Therefore, some SCNs after that point can refer either to changes that were abandoned or changes in the current history of the database. Specify the name of the restore point. 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. Restore and recover the database, performing the following actions in the RUN command: Set the end time for recovery to the time just before the loss of the data. Because the original name in FLASHBACK TABLE refers to the most recently dropped table with this name, the last table dropped is the first retrieved. If the database is mounted, then it must have been shut down consistently before being mounted unless it is a physical standby database. Instead, the table is renamed and, along with any associated objects, placed in 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. If you are satisfied with the results, then perform either of the following mutually exclusive actions: Make the database available for updates by opening the database with the RESETLOGS option. 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. This includes restoring the PDB, making its file online, and then performing a complete recovery of the PDB. The most powerful PL/SQL Excel API in the World. Therefore, it is faster than flashing back a PDB using shared undo to an SCN or other type of restore point. If the fast recovery area does not have the required space, use an alternate location by specifying the AUXILIARY DESTINATION clause. The following example creates a normal restore point, updates a table, and then flashes back the altered table to the restore point. You can reverse the effects of a DROP TABLE statement.
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. You must use the recycle bin name of the object in your query rather than the object's original name. This section explains the most common scenario for using Flashback Database to reverse unwanted changes to your database. Objects must meet the following prerequisites to be eligible for retrieval from the recycle bin: The recycle bin is only available for non-system, locally managed tablespaces. 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. operation. Oracle Database Concepts and Oracle Database Administrator's Guide for more information about undo data and automatic undo management, Oracle Database Development Guide to learn how to use the logical flashback features, "Overview of Flashback Database, Restore Points and Guaranteed Restore Points" for more information about setting up your database to use Flashback Database, and on the related restore points feature. When you specify a restore point name in a PDB or for a PDB operation, the name is first interpreted as a PDB restore point for the concerned PDB. In the latter case, you must explicitly execute the RESET DATABASE to reset the database to the incarnation that was current at the target SCN. Some dependent objects such as indexes may possibly have been reclaimed because of space pressure. To create a guaranteed PDB restore point, the current container must be the root and you must have the SYSDBA, SYSBACKUP, or SYSDG system privilege, granted commonly, or the current container must be the PDB for which you want to create the restore point and you must have the SYSDBA, SYSBACKUP, or SYSDG system privilege, granted commonly or granted locally in that PDB.
Use the SET command with the DECRYPTION WALLET OPEN IDENTIFIED BY option to specify the password that must be used to open the password-based keystore. Restore and recover the PDB pdb2. To return the database to a guaranteed restore point, you must have previously defined a guaranteed restore point as described in "Using Normal and Guaranteed Restore Points". This clause enables you to create a PDB restore point when you are connected to the root. Open your database for read/write, abandoning all changes after the target SCN. If the database is currently open read-only, then execute the following commands in SQL*Plus: Use Oracle Data Pump Export to make a logical backup of the objects whose state was corrupted. Note that this command is not required when an auto-login software keystore is used. In some respects, flashback logging is like a continuous backup. As explained in "Database Incarnations", an incarnation is in this path if it was not abandoned after the database was previously opened with the RESETLOGS option. Use the RECOVER DATABASE UNTIL command to perform DBPITR, bringing the database to the target time of 7:55 a.m. on October 8, just before the data was lost. 2022. But I receive an error: This looks very strange. You must have created a fast recovery area before creating a guaranteed restore point. Flashing back a PDB using shared undo to a clean PDB restore point does not require restoring backups or creating a clone instance. The following example queries the RECYCLEBIN view to determine the original names of dropped objects: If you plan to manually restore original names for dependent objects, then ensure that you make note of each dependent object's system-generated recycle bin name before you restore the table.
The procedure makes the following assumptions: You are performing DBPITR within the current database incarnation. Take all the files corresponding to pdb2 offline using the following command: Shut down the CDB and bring it to a mounted state as follows: Rewind the CDB to the desired point in time. Media recovery with backups are the last option when flashback technologies cannot be used to undo the most recent changes. If you have created restore points, then you can list available restore points by executing the following query: Ensure that enough undo data exists to rewind the table to the specified target. When you drop a table, the table and all of its dependent objects go into the recycle bin together. Unlike the other flashback features, it operates at a physical level and reverts the current data files to their contents at a past time. 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. 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. The database automatically manages such restore points. After this phase completes, Flashback Database then uses redo logs to reapply changes that were made after these blocks were written to the flashback logs. Guaranteed restore points can use considerable space in the fast recovery area. A restore point is always associated with the current incarnation when it was created. Depending on system activity, a dropped object may remain in the recycle bin for seconds or for months. Your entire database is unavailable during the DBPITR.
