle Managed Files is set, then an Oracle managed control file is created in the default control file destinations. In order of precedence, the default destination is defined as follows:
-
One or more control files as specified in the
DB_CREATE_ONLINE_LOG_DEST_
n
initialization parameter. The file in the first directory is the primary control file. WhenDB_CREATE_ONLINE_LOG_DEST_
n
is specified, the database does not create a control file inDB_CREATE_FILE_DEST
or inDB_RECOVERY_FILE_DEST
(the Fast Recovery Area). -
If no value is specified for
DB_CREATE_ONLINE_LOG_DEST_
n
, but values are set for both theDB_CREATE_FILE_DEST
andDB_RECOVERY_FILE_DEST
, then the database creates one control file in each location. The location specified inDB_CREATE_FILE_DEST
is the primary control file. -
If a value is specified only for
DB_CREATE_FILE_DEST
, then the database creates one control file in that location. -
If a value is specified only for
DB_RECOVERY_FILE_DEST
, then the database creates one control file in that location.
If the CONTROL_FILES
parameter is not set and none of these initialization parameters are set, then the Oracle Database default action is operating system dependent. At least one copy of a control file is created in an operating system dependent default location. Any copies of control files created in this fashion are not Oracle Managed Files, and you must add a CONTROL_FILES
initialization parameter to any initialization parameter file.
If the database creates an Oracle managed control file, and if there is a server parameter file, then the database creates a CONTROL_FILES
initialization parameter entry in the server parameter file. If there is no server parameter file, then you must manually include a CONTROL_FILES
initialization parameter entry in the text initialization parameter file.
See Also:
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.3.2 Specifying Redo Log Files at Database Creation
The LOGFILE
clause is not required in the CREATE DATABASE
statement, and omitting it provides a simple means of creating Oracle managed redo log files.
If the LOGFILE
clause is omitted, then redo log files are created in the default redo log file destinations. In order of precedence, the default destination is defined as follows:
-
If either the
DB_CREATE_ONLINE_LOG_DEST_
n
is set, then the database creates a log file member in each directory specified, up to the value of theMAXLOGMEMBERS
initialization parameter. -
If the
DB_CREATE_ONLINE_LOG_DEST_
n
parameter is not set, but both theDB_CREATE_FILE_DEST
andDB_RECOVERY_FILE_DEST
initialization parameters are set, then the database creates one Oracle managed log file member in each of those locations. The log file in theDB_CREATE_FILE_DEST
destination is the first member. -
If only the
DB_CREATE_FILE_DEST
initialization parameter is specified, then the database creates a log file member in that location. -
If only the
DB_RECOVERY_FILE_DEST
initialization parameter is specified, then the database creates a log file member in that location.
The default size of an Oracle managed redo log file is 100 MB.
Optionally, you can create Oracle managed redo log files, and override default attributes, by including the LOGFILE
clause but omitting a file name. Redo log files are created the same way, except for the following: If no file name is provided in the LOGFILE
clause of CREATE DATABASE
, and none of the initialization parameters required for creating Oracle Managed Files are provided, then the CREATE DATABASE
statement fails.
See Also:
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.3.3 Specifying the SYSTEM and SYSAUX Tablespace Data Files at Database Creation
The DATAFILE
or SYSAUX
DATAFILE
clause is not required in the CREATE DATABASE
statement, and omitting it provides a simple means of creating Oracle managed data files for the SYSTEM
and SYSAUX
tablespaces.
If the DATAFILE
clause is omitted, then one of the following actions occurs:
-
If
DB_CREATE_FILE_DEST
is set, then one Oracle managed data file for theSYSTEM
tablespace and another for theSYSAUX
tablespace are created in theDB_CREATE_FILE_DEST
directory. -
If
DB_CREATE_FILE_DEST
is not set, then the database creates oneSYSTEM
and oneSYSAUX
tablespace data file whose names and sizes are operating system dependent. AnySYSTEM
orSYSAUX
tablespace data file created in this manner is not an Oracle managed file.
By default, Oracle managed data files, including those for the SYSTEM
and SYSAUX
tablespaces, are 100MB and autoextensible. When autoextension is required, the database extends the data file by its existing size or 100 MB, whichever is smaller. You can also explicitly specify the autoextensible unit using the NEXT
parameter of the STORAGE
clause when you specify the data file (in a CREATE
or ALTER TABLESPACE
operation).
Optionally, you can create an Oracle managed data file for the SYSTEM
or SYSAUX
tablespace and override default attributes. This is done by including the DATAFILE
clause, omitting a file name, but specifying overriding attributes. When a file name is not supplied and the DB_CREATE_FILE_DEST
parameter is set, an Oracle managed data file for the SYSTEM
or SYSAUX
tablespace is created in the DB_CREATE_FILE_DEST
directory with the specified attributes being overridden. However, if a file name is not supplied and the DB_CREATE_FILE_DEST
parameter is not set, then the CREATE DATABASE
statement fails.
When overriding the default attributes of an Oracle managed file, if a SIZE
value is specified but no AUTOEXTEND
clause is specified, then the data file is not autoextensible.
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.3.4 Specifying the Undo Tablespace Data File at Database Creation
The DATAFILE
subclause of the UNDO TABLESPACE
clause is optional and a file name is not required in the file specification.
If a file name is not supplied and the DB_CREATE_FILE_DEST
parameter is set, then an Oracle managed data file is created in the DB_CREATE_FILE_DEST
directory. If DB_CREATE_FILE_DEST
is not set, then the statement fails with a syntax error.
The UNDO TABLESPACE
clause itself is optional in the CREATE DATABASE
statement. If it is not supplied, and automatic undo management mode is enabled (the default), then a default undo tablespace named SYS_UNDOTS
is created and a 20 MB data file that is autoextensible is allocated as follows:
-
If
DB_CREATE_FILE_DEST
is set, then an Oracle managed data file is created in the indicated directory. -
If
DB_CREATE_FILE_DEST
is not set, then the data file location is operating system specific.See Also:
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.3.5 Specifying the Default Temporary Tablespace Temp File at Database Creation
The TEMPFILE
subclause is optional for the DEFAULT TEMPORARY TABLESPACE
clause and a file name is not required in the file specification.
If a file name is not supplied and the DB_CREATE_FILE_DEST
parameter set, then an Oracle managed temp file is created in the DB_CREATE_FILE_DEST
directory. If DB_CREATE_FILE_DEST
is not set, then the CREATE DATABASE
statement fails with a syntax error.
The DEFAULT TEMPORARY TABLESPACE
clause itself is optional. If it is not specified, then no default temporary tablespace is created.
The default size for an Oracle managed temp file is 100 MB and the file is autoextensible with an unlimited maximum size.
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.3.6 CREATE DATABASE Statement Using Oracle Managed Files: Examples
Examples illustrate creating a database with the CREATE DATABASE
statement when using the Oracle Managed Files feature.
CREATE DATABASE: Example 1
This example creates a database with the following Oracle Managed Files:
-
A
SYSTEM
tablespace data file in directory/u01/app/oracle/oradata
that is autoextensible up to an unlimited size. -
A
SYSAUX
tablespace data file in directory/u01/app/oracle/oradata
that is autoextensible up to an unlimited size. The tablespace is locally managed with automatic segment-space management.
-
Two online log groups with two members of 100 MB each, one each in
/u02/oradata
and/u03/oradata.
-
If automatic undo management mode is enabled (the default), then an undo tablespace data file in directory
/u01/app/oracle/oradata
that is 20 MB and autoextensible up to an unlimited size. An undo tablespace namedSYS_UNDOTS
is created. -
If no
CONTROL_FILES
initialization parameter is specified, then two control files, one each in/u02/oradata
and/u03/oradata
. The control file in/u02/oradata
is the primary control file.
The following parameter settings relating to Oracle Managed Files, are included in the initialization parameter file:
DB_CREATE_FILE_DEST = '/u01/app/oracle/oradata' DB_CREATE_ONLINE_LOG_DEST_1 = '/u02/oradata' DB_CREATE_ONLINE_LOG_DEST_2 = '/u03/oradata'
The following statement is issued at the SQL prompt:
CREATE DATABASE sample;
To create the database with a locally managed SYSTEM
tablespace, add the EXTENT
MANAGEMENT
LOCAL
clause:
CREATE DATABASE sample EXTENT MANAGEMENT LOCAL;
Without this clause, the SYSTEM
tablespace is dictionary managed. Oracle recommends that you create a locally managed SYSTEM
tablespace.
