TIMEOUT integer 

Use the TIMEOUT clause to specify in minutes the wait period of the managed recovery operation. The recovery process waits for integer minutes for a requested archived log redo to be available for writing to the automated standby database. If the redo log file does not become available within that time, the recovery process terminates with an error message. You can then issue the statement again to return to automated standby recovery mode. 

If you do not specify this clause, the database remains in automated standby recovery mode until you reissue the statement with the RECOVER CANCEL clause or until instance shutdown or failure. 

CANCEL 

Use the CANCEL clause to terminate the managed recovery operation after applying all the redo in the current archived redo file. 

CANCEL IMMEDIATE 

Specify CANCEL IMMEDIATE to terminate the managed recovery operation after applying all the redo in the current archived redo file or after the next redo log file read, whichever comes first.

Restriction: This clause cannot be issued from the same session that issued the RECOVER MANAGED STANDBY DATABASE statement. 

NOPARALLEL 

Specify NOPARALLEL for serial execution. This is the default. 

PARALLEL 

Specify PARALLEL if you want Oracle to select a degree of parallelism equal to the number of CPUs available on all participating instances times the value of the PARALLEL_THREADS_PER_CPU initialization parameter. 

PARALLEL integer 

Specification of integer indicates the degree of parallelism, which is the number of parallel threads used in the parallel operation. Each parallel thread may use one or two parallel execution servers. Normally Oracle calculates the optimum degree of parallelism, so it is not necessary for you to specify integer. 

CREATE DATAFILE 

Use the CREATE DATAFILE clause to create a new empty datafile in place of an old one. You can use this clause to re-create a datafile that was lost with no backup. The 'filename' must identify a file that is or was once part of the database. The filespec specifies the name and size of the new datafile. If you omit the AS clause, Oracle creates the new file with the name and size as the file specified by 'filename'. 

During recovery, all archived redo logs written to since the original datafile was created must be applied to the new, empty version of the lost datafile. 

Oracle creates the new file in the same state as the old file when it was created. You must perform media recovery on the new file to return it to the state of the old file at the time it was lost.  

Restriction: You cannot create a new file based on the first datafile of the SYSTEM tablespace. 

DATAFILE 'filename' 

The DATAFILE clauses affect your database files as follows: 

ONLINE  

Specify ONLINE to bring the datafile online.  

OFFLINE  

Specify OFFLINE to take the datafile offline. If the database is open, you must perform media recovery on the datafile before bringing it back online, because a checkpoint is not performed on the datafile before it is taken offline. 

DROP takes a datafile offline when the database is in NOARCHIVELOG mode. 

RESIZE 

Specify RESIZE if you want Oracle to attempt to increase or decrease the size of the datafile to the specified absolute size in bytes. Use K or M to specify this size in kilobytes or megabytes. There is no default, so you must specify a size.

If sufficient disk space is not available for the increased size, or if the file contains data beyond the specified decreased size, Oracle returns an error. 

autoextend_clause 

Use the autoextend_clause to enable or disable the automatic extension of a datafile. If you do not specify this clause, datafiles are not automatically extended. 

OFF disables autoextend if it is turned on. NEXT and MAXSIZE are set to zero. Values for NEXT and MAXSIZE must be respecified in further ALTER DATABASE AUTOEXTEND statements. 

• ON enables autoextend.

• NEXT specifies in bytes the size of the next increment of disk space to be automatically allocated to the datafile when more extents are required. Use K or M to specify this size in kilobytes or megabytes. The default is one data block.

• MAXSIZE specifies the maximum disk space allowed for automatic extension of the datafile.

• UNLIMITED sets no limit on allocating disk space to the datafile.

END BACKUP  

Specify END BACKUP to avoid media recovery on database startup after an online tablespace backup was interrupted by a system failure or instance failure or SHUTDOWN ABORT. 

Caution: Do not use ALTER TABLESPACE ... END BACKUP if you have restored any of the files affected from a backup. Media recovery is fully described in Oracle8i Backup and Recovery Guide.

