Set and cancel flashback recovery area

In Oracle 10 Gb, the flash back family is divided into the following members: flashback database, flashback drop, flashback query (divided into flashback
Query, flashback version query, and flashback transaction query) and flashback table.

Flash recovery area contains: control file, archive file, flashback logs, control file, automatic backup control file, data file, data file copy, RMAN file (including Backup set, image backup ).

Backup recovery area backs up all content in the Flash recovery area.
1. Set the flash recovery zone
The Flash recovery zone is mainly set and managed through three initialization parameters:
Db_recovery_file_dest: Specifies the position of the flash recovery zone.
Db_recovery_file_dest_size: Specifies the available space size of the flash recovery zone.
Db_flashback_retention_target: specifies the time when the database can be rolled back. The unit is minute. The default value is 1440 minutes, that is, one day. Of course, in fact, the rollback time is still
It depends on the size of the flash recovery zone, because the flash log required for rollback is saved. Therefore, this parameter must be modified with db_recovery_file_dest_size.

SQL> ALTER SYSTEM SET db_recovery_file_dest_size=3g SCOPE=BOTH;System altered.SQL> ALTER SYSTEM SET db_recovery_file_dest=‘ D:/app/Administrator/flash_recovery_area ‘ SCOPE=BOTH;System altered.SQL> show parameter db_recovery_file_dest;NAME TYPE VALUE------------------------------------ ----------- ------------------------------db_recovery_file_dest string D:\app\Administrator\flash_rec overy_area db_recovery_file_dest_size big integer 3912MSQL> show parameter db_flashback;NAME TYPE VALUE------------------------------------ ----------- ------------------------------db_flashback_retention_target integer 1440SQL> show parameter db_recovery_file_dest;NAME TYPE VALUE------------------------------------ ----------- ------------------------------db_recovery_file_dest string D:\app\Administrator\flash_recovery_area

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2. Cancel the flash recovery zone
Set db_recovery_file_dest to null to disable the flash recovery zone. If flashback database is enabled, you cannot cancel flashing back to the recovery zone.

SQL> select flashback_on from V $ database; FLASHBACK_ON------------------YESSQL> alter system set db_recovery_file_dest = ''; Alter system set db_recovery_file_dest ='' * row 1st error: ORA-02097: Unable to modify parameters, because the specified value is invalid ORA-38775: cannot disable recovery zone-Flashback database enabled SQL> shutdown immediate; database disabled. The database has been detached. The Oracle routine has been disabled. SQL> startup Mount; the Oracle routine has been started. Total system global area 855982080 bytesfixed size 2180544 bytesvariable size 587205184 bytesdatabase buffers 260046848 bytesredo buffers 6549504 bytes database loaded. SQL> alter database flashback off; the database has been changed. SQL> alter database open; the database has been changed. SQL> select flashback_on from V $ database; FLASHBACK_ON------------------NOSQL> alter system set db_recovery_file_dest = ''; the system has changed. SQL> show parameter db_recovery_file_dest; Name type value ------------- -------------------------------- db_recovery_file_dest stringdb_recovery_file_dest_size big integer 3912 m
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From: http://blog.csdn.net/tianlesoftware/article/details/4677.pdf

Set and cancel flashback recovery area