CREATE DATABASE: Example 2
This example creates a database with the following Oracle Managed Files:
-
A
SYSTEM
tablespace data file in directory/u01/app/oracle/oradata
that is autoextensible up to an unlimited size. -
A
SYSAUX
tablespace data file in directory/u01/app/oracle/oradata
that is autoextensible up to an unlimited size. The tablespace is locally managed with automatic segment-space management.
-
Two redo log files of 100 MB each in directory
/u01/app/oracle/oradata.
They are not multiplexed. -
An undo tablespace data file in directory
/u01/app/oracle/oradata
that is 20 MB and autoextensible up to an unlimited size. An undo tablespace namedSYS_UNDOTS
is created. -
A control file in
/u01/app/oracle/oradata
.
In this example, it is assumed that:
-
No
DB_CREATE_ONLINE_LOG_DEST_
n
initialization parameters are specified in the initialization parameter file. -
No
CONTROL_FILES
initialization parameter was specified in the initialization parameter file. -
Automatic undo management mode is enabled.
The following statements are issued at the SQL prompt:
ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u01/app/oracle/oradata'; CREATE DATABASE sample2 EXTENT MANAGEMENT LOCAL;
This database configuration is not recommended for a production database. The example illustrates how a very low-end database or simple test database can easily be created. To better protect this database from failures, at least one more control file should be created and the redo log should be multiplexed.
CREATE DATABASE: Example 3
In this example, the file size for the Oracle Managed Files for the default temporary tablespace and undo tablespace are specified. A database with the following Oracle Managed Files is created:
-
A 400 MB
SYSTEM
tablespace data file in directory/u01/app/oracle/oradata
. BecauseSIZE
is specified, the file in not autoextensible. -
A 200 MB
SYSAUX
tablespace data file in directory/u01/app/oracle/oradata.
BecauseSIZE
is specified, the file in not autoextensible. The tablespace is locally managed with automatic segment-space management. -
Two redo log groups with two members of 100 MB each, one each in directories
/u02/oradata
and/u03/oradata.
-
For the default temporary tablespace
dflt_ts
, a 10 MB temp file in directory/u01/app/oracle/oradata
. BecauseSIZE
is specified, the file in not autoextensible. -
For the undo tablespace
undo_ts
, a 100 MB data file in directory/u01/app/oracle/oradata
. BecauseSIZE
is specified, the file is not autoextensible. -
If no
CONTROL_FILES
initialization parameter was specified, then two control files, one each in directories/u02/oradata
and/u03/oradata
. The control file in/u02/oradata
is the primary control file.
The following parameter settings are included in the initialization parameter file:
DB_CREATE_FILE_DEST = '/u01/app/oracle/oradata' DB_CREATE_ONLINE_LOG_DEST_1 = '/u02/oradata' DB_CREATE_ONLINE_LOG_DEST_2 = '/u03/oradata'
The following statement is issued at the SQL prompt:
CREATE DATABASE sample3 EXTENT MANAGEMENT LOCAL DATAFILE SIZE 400M SYSAUX DATAFILE SIZE 200M DEFAULT TEMPORARY TABLESPACE dflt_ts TEMPFILE SIZE 10M UNDO TABLESPACE undo_ts DATAFILE SIZE 100M;
See Also:
Parent topic: Creating Oracle Managed Files at Database Creation
17.3.4 Creating Data Files for Tablespaces Using Oracle Managed Files
Oracle Database can create data files for tablespaces using Oracle Managed Files when certain conditions are met.
- About Creating Data Files for Tablespaces Using Oracle Managed Files
When certain conditions are met, the following SQL statements can create data files for tablespaces using Oracle Managed Files:CREATE TABLESPACE
,CREATE UNDO TABLESPACE
, andALTER TABLESPACE ... ADD DATAFILE
. - CREATE TABLESPACE: Examples
Examples illustrate creating tablespaces with Oracle Managed Files. - CREATE UNDO TABLESPACE: Example
An example illustrates creating an undo tablespace. - ALTER TABLESPACE: Example
An example illustrates adding an Oracle managed autoextensible data file to a tablespace.
Parent topic: Creating Oracle Managed Files
17.3.4.1 About Creating Data Files for Tablespaces Using Oracle Managed Files
When certain conditions are met, the following SQL statements can create data files for tablespaces using Oracle Managed Files: CREATE TABLESPACE
, CREATE UNDO TABLESPACE
, and ALTER TABLESPACE ... ADD DATAFILE
.
The following statements can create data files:
-
CREATE
TABLESPACE
-
CREATE
UNDO
TABLESPACE
-
ALTER
TABLESPACE
...ADD
DATAFILE
When creating a tablespace, either a permanent tablespace or an undo tablespace, the DATAFILE
clause is optional. When you include the DATAFILE
clause, the file name is optional. If the DATAFILE
clause or file name is not provided, then the following rules apply:
-
If the
DB_CREATE_FILE_DEST
initialization parameter is specified, then an Oracle managed data file is created in the location specified by the parameter. -
If the
DB_CREATE_FILE_DEST
initialization parameter is not specified, then the statement creating the data file fails.
When you add a data file to a tablespace with the ALTER TABLESPACE...ADD DATAFILE
statement the file name is optional. If the file name is not specified, then the same rules apply as discussed in the previous paragraph.
By default, an Oracle managed data file for a permanent tablespace is 100 MB and is autoextensible with an unlimited maximum size. However, if in your DATAFILE
clause you override these defaults by specifying a SIZE
value (and no AUTOEXTEND
clause), then the data file is not autoextensible.
17.3.4.2 CREATE TABLESPACE: Examples
Examples illustrate creating tablespaces with Oracle Managed Files.
See Also:
Oracle Database SQL Language Reference for a description of the CREATE TABLESPACE
statement
CREATE TABLESPACE: Example 1
The following example sets the default location for data file creations to /u01/oradata
and then creates a tablespace tbs_1
with a data file in that location. The data file is 100 MB and is autoextensible with an unlimited maximum size.
SQL> ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u01/oradata'; SQL> CREATE TABLESPACE tbs_1;
CREATE TABLESPACE: Example 2
This example creates a tablespace named tbs_2
with a data file in the directory /u01/oradata
. The data file initial size is 400 MB, and because the SIZE clause is specified, the data file is not autoextensible.
The following parameter setting is included in the initialization parameter file:
DB_CREATE_FILE_DEST = '/u01/oradata'
The following statement is issued at the SQL prompt:
SQL> CREATE TABLESPACE tbs_2 DATAFILE SIZE 400M;
CREATE TABLESPACE: Example 3
This example creates a tablespace named tbs_3
with an autoextensible data file in the directory /u01/oradata
with a maximum size of 800 MB and an initial size of 100 MB:
The following parameter setting is included in the initialization parameter file:
DB_CREATE_FILE_DEST = '/u01/oradata'
The following statement is issued at the SQL prompt:
SQL> CREATE TABLESPACE tbs_3 DATAFILE AUTOEXTEND ON MAXSIZE 800M;
CREATE TABLESPACE: Example 4
The following example sets the default location for data file creations to /u01/oradata
and then creates a tablespace named tbs_4
in that directory with two data files. Both data files have an initial size of 200 MB, and because a SIZE
value is specified, they are not autoextensible
SQL> ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u01/oradata'; SQL> CREATE TABLESPACE tbs_4 DATAFILE SIZE 200M, SIZE 200M;
17.3.4.3 CREATE UNDO TABLESPACE: Example
An example illustrates creating an undo tablespace.
The following example creates an undo tablespace named undotbs_1
with a data file in the directory /u01/oradata
. The data file for the undo tablespace is 100 MB and is autoextensible with an unlimited maximum size.
-
Set the following initialization parameter:
DB_CREATE_FILE_DEST = '/u01/oradata'
-
Issue the following SQL statement:
SQL> CREATE UNDO TABLESPACE undotbs_1;
See Also:
Oracle Database SQL Language Reference for a description of the CREATE UNDO TABLESPACE
statement
17.3.4.4 ALTER TABLESPACE: Example
An example illustrates adding an Oracle managed autoextensible data file to a tablespace.
This example adds an Oracle managed autoextensible data file to the tbs_1
tablespace. The data file has an initial size of 100 MB and a maximum size of 800 MB.
-
Set the following initialization parameter:
DB_CREATE_FILE_DEST = '/u01/oradata'
-
Issue the following SQL statement:
SQL> ALTER TABLESPACE tbs_1 ADD DATAFILE AUTOEXTEND ON MAXSIZE 800M;
See Also:
Oracle Database SQL Language Reference for a description of the ALTER TABLESPACE
statement
17.3.5 Creating Temp Files for Temporary Tablespaces Using Oracle Managed Files
Oracle Database can create temp files for temporary tablespaces using Oracle Managed Files when certain conditions are met.