TEMPFILE 'filename' 

Lets you resize your temporary datafile or specify the autoextend_clause, with the same effect as with a permanent datafile.

Restriction: You cannot specify TEMPFILE unless the database is open. 

DROP 

Specify DROP to drop tempfile from the database. The tablespace remains. 

ARCHIVELOG 

Specify ARCHIVELOG if you want the contents of a redo log file group to be archived before the group can be reused. This mode prepares for the possibility of media recovery. Use this clause only after shutting down your instance normally or immediately with no errors and then restarting it, mounting the database in parallel server disabled mode.  

NOARCHIVELOG 

Specify NOARCHIVELOG if you do not want the contents of a redo log file group to be archived so that the group can be reused. This mode does not prepare for recovery after media failure.  

Use the ARCHIVELOG clause and NOARCHIVELOG clause only if your instance has the database mounted in Oracle Parallel Server disabled mode, but not open. 

ADD LOGFILE 

Use the ADD LOGFILE clause to add one or more redo log file groups to the specified thread, making them available to the instance assigned the thread.  

THREAD integer 

The THREAD clause is applicable only if you are using Oracle with the Parallel Server option in parallel mode. integer is the thread number. The number of threads you can create is limited by the value of the MAXINSTANCES parameter specified in the CREATE DATABASE statement.

If you omit THREAD, the redo log file group is added to the thread assigned to your instance.  

GROUP integer 

The GROUP clause uniquely identifies the redo log file group among all groups in all threads and can range from 1 to the MAXLOGFILES value. You cannot add multiple redo log file groups having the same GROUP value. If you omit this parameter, Oracle generates its value automatically. You can examine the GROUP value for a redo log file group through the dynamic performance view V$LOG.  

filespec 

Each filespec specifies a redo log file group containing one or more members, or copies.

See Also: the syntax description of filespec in filespec

ADD LOGFILE MEMBER 

Use the ADD LOGFILE MEMBER clause to add new members to existing redo log file groups. Each new member is specified by 'filename'. If the file already exists, it must be the same size as the other group members, and you must specify REUSE. If the file does not exist, Oracle creates a file of the correct size. You cannot add a member to a group if all of the group's members have been lost through media failure.  

You can specify an existing redo log file group in one of these ways:  

GROUP integer 

Specify the value of the GROUP parameter that identifies the redo log file group.  

filename[s] 

List all members of the redo log file group. You must fully specify each filename according to the conventions of your operating system.  

DROP LOGFILE  

Use the DROP LOGFILE clause to drop all members of a redo log file group. Specify a redo log file group as indicated for the ADD LOGFILE MEMBER clause.

• To drop the current log file group, you must first issue an ALTER SYSTEM SWITCH LOGFILE statement.

  See Also: ALTER SYSTEM

• You cannot drop a redo log file group if it needs archiving.

• You cannot drop a redo log file group if doing so would cause the redo thread to contain less than two redo log file groups.

DROP LOGFILE MEMBER  

Use the DROP LOGFILE MEMBER clause to drop one or more redo log file members. Each 'filename' must fully specify a member using the conventions for filenames on your operating system.

• To drop a log file in the current log, you must first issue an ALTER SYSTEM SWITCH LOGFILE statement.

  See Also: ALTER SYSTEM

• You cannot use this clause to drop all members of a redo log file group that contains valid data. To perform this operation, use the DROP LOGFILE clause.

CLEAR LOGFILE  

Use the CLEAR LOGFILE clause to reinitialize an online redo log, optionally without archiving the redo log. CLEAR LOGFILE is similar to adding and dropping a redo log, except that the statement may be issued even if there are only two logs for the thread and also may be issued for the current redo log of a closed thread. 

UNARCHIVED  

You must specify UNARCHIVED if you want to reuse a redo log that was not archived. 

Caution: Specifying UNARCHIVED makes backups unusable if the redo log is needed for recovery.

