flashback table in oracle 19c


The following query returns the current SCN: You can query available guaranteed restore points as follows (sample output included): If the flashback window does not extend far enough back into the past to reach the desired target time, and if you do not have a guaranteed restore point at the desired time, then you can achieve similar results by using database point-in-time recovery, as described in "Performing Database Point-in-Time Recovery". one or more tables back to a previous point in time without The retrieved indexes, triggers, and constraints have recycle bin names. 12c 19c oracle fixup If the PDB was configured with isolated mode setting, then open The effect of Flashback Database or DBPITR followed by an OPEN RESETLOGS operation is to return the database to a previous SCN, and to abandon changes after this point. Notice that the REGION_NAME for all the rows

affecting other database objects. The use of Flashback Database means that you do not require the use of storage snapshots. You can use the SQL*Plus command SHOW RECYCLEBIN as follows: The ORIGINAL NAME column shows the original name of the object, whereas the RECYCLEBIN NAME column shows the name of the object as it exists in the bin. You must also restore a control file from the database incarnation containing the target SCN.

You can query the V$PDB_INCARNATION view for the incarnation number. If the SCN to which you are rewinding is in the direct ancestral path, or if you are rewinding the database to a restore point, then an explicit RESET DATABASE command is not necessary for Flashback Database.

You can retrieve objects from the recycle bin with the FLASHBACK TABLE TO BEFORE DROP statement. Oracle Database does not revert statistics associated with table to their earlier form. The flashback features of the Oracle Database are more efficient than media recovery in most circumstances in which they are available. For such PDBs, you must perform one of the following mutually exclusive actions: Recover the entire CDB or perform a flashback operation for the entire CDB to a different SCN, Recover all the affected PDBs or perform a flashback database operation for all the affected PDBs to a different SCN, Basic Concepts of Database Point-in-Time Recovery. Determine the desired SCN, restore point, or point in time for the Flashback Database command. To ensure that the undo information is retained for Flashback Table operations, Oracle suggests setting the UNDO_RETENTION parameter to 86400 seconds (24 hours) or greater for the undo tablespace. To resolve this error and perform a flashback operation on a CDB across PDB PITR or PDB flashback, use the steps described in Performing Flashback Database Operations on a CDB When a PDB Was Recovered Using DBPITR in the Oracle Database Backup and Recovery Users Guide 12c Release 1 (12.1). If the resetlogs SCN is still within the flashback window, then proceed to the next step. Identify the time, SCN, or restore point to which you want to return the table. To enable currently disabled triggers selectively, use the ALTER TABLE enable_disable_clause before you issue the FLASHBACK TABLE statement with the ENABLE TRIGGERS clause.

The opname is Flashback Database. Therefore, the materialized view logs cannot be flashed back along with the table. Row movement must be enabled on a table before The base (read-only) data files in a sparse database are not encrypted. Many times you have been asked to drop tables in the test databases, but in this case you accidentally connect to the production database instead and drop hr.employee_demo. Afterward, use RMAN to recover the database to the present time: The following command, when connected to the root, opens all the PDBs: If you want to open only some PDBs, then you can open each PDB separately. Use Flashback Query or the alert log to determine when the logicla corruption occurred.

A restore point is always associated with the current incarnation when it was created. Flashback Table restores tables while automatically maintaining associated attributes such as current indexes, triggers, and constraints, and not requiring you to find and restore application-specific properties.

To flash back a table to a restore point, you must have the SELECT ANY DICTIONARY or FLASHBACK ANY TABLE system privilege or the SELECT_CATALOG_ROLE role. Determine the time, SCN, or log sequence to which the PDB must be To restore a control file from a noncurrent incarnation, you must execute LIST INCARNATION to identify the target database incarnation and specify this incarnation in the RESET DATABASE TO INCARNATION command. Therefore, some SCNs after that point can refer either to changes that were abandoned or changes in the current history of the database. Otherwise, use the CONFIGURE command to configure automatic channels, or include ALLOCATE CHANNEL commands within a RUN block. If you are satisfied with the state of the database, then end the procedure with Step 9. When a CDB uses local undo, performing a flashback database operation on a pluggable database (PDB) is straight-forward because only data files related to that PDB need to be modified.