- About Creating Temp Files for Temporary Tablespaces Using Oracle Managed Files
When certain conditions are met, the following SQL statements can create temp files for tablespaces using Oracle Managed Files:CREATE TEMPORARY TABLESPACE
andALTER TABLESPACE ... ADD TEMPFILE
. - CREATE TEMPORARY TABLESPACE: Example
An example illustrates creating a temporary tablespace. - ALTER TABLESPACE... ADD TEMPFILE: Example
An example illustrates adding a temp file to a temporary tablespace.
Parent topic: Creating Oracle Managed Files
17.3.5.1 About Creating Temp Files for Temporary Tablespaces Using Oracle Managed Files
When certain conditions are met, the following SQL statements can create temp files for tablespaces using Oracle Managed Files: CREATE TEMPORARY TABLESPACE
and ALTER TABLESPACE ... ADD TEMPFILE
.
The following statements that create temp files are relevant to the discussion in this section:
-
CREATE
TEMPORARY
TABLESPACE
-
ALTER
TABLESPACE
...ADD
TEMPFILE
When creating a temporary tablespace the TEMPFILE
clause is optional. If you include the TEMPFILE
clause, then the file name is optional. If the TEMPFILE
clause or file name is not provided, then the following rules apply:
-
If the
DB_CREATE_FILE_DEST
initialization parameter is specified, then an Oracle managed temp file is created in the location specified by the parameter. -
If the
DB_CREATE_FILE_DEST
initialization parameter is not specified, then the statement creating the temp file fails.
When you add a temp file to a tablespace with the ALTER TABLESPACE...ADD TEMPFILE
statement the file name is optional. If the file name is not specified, then the same rules apply as discussed in the previous paragraph.
When overriding the default attributes of an Oracle managed file, if a SIZE
value is specified but no AUTOEXTEND
clause is specified, then the data file is not autoextensible.
17.3.5.2 CREATE TEMPORARY TABLESPACE: Example
An example illustrates creating a temporary tablespace.
The following example sets the default location for data file creations to /u01/oradata
and then creates a tablespace named temptbs_1
with a temp file in that location. The temp file is 100 MB and is autoextensible with an unlimited maximum size.
SQL> ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u01/oradata'; SQL> CREATE TEMPORARY TABLESPACE temptbs_1;
See Also:
Oracle Database SQL Language Reference for a description of the CREATE TABLESPACE
statement
17.3.5.3 ALTER TABLESPACE... ADD TEMPFILE: Example
An example illustrates adding a temp file to a temporary tablespace.
The following example sets the default location for data file creations to /u03/oradata
and then adds a temp file in the default location to a tablespace named temptbs_1
. The temp file initial size is 100 MB. It is autoextensible with an unlimited maximum size.
SQL> ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u03/oradata'; SQL> ALTER TABLESPACE TBS_1 ADD TEMPFILE;
See Also:
Oracle Database SQL Language Reference for a description of the ALTER TABLESPACE
statement
17.3.6 Creating Control Files Using Oracle Managed Files
Oracle Database can create control files using Oracle Managed Files when certain conditions are met.
- About Creating Control Files Using Oracle Managed Files
When certain conditions are met, theCREATE CONTROLFILE
SQL statements can create control files using Oracle Managed Files. - CREATE CONTROLFILE Using NORESETLOGS Keyword: Example
An example illustrates creating a control file using theCREATE CONTROLFILE
statement with theNORESETLOGS
keyword. - CREATE CONTROLFILE Using RESETLOGS Keyword: Example
An example illustrates creating a control file using theCREATE CONTROLFILE
statement with theRESETLOGS
keyword.
Parent topic: Creating Oracle Managed Files
17.3.6.1 About Creating Control Files Using Oracle Managed Files
When certain conditions are met, the CREATE CONTROLFILE
SQL statements can create control files using Oracle Managed Files.
When you issue the CREATE CONTROLFILE
statement, a control file is created (or reused, if REUSE
is specified) in the files specified by the CONTROL_FILES
initialization parameter. If the CONTROL_FILES
parameter is not set, then the control file is created in the default control file destinations. The default destination is determined according to the precedence documented in "Specifying Control Files at Database Creation".
If Oracle Database creates an Oracle managed control file, and there is a server parameter file, then the database creates a CONTROL_FILES
initialization parameter for the server parameter file. If there is no server parameter file, then you must create a CONTROL_FILES
initialization parameter manually and include it in the initialization parameter file.
If the data files in the database are Oracle Managed Files, then the database-generated file names for the files must be supplied in the DATAFILE
clause of the statement.
If the redo log files are Oracle Managed Files, then the NORESETLOGS
or RESETLOGS
keyword determines what can be supplied in the LOGFILE
clause:
-
If the
NORESETLOGS
keyword is used, then the database-generated file names for the Oracle managed redo log files must be supplied in theLOGFILE
clause. -
If the
RESETLOGS
keyword is used, then the redo log file names can be supplied as with theCREATE DATABASE
statement. See "Specifying Redo Log Files at Database Creation".
The sections that follow contain examples of using the CREATE CONTROLFILE
statement with Oracle Managed Files.
See Also:
-
Oracle Database SQL Language Reference for a description of the
CREATE CONTROLFILE
statement
Parent topic: Creating Control Files Using Oracle Managed Files
17.3.6.2 CREATE CONTROLFILE Using NORESETLOGS Keyword: Example
An example illustrates creating a control file using the CREATE CONTROLFILE
statement with the NORESETLOGS
keyword.
The following CREATE CONTROLFILE
statement is generated by an ALTER DATABASE BACKUP CONTROLFILE TO TRACE
statement for a database with Oracle managed data files and redo log files:
CREATE CONTROLFILE DATABASE sample LOGFILE GROUP 1 ('/u01/oradata/SAMPLE/onlinelog/o1_mf_1_o220rtt9_.log', '/u02/oradata/SAMPLE/onlinelog/o1_mf_1_v2o0b2i3_.log') SIZE 100M, GROUP 2 ('/u01/oradata/SAMPLE/onlinelog/o1_mf_2_p22056iw_.log', '/u02/oradata/SAMPLE/onlinelog/o1_mf_2_p02rcyg3_.log') SIZE 100M NORESETLOGS DATAFILE '/u01/oradata/SAMPLE/datafile/o1_mf_system_xu34ybm2_.dbf' SIZE 100M, '/u01/oradata/SAMPLE/datafile/o1_mf_sysaux_aawbmz51_.dbf' SIZE 100M, '/u01/oradata/SAMPLE/datafile/o1_mf_sys_undo_apqbmz51_.dbf' SIZE 100M MAXLOGFILES 5 MAXLOGHISTORY 100 MAXDATAFILES 10 MAXINSTANCES 2 ARCHIVELOG;
Parent topic: Creating Control Files Using Oracle Managed Files
17.3.6.3 CREATE CONTROLFILE Using RESETLOGS Keyword: Example
An example illustrates creating a control file using the CREATE CONTROLFILE
statement with the RESETLOGS
keyword.
The following is an example of a CREATE CONTROLFILE
statement with the RESETLOGS
option. Some combination of DB_CREATE_FILE_DEST
, DB_RECOVERY_FILE_DEST
, and DB_CREATE_ONLINE_LOG_DEST_
n
or must be set.
CREATE CONTROLFILE DATABASE sample RESETLOGS DATAFILE '/u01/oradata/SAMPLE/datafile/o1_mf_system_aawbmz51_.dbf', '/u01/oradata/SAMPLE/datafile/o1_mf_sysaux_axybmz51_.dbf', '/u01/oradata/SAMPLE/datafile/o1_mf_sys_undo_azzbmz51_.dbf' SIZE 100M MAXLOGFILES 5 MAXLOGHISTORY 100 MAXDATAFILES 10 MAXINSTANCES 2 ARCHIVELOG;
Later, you must issue the ALTER DATABASE OPEN RESETLOGS
statement to re-create the redo log files. This is discussed in "Using the ALTER DATABASE OPEN RESETLOGS Statement". If the previous log files are Oracle Managed Files, then they are not deleted.
Parent topic: Creating Control Files Using Oracle Managed Files
17.3.7 Creating Redo Log Files Using Oracle Managed Files
Redo log files are created at database creation time. They can also be created when you issue either of the following statements: ALTER DATABASE ADD LOGFILE
and ALTER DATABASE OPEN RESETLOGS
.
- Using the ALTER DATABASE ADD LOGFILE Statement
TheALTER DATABASE ADD LOGFILE
statement lets you later add a new group to your current redo log. - Using the ALTER DATABASE OPEN RESETLOGS Statement
If you previously created a control file specifyingRESETLOGS
and either did not specify file names or specified nonexistent file names, then the database creates redo log files for you when you issue theALTER DATABASE OPEN RESETLOGS
statement.