UNRECOVERABLE DATAFILE 

You must specify UNRECOVERABLE DATAFILE if you have taken the datafile offline with the database in ARCHIVELOG mode (that is, you specified ALTER DATABSE ... DATAFILE OFFLINE without the DROP keyword), and if the unarchived log to be cleared is needed to recover the datafile before bringing it back online. In this case, you must drop the datafile and the entire tablespace once the CLEAR LOGFILE statement completes. 

Do not use CLEAR LOGFILE to clear a log needed for media recovery. If it is necessary to clear a log containing redo after the database checkpoint, you must first perform incomplete media recovery. The current redo log of an open thread can be cleared. The current log of a closed thread can be cleared by switching logs in the closed thread. 

If the CLEAR LOGFILE statement is interrupted by a system or instance failure, then the database may hang. If this occurs, reissue the statement after the database is restarted. If the failure occurred because of I/O errors accessing one member of a log group, then that member can be dropped and other members added. 

CREATE STANDBY CONTROLFILE 

Use the CREATE STANDBY CONTROLFILE clause to create a control file to be used to maintain a standby database. If the file already exists, you must specify REUSE.

See Also: Oracle8i Standby Database Concepts and Administration.

BACKUP CONTROLFILE 

Use the BACKUP CONTROLFILE clause to back up the current control file. 

TO 'filename' 

Specify the file to which the control file is backed up. You must fully specify the filename using the conventions for your operating system. If the specified file already exists, you must specify REUSE.  

TO TRACE 

Specify TO TRACE if you want Oracle to write SQL statements to the database's trace file rather than making a physical backup of the control file. The SQL statements can start up the database, re-create the control file, and recover and open the database appropriately, based on the created control file. 

You can copy the statements from the trace file into a script file, edit the statements as necessary, and use the database if all copies of the control file are lost (or to change the size of the control file). 

• RESETLOGS indicates that the SQL statement written to the trace file for starting the database is ALTER DATABASE OPEN RESETLOGS.

• NORESETLOGS indicates that the SQL statement written to the trace file for starting the database is ALTER DATABASE OPEN NORESETLOGS.

STANDBY DATABASE 

Specify STANDBY to mount the standby database.

See Also: Oracle8i Standby Database Concepts and Administration

CLONE DATABASE 

Specify CLONE to mount the clone database.

See Also: Oracle8i Backup and Recovery Guide

READ ONLY

Specify READ ONLY to restrict users to read-only transactions, preventing them from generating redo logs. You can use this clause to make a standby database available for queries even while archive logs are being copied from the primary database site. 

Restrictions:

• You cannot open a database READ ONLY if it is currently opened READ WRITE by another instance.

• You cannot open a database READ ONLY if it requires recovery.

• You cannot take tablespaces offline while the database is open READ ONLY. However, you can take datafiles offline and online, and you can recover offline datafiles and tablespaces while the database is open READ ONLY.

READ WRITE

Specify READ WRITE to open the database in read-write mode, allowing users to generate redo logs. This is the default. 

RESETLOGS 

Specify RESETLOGS to reset the current log sequence number to 1 and discards any redo information that was not applied during recovery, ensuring that it will never be applied. This effectively discards all changes that are in the redo log, but not in the database.

You must specify RESETLOGS to open the database after performing media recovery with an incomplete recovery using the RECOVER clause or with a backup control file. After opening the database with this clause, you should perform a complete database backup.  

NORESETLOGS 

Specify NORESETLOGS to retain the current stat of the log sequence number and redo log files. 

Restriction: You can specify RESETLOGS and NORESETLOGS only after performing incomplete media recovery or complete media recovery with a backup control file. In any other case, Oracle uses the NORESETLOGS automatically.  

PUBLIC 

Specify PUBLIC to make the enabled thread available to any instance that does not explicitly request a specific thread with the initialization parameter THREAD. If you omit PUBLIC, the thread is available only to the instance that explicitly requests it with the initialization parameter THREAD.