You can also retrieve any table from the recycle bin, regardless of any collisions among original names, by using the unique recycle bin name of the table. Users must have the READ or SELECT and FLASHBACK privileges over an object in the recycle bin to query the object in the recycle bin. In this example, specify the incarnation current at the time of the backup of 2 October. If you do not use a fast recovery area, then you must specify the temporary location of the auxiliary set files by using the AUXILIARY DESTINATION clause. PITR of PDBs can only be performed using RMAN. Depending on the changes to your database, Flashback Technology can often reverse the unwanted changes more quickly and with less impact on database availability. The progress of Flashback Database during the recovery phase can be monitored by querying the view V$RECOVERY_PROGRESS. The following Data Definition Language (DDL) operations change the structure of a table: upgrading, moving, or truncating a table; adding a constraint to a table, adding a table to a cluster; modifying or dropping a column; adding, dropping, merging, splitting, coalescing, or truncating a partition or subpartition (except adding a range partition). After you perform one of these steps on the primary database, any standby database of this primary database can also skip the corrupted redo provided you perform the steps required to enable a standby to follow a primary after a PITR or Flashback on the PDB. The general information regarding PITR that is contained in this chapter applies to CDBs with the differences described in this section and its subsections. The following example performs point-in-time recovery for a sparse database till the SCN 2775080: This section describes variations of the basic Flashback Database and DBPITR scenarios. For example: The following query determines the names of the indexes of the retrieved hr.employee_demo table: The following statement renames the index to its original name of i_emp_demo: This step must be performed manually because the recycle bin does not preserve referential constraints on a table. In this case, you restore a whole database backup and then apply redo logs or incremental backups to re-create all changes up to a point in time before the unwanted change. If any unrecoverable operations are encountered during the small amount of redo apply required, then logically corrupt data blocks will result. Use the following steps: You cannot roll back a FLASHBACK TABLE statement, but you can issue another FLASHBACK TABLE statement and specify a time just before the current time. For example, run the following query to list the logs in the current database incarnation (sample output included): For example, if you discover that a user accidentally dropped a tablespace at 9:02 a.m., then you can recover to 9 a.m., just before the drop occurred. If you run FLASHBACK DATABASE when your target SCN is outside the flashback window, then FLASHBACK DATABASE fails with an ORA-38729 error. This employee was included in the table at 14:00, the last time the report was run. You can temporarily activate a physical standby database, use it for testing or reporting purposes, and then use Flashback Database to return it to its role as a physical standby. After the FLASHBACK TABLE statement issued above, this list should match the list in the first benchmark. If a table is in a non-system, locally managed tablespace, but one or more of its dependent segments (objects) is in a dictionary-managed tablespace, then these objects are protected by the recycle bin. To flash back a table to a restore point, you must have the SELECT ANY DICTIONARY or FLASHBACK ANY TABLE system privilege or the SELECT_CATALOG_ROLE role. Multiple flashback operations can be performed on a single PDB. Depending on system activity, a dropped object may remain in the recycle bin for seconds or for months. A complete database recovery after a media failure cannot succeed because you do not have all of the needed redo logs or incremental backups.

mypdb that was previously dropped. password-protected software keystore was used, then the keystore password must Allocate any channels required that are not configured. Shut down the database consistently, ensure that it is not opened by any instance, and then mount it: Repeat the query in Step 2 of this procedure. To flash back a table to before a DROP TABLE operation, you need only the privileges necessary to drop the table. When connected to the root, the following ALTER PLUGGABLE DATABASE command closes the PDB my_pdb. By default, the database disables triggers on the affected table before performing a FLASHBACK TABLE operation. Create table employees_test, with row movement enabled, from table employees of the sample hr schema: As a benchmark, list those salaries less than 2500: To allow time for the SCN to propagate to the mapping table used by the FLASHBACK TABLE statement, wait a minimum of 5 minutes prior to issuing the following statement. RMAN provides methods to manage redo corruption to data blocks in a PDB.

Likewise, when you perform Flashback Drop, the objects are generally all retrieved together. When you drop a table, the table and all of its dependent objects go into the recycle bin together. Use the FLASHBACK TABLE TO BEFORE DROP statement. The following example performs DBPITR on the PDB my_pdb until SCN 1000: The following example opens the PDB named my_pdb. This feature enables you to table. If V$DATABASE.RESETLOGS_CHANGE# is greater than V$FLASHBACK_DATABASE_LOG.OLDEST_FLASHBACK_SCN, then you can use Flashback Database to reverse the OPEN RESETLOGS operation. You are not trying to use FLASHBACK DATABASE to return to a point in time before the restore or re-creation of a control file. Restore the data files and recover the database. Rewinding an OPEN RESETLOGS Operation with Flashback Database, Rewinding the Database to an SCN in an Abandoned Incarnation Branch, Recovering the Database to an Ancestor Incarnation.

Specify the schema containing the table. Use the FLASHBACK TABLE statement to restore an earlier state of a table in the event of human or application error. The other PDBs and the CDB can remain open. "Rewinding an OPEN RESETLOGS Operation with Flashback Database" to return the database to the point in time immediately before the most recent OPEN RESETLOGS operation, "Rewinding the Database to an SCN in an Abandoned Incarnation Branch" to retrieve changes in abandoned incarnations. If you accidentally drop the pm.print_media table and want to retrieve it, then issue the following statement: If another print_media table has been created in the pm schema, then use the RENAME TO clause to rename the retrieved table: If you know that the employees table has been dropped multiple times, and you want to retrieve the oldest version, then query the USER_RECYLEBIN table to determine the system-generated name, and then use that name in the FLASHBACK TABLE statement. In some respects, flashback logging is like a continuous backup. If the backups were created using password-mode encryption, then you must provide the password used to decrypt backups before you run the RESTORE and RECOVER commands. A database upgrade fails or an upgrade script goes awry. The technique used by RMAN to perform flashback database operations depends on the type of undo configuration for the CDB. In this case, the database reverts to its role (primary or standby) at the target time for the Flashback Database operation. Instead, the table is renamed and, along with any associated objects, placed in the recycle bin. You must have the following privileges to use the Flashback Table feature: You must have been granted the FLASHBACK ANY TABLE system privilege or you must have the FLASHBACK object privilege on the table. If the command completes successfully, then the database is left mounted and recovered to the most recent SCN before the OPEN RESETLOGS operation in the previous incarnation. Other PDBs can remain open and operational while performing Flashback Database on a particular PDB. that the time format environment variables are appropriate before invoking The Flashback Table operation is executed in a single transaction, regardless of the number of tables specified in the Flashback list. Basic Concepts of Performing Flashback Database for CDBs and PDBs. Start RMAN and connect to a target database and recovery catalog, if required, as described in. If applicable, connect to a recovery catalog. The flashback operation uses undo to re-create the original data. If you must restore a backup server parameter file, then see "Restoring the Server Parameter File". You can recover to an SCN, time, log sequence number, or restore point. be provided before the restore operation is performed. The result is like the result of a DBPITR, including the OPEN RESETLOGS, but Flashback Database is typically faster because it does not require you to restore data files and requires only limited application of redo compared to media recovery.

Determine the time, SCN, restore point, or log sequence that ends recovery. However, you can only perform a flashback operation on a PDB to one of its ancestor incarnations. RMAN DBPITR restores the database from backups before the target time for recovery, then uses incremental backups and redo to roll the database forward to the target time. To return the database to a guaranteed restore point, you must have previously defined a guaranteed restore point. You need only be aware of flashback logs for monitoring performance and determining disk space allocation for the recovery area. After reopening the database read/write, you can import the exported objects with the Data Pump Import utility. The database also retrieves all triggers and constraints defined on the table except for referential integrity constraints that reference other tables. Oracle recommends that you create restore points at important times to make point-in-time recovery more manageable if it ever becomes necessary. Performing Point-in-Time Recovery of CDBs and PDBs.

19c 12c By default, Oracle Database disables all enabled triggers defined on table during the Flashback Table operation and then reenables them after the Flashback Table operation is complete. The examples below create a new table, employees_test, with row movement enabled, update values within the new table, and issue the FLASHBACK TABLE statement. A flashback operation retrieves the table from the recycle bin. Retrieving Objects Using Flashback Drop When Multiple Objects Share the Same Original Name. Perform a Flashback Database operation for the specified PDB to the desired point in time.

Certain prerequisites must be met to perform database point-in-time recovery (DBPITR). During normal operation, the database periodically writes old images of data file blocks to the flashback logs. You can recover a table or set of tables to a specified earlier point in time without taking any part of the database offline. Ensure that the backups required to recover the PDB are available. This process may involve restoring backups for a relatively small amount of data. When you perform a Flashback Database operation, the database uses flashback logs to access past versions of data blocks and also uses some data in the archived redo logs. ), Oracle Database Backup and Recovery User's Guide, Description of the illustration flashback_table.eps. When you drop a table, the database does not immediately remove the space associated with the table. You need a backup If a user with the SYSBACKUP privilege is performing the Your entire database is unavailable during the DBPITR. Oracle Flashback Database is the most efficient alternative to DBPITR. Use the value from the Inc Key column to identify the incarnation. is updated to ORACLE. Nevertheless, you can use the technique in "Rewinding the Database to an SCN in an Abandoned Incarnation Branch" to return the database to that range of SCNs while they remain in the flashback window. Also, RMAN may need to restore redo logs and incremental backups to recover the data files. For a PDB that uses shared undo, you can optionally include the AUXILIARY DESTINATION clause to specify a location for the auxiliary instance that stores data files restored as part of the Flashback Database operation. Your database is using the current server parameter file. Use the RESTORE and RECOVER commands to perform point-in-time recovery for a whole CDB. Use Oracle Data Pump Export to make a logical backup of the objects whose state was corrupted. Tables that have fine-grained auditing (FGA) and Virtual Private Database (VPD) policies defined over them are not protected by the recycle bin.