**************FLASHBACK DATABASE *************
Requirments:
-------------
>> You must have a flash recovery area enabled, because flashback logs can only be stored in the flash recovery area.
>> For Real Application Clusters databases, the flash recovery area must be stored in a clustered file system or in ASM.
New:
-----
>> Now in 10gR2 flashback database can be done beyond the Open resetlogs.
Limitations of Flashback database:
------------------------------------
>> Flashback database cannot be used for media failure or accidential deletion of datafiles or shrink datafiles.
>> Cannot go beyond the restoration of the controlfile, because all the flashback log information is discarded.
>> Flashback database can cause problem for datafiles if there is any database objects which is in nologging mode.
>> Be careful when creating a tablespace and reverting back the database.The created tablespace may get dropped.
********************* Flashback Table ******************
>> You must have been granted the FLASHBACK ANY TABLE system privilege or you must have the FLASHBACK object privilege on the table.
>> Undo information retained in the undo tablespace must go far enough back in time to satisfy the specified target point in time or SCN for the FLASHBACK TABLE operation.
>> The database disables triggers on the affected table before performing a FLASHBACK TABLE operation, and after the operation returns them to the state they were in before the operation (enabled or disabled).
>> Constraints of the table will be checked. If the Operation violates any constraints, that it will be aborted.
>> Flashback database doesnt cause the Statistics of the table to be flashed back.
****************** Flashback Versions Query ****************
The lower and upper boundaries can either be specific timestamps/SCNs or the keywords MINVALUE and MAXVALUE. These keywords instruct Oracle to retrieve all available data versions. The age of the data available is determined by the undo_retention parameter.
Requirments:
-------------
>> You must have a flash recovery area enabled, because flashback logs can only be stored in the flash recovery area.
>> For Real Application Clusters databases, the flash recovery area must be stored in a clustered file system or in ASM.
New:
-----
>> Now in 10gR2 flashback database can be done beyond the Open resetlogs.
Limitations of Flashback database:
------------------------------------
>> Flashback database cannot be used for media failure or accidential deletion of datafiles or shrink datafiles.
>> Cannot go beyond the restoration of the controlfile, because all the flashback log information is discarded.
>> Flashback database can cause problem for datafiles if there is any database objects which is in nologging mode.
>> Be careful when creating a tablespace and reverting back the database.The created tablespace may get dropped.
********************* Flashback Table ******************
>> You must have been granted the FLASHBACK ANY TABLE system privilege or you must have the FLASHBACK object privilege on the table.
>> Undo information retained in the undo tablespace must go far enough back in time to satisfy the specified target point in time or SCN for the FLASHBACK TABLE operation.
>> The database disables triggers on the affected table before performing a FLASHBACK TABLE operation, and after the operation returns them to the state they were in before the operation (enabled or disabled).
>> Constraints of the table will be checked. If the Operation violates any constraints, that it will be aborted.
>> Flashback database doesnt cause the Statistics of the table to be flashed back.
****************** Flashback Versions Query ****************
The lower and upper boundaries can either be specific timestamps/SCNs or the keywords MINVALUE and MAXVALUE. These keywords instruct Oracle to retrieve all available data versions. The age of the data available is determined by the undo_retention parameter.
No comments:
Post a Comment