See Also:
Oracle Database SQL Language Reference for a description of the ALTER DATABASE
statement
Parent topic: Creating Oracle Managed Files
17.3.7.1 Using the ALTER DATABASE ADD LOGFILE Statement
The ALTER DATABASE ADD LOGFILE
statement lets you later add a new group to your current redo log.
The file name in the ADD LOGFILE
clause is optional if you are using Oracle Managed Files. If a file name is not provided, then a redo log file is created in the default log file destination. The default destination is determined according to the precedence documented in "Specifying Redo Log Files at Database Creation".
If a file name is not provided and you have not provided one of the initialization parameters required for creating Oracle Managed Files, then the statement returns an error.
The default size for an Oracle managed log file is 100 MB.
You continue to add and drop redo log file members by specifying complete file names.
Adding New Redo Log Files: Example
The following example creates a log group with a member in /u01/oradata
and another member in /u02/oradata
. The size of each log file is 100 MB.
The following parameter settings are included in the initialization parameter file:
DB_CREATE_ONLINE_LOG_DEST_1 = '/u01/oradata' DB_CREATE_ONLINE_LOG_DEST_2 = '/u02/oradata'
The following statement is issued at the SQL prompt:
SQL> ALTER DATABASE ADD LOGFILE;
Parent topic: Creating Redo Log Files Using Oracle Managed Files
17.3.7.2 Using the ALTER DATABASE OPEN RESETLOGS Statement
If you previously created a control file specifying RESETLOGS
and either did not specify file names or specified nonexistent file names, then the database creates redo log files for you when you issue the ALTER DATABASE OPEN RESETLOGS
statement.
The rules for determining the directories in which to store redo log files, when none are specified in the control file, are the same as those discussed in "Specifying Redo Log Files at Database Creation".
Parent topic: Creating Redo Log Files Using Oracle Managed Files
17.3.8 Creating Archived Logs Using Oracle Managed Files
Archived logs are created by a background process or by a SQL statement.
Archived logs are created in the DB_RECOVERY_FILE_DEST
location when:
-
The
ARC
orLGWR
background process archives an online redo log or -
An
ALTER SYSTEM ARCHIVE LOG CURRENT
statement is issued.
For example, assume that the following parameter settings are included in the initialization parameter file:
DB_RECOVERY_FILE_DEST_SIZE = 20G DB_RECOVERY_FILE_DEST = '/u01/oradata' LOG_ARCHIVE_DEST_1 = 'LOCATION=USE_DB_RECOVERY_FILE_DEST'
Parent topic: Creating Oracle Managed Files
17.4 Operation of Oracle Managed Files
The file names of Oracle Managed Files are accepted in SQL statements wherever a file name is used to identify an existing file.
These file names, like other file names, are stored in the control file and, if using Recovery Manager (RMAN) for backup and recovery, in the RMAN catalog. They are visible in all of the usual fixed and dynamic performance views that are available for monitoring data files and temp files (for example, V$DATAFILE
or DBA_DATA_FILES
).
The following are some examples of statements using database-generated file names:
SQL> ALTER DATABASE 2> RENAME FILE '/u01/oradata/mydb/datafile/o1_mf_tbs01_ziw3bopb_.dbf' 3> TO '/u01/oradata/mydb/tbs0101.dbf'; SQL> ALTER DATABASE 2> DROP LOGFILE '/u01/oradata/mydb/onlinelog/o1_mf_1_wo94n2xi_.log'; SQL> ALTER TABLE emp 2> ALLOCATE EXTENT 3> (DATAFILE '/u01/oradata/mydb/datafile/o1_mf_tbs1_2ixfh90q_.dbf');
You can backup and restore Oracle managed data files, temp files, and control files as you would corresponding non Oracle Managed Files. Using database-generated file names does not impact the use of logical backup files such as export files. This is particularly important for tablespace point-in-time recovery (TSPITR) and transportable tablespace export files.
There are some cases where Oracle Managed Files behave differently, including operations that drop files or rename file, and operations involving standby databases.
- Dropping Data Files and Temp Files
Unlike files that are not managed by the database, when an Oracle managed data file or temp file is dropped, the file name is removed from the control file and the file is automatically deleted from the file system. - Dropping Redo Log Files
When an Oracle managed redo log file is dropped, its Oracle Managed Files are deleted. You specify the group or members to be dropped. - Renaming Files
With Oracle Managed Files, SQL statements that rename files do not actually rename the files on the operating system, but rather, the names in the control file are changed. - Managing Standby Databases
The data files, control files, and redo log files in a standby database can be managed by the database. This is independent of whether Oracle Managed Files are used on the primary database.
Parent topic: Using Oracle Managed Files
17.4.1 Dropping Data Files and Temp Files
Unlike files that are not managed by the database, when an Oracle managed data file or temp file is dropped, the file name is removed from the control file and the file is automatically deleted from the file system.
The statements that delete Oracle Managed Files when they are dropped are:
-
DROP
TABLESPACE
-
ALTER
DATABASE
TEMPFILE
...DROP
You can also use these statements, which always delete files, Oracle managed or not:
-
ALTER
TABLESPACE
...DROP
DATAFILE
-
ALTER
TABLESPACE
...DROP
TEMPFILE
Parent topic: Operation of Oracle Managed Files
17.4.2 Dropping Redo Log Files
When an Oracle managed redo log file is dropped, its Oracle Managed Files are deleted. You specify the group or members to be dropped.
The following statements drop and delete redo log files:
-
ALTER
DATABASE
DROP
LOGFILE
-
ALTER
DATABASE
DROP
LOGFILE
MEMBER
Parent topic: Operation of Oracle Managed Files
17.4.3 Renaming Files
With Oracle Managed Files, SQL statements that rename files do not actually rename the files on the operating system, but rather, the names in the control file are changed.
The following statements are used to rename files:
-
ALTER
DATABASE
RENAME
FILE
-
ALTER
TABLESPACE
...RENAME
DATAFILE
If the old file is an Oracle managed file and it exists, then it is deleted. You must specify each file name using the conventions for file names on your operating system when you issue this statement.
Parent topic: Operation of Oracle Managed Files
17.4.4 Managing Standby Databases
The data files, control files, and redo log files in a standby database can be managed by the database. This is independent of whether Oracle Managed Files are used on the primary database.
When recovery of a standby database encounters redo for the creation of a data file, if the data file is an Oracle managed file, then the recovery process creates an empty file in the local default file system location. This allows the redo for the new file to be applied immediately without any human intervention.
When recovery of a standby database encounters redo for the deletion of a tablespace, it deletes any Oracle managed data files in the local file system. Note that this is independent of the INCLUDING DATAFILES
option issued at the primary database.
Parent topic: Operation of Oracle Managed Files
17.5 Scenarios for Using Oracle Managed Files
Scenarios illustrate how to use Oracle Managed Files.
- Scenario 1: Create and Manage a Database with Multiplexed Redo Logs
An example illustrates creating and managing a database with multiplexed redo logs. - Scenario 2: Create and Manage a Database with Database and Fast Recovery Areas
An example illustrates creating and managing a database with both database and fast recovery areas. - Scenario 3: Adding Oracle Managed Files to an Existing Database
An example illustrates adding Oracle Managed Files to an existing database.
Parent topic: Using Oracle Managed Files
17.5.1 Scenario 1: Create and Manage a Database with Multiplexed Redo Logs
An example illustrates creating and managing a database with multiplexed redo logs.
In this scenario, a DBA creates a database where the data files and redo log files are created in separate directories. The redo log files and control files are multiplexed. The database uses an undo tablespace, and has a default temporary tablespace. The following are tasks involved with creating and maintaining this database.
Parent topic: Scenarios for Using Oracle Managed Files
17.5.2 Scenario 2: Create and Manage a Database with Database and Fast Recovery Areas
An example illustrates creating and managing a database with both database and fast recovery areas.
In this scenario, a DBA creates a database where the control files and redo log files are multiplexed. Archived logs and RMAN backups are created in the Fast Recovery Area. The following tasks are involved in creating and maintaining this database:
Parent topic: Scenarios for Using Oracle Managed Files
17.5.3 Scenario 3: Adding Oracle Managed Files to an Existing Database
An example illustrates adding Oracle Managed Files to an existing database.
Assume in this case that an existing database does not have any Oracle Managed Files, but the DBA would like to create new tablespaces with Oracle Managed Files and locate them in directory /u03/oradata
.
Parent topic: Scenarios for Using Oracle Managed Files