In this example, the target time is the time when the SCN was 128048. The progress of Flashback Database during the recovery phase can be monitored by querying the view V$RECOVERY_PROGRESS. For example, run the following query to list the logs in the current database incarnation (sample output included): For example, if you discover that a user accidentally dropped a tablespace at 9:02 a.m., then you can recover to 9 a.m., just before the drop occurred. Its important to note that the GRP is not active in the same but in another PDB. Determine the target time to which the CDB must be recovered. Restore the control file from the October 2 backup and mount it. You can perform a flashback of the whole CDB to a point in time when the SCN is greater than 128756. If you are satisfied with the state of the database, then end the procedure with Step 8. When you set the GRP in the CDB$ROOT and then drop the tablespace from a PDB, the FLASHBACK operation will succeed. This ensures that the data files restored from backup have time stamps early enough to be used in the subsequent RECOVER operation. To perform a flashback of temp_employees: Connect SQL*Plus to the target database and identify the current SCN. Once I set this, I can drop my tablespace now: Actually this behavior is independent from Oracle Multitenant. If unwanted database changes are limited to specific tables or table partitions, then you can use a previously created RMAN backup to return only these objects to a point in time before the unwanted changes occurred. This restriction exists because if rowids before the flashback were stored by the application, then there is no guarantee that the rowids correspond to the same rows after the flashback. Upgrade your Database NOW! That is, any user who can drop an object can perform Flashback Drop to retrieve the dropped object from the recycle bin. The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network. 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. Alternatively, you can use a SQL query to determine the log sequence number that contains the target SCN and then recover through this log. A restore point can be used to flash back a table or the database to the time specified by the restore point without the need to determine the SCN or timestamp. The database automatically creates, deletes, and resizes flashback logs in the recovery area. Any users who had the READ or SELECT privilege over an object before it was dropped continue to have the READ or SELECT privilege over the object in the recycle bin. Vienna Calling Austrian Oracle User Group Conference 2018, RMAN backup generates traces in Oracle 12.2.0.1. You can specify CLEAN only when creating a PDB restore point. You can specify either the name of the table in the recycle bin or the original table name. For example, assume that at 17:00 an HR administrator discovers that an employee is missing from the hr.temp_employees table. To perform a Flashback Database operation: Connect SQL*Plus to the target database and determine the desired SCN, restore point, or point in time for the FLASHBACK DATABASE command. SQL Statements: CREATE LIBRARY to CREATE SCHEMA, Oracle Database Backup and Recovery User's Guide, creating and using restore points and guaranteed restore points, Description of the illustration create_restore_point.eps. The undo data in the undo tablespace must extend far enough back in time to satisfy the flashback target time or SCN. If the database control file is restored from backup or re-created, then all accumulated flashback log information is discarded. Use the FLASHBACK TABLE TO BEFORE DROP statement. You can use RMAN to create restore points in the process of implementing an archival backup. The flashback operation uses undo to re-create the original data. Consequently, you cannot enable Flashback Database after a failure is discovered and then use Flashback Database to rewind through this failure. Open the database read-only in SQL*Plus and run some queries to verify the database contents. Example 18-2 shows the retrieval from the recycle bin of all three dropped temp_employees tables from the previous example, with each assigned a new name.
The process of performing recovery is similar to that of DBPITR. The point to which you can perform Flashback Table is determined by the undo retention period, which is the minimal time for which undo data is kept before being recycled, and tablespace characteristics. You can use the Flashback Query features to help you identify when the logical corruption occurred. To perform a flashback of a CDB to a point that is beyond the point in time to which a DBPITR operation was performed on the PDB: Start RMAN and connect to the root as a user with the SYSBACKUP or SYSDBA privilege. Restore the data files and recover the database. However, an explicit RESET DATABASE TO INCARNATION command is required when you use FLASHBACK DATABASE to rewind the database to an SCN in an abandoned database incarnation. If the backups were encrypted using transparent encryption, and if a password-based software keystore was used, then the keystore password must be provided before the restore operation is performed. You can query objects in the recycle bin, just as you can query other objects. You can then recover the database to the current point in time and reimport the exported objects, thus returning these objects to their state before the unwanted change without abandoning all other changes. The following commands restore and recover pdb2 and then open this PDB: When you use Flashback Database to rewind a database to a past target time, Flashback Database determines which blocks changed after the target time and restores them from the flashback logs. You must have been granted the SYSDBA privilege and be using a multitenant database. 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. Therefore, Oracle recommends that you create guaranteed restore points only after careful consideration. For a complete account of command prerequisites and usage notes, refer to the RECOVER entry in Oracle Database Backup and Recovery Reference. Therefore, it is advisable to record the current SCN. RMAN TSPITR is an advanced technique described in Chapter 21, "Performing RMAN Tablespace Point-in-Time Recovery (TSPITR)". Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you. To return the database to the point in time immediately before the most recent OPEN RESETLOGS operation, see "Rewinding an OPEN RESETLOGS Operation with Flashback Database". In this scenario, assume that you want to perform a flashback of the hr.temp_employees table after a user made some incorrect updates. For example, execute the following query: Determine the target incarnation number for the Flashback Database operation, that is, the incarnation key for the parent incarnation. Flashback logs are written sequentially and often in bulk. Mike Dietrich's Blog About Oracle Database Upgrades Mostly. This scenario assumes that you are rewinding the database to a point in time within the current database incarnation. But when you check the alert.log and V$DATAFILE youll see that the file status is OFFLINE. When performing DBPITR, you can avoid errors by using the SET UNTIL command to set the target time at the beginning of the procedure, rather than specifying the UNTIL clause on the RESTORE and RECOVER commands individually. A flashback operation retrieves the table from the recycle bin. Oracle Database retