What is the purpose of Oracle Flashback Transaction?
Oracle Flashback Transaction Query is a useful tool to diagnose and repair changes made to the database at the transaction level. With it you can analyze transactions and recover from user or application errors.
How does Flashback work in Oracle?
Oracle Flashback Database enables point-in-time-recovery of the entire database without requiring a traditional restore and recovery operation. It rewinds the entire database to a specified point in time in the past by undoing all the changes that were made since that time.
Which two are prerequisites for performing a flashback transaction?
|Question ID 2248||Which two are prerequisites for performing a flashback transaction?|
|Option A||A. Flashback Database must be enabled.|
|Option B||B. Undo retention guarantee for the database must be configured.|
|Option C||C. EXECUTE privilege on the DBMS_FLASHBACK package must be granted to the user flashing back transaction.|
Which of the following privilege is required on the DBMS Flashback package to run that package?
You must have the EXECUTE privilege on the DBMS_FLASHBACK package. To use the DBMS_FLASHBACK package in your PL/SQL code: Call DBMS_FLASHBACK.
How do I know if flashback is enabled?
Use the following command to check if Flashback Database is enabled for your target database: SELECT FLASHBACK_ON FROM V$DATABASE; To enable Flashback Database: Ensure that you configure a fast recovery area and that the database is running in ARCHIVELOG mode.
Does Flashback database need archive logs?
Your database must be running in ARCHIVELOG mode, because archived logs are used in the Flashback Database operation. You must have a fast recovery area enabled, because flashback logs can only be stored in the fast recovery area.
Where are Oracle restore points located?
You can also use the following query to view only the guaranteed restore points: SQL> SELECT NAME, SCN, TIME, DATABASE_INCARNATION#, GUARANTEE_FLASHBACK_DATABASE, STORAGE_SIZE FROM V$RESTORE_POINT WHERE GUARANTEE_FLASHBACK_DATABASE=’YES’; For normal restore points, STORAGE_SIZE is zero.
How does Flashback calculate database progress?
The progress of Flashback Database during the restore phase can be monitored by querying the V$SESSION_LONGOPS view. The opname is Flashback Database . Under the column TOTALWORK is the number of megabytes of flashback logs that must be read.
Can we flashback truncate table?
By default they are disabled for all tables, but it can be activated, and will preserve your data even after a truncate. Moreover, even if you have the FDAs, you cannot just flashback the table, because TRUNCATE is a DDL operation, and will throw you an error that the table definition has been changed.
Does Flashback database generate redo?
The database restores the version of each block that is immediately prior to the target time. The database then uses redo logs to reapply changes that were made after these blocks were written to the flashback logs. Redo logs on disk or tape must be available for the entire time period spanned by the flashback logs.
How do I restore a flashback database?
To restore your database to a guaranteed restore point, follow the steps below:
- $> sqlplus / as sysdba;
- SQL> select current_scn from v$database;
- SQL> shutdown immediate;
- SQL> startup mount;
- SQL> select * from v$restore_point;
- SQL> flashback database to restore point CLEAN_DB;
- SQL> alter database open resetlogs;
Is there a Flashback Query in Oracle 10g?
Flashback Query (AS OF) in Oracle Database 10g. Flashback Query allows the contents of a table to be queried with reference to a specific point in time, using the AS OF clause. Essentially it is the same as the DBMS_FLASHBACK functionality or Oracle 9i, but in a more convenient form.
How to grant transaction privilege in Oracle Flashback?
Grant the SELECT ANY TRANSACTION privilege. To allow execution of undo SQL code retrieved by an Oracle Flashback Transaction Query, grant SELECT, UPDATE, DELETE, and INSERT privileges for specific tables. To allow access to the features in the DBMS_FLASHBACK package, grant the EXECUTE privilege on DBMS_FLASHBACK.
How to do a Flashback Transaction in SQL?
You can also obtain the SQL code to undo the changes to particular rows affected by a transaction. You typically use Flashback Transaction Query in conjunction with a Flashback Version Query that provides the transaction IDs for the rows of interest. To perform a Flashback Transaction Query, you select from the FLASHBACK_TRANSACTION_QUERYview.
How to recover drop tables in Oracle flash back?
To Recover Drop tables the RECYCLEBIN parameter must be turned ON, otherwise you will not be able to recover drop tables For Example, suppose a user accidently drops emp table Now for user it appears that table is dropped but it is actually renamed and placed in Recycle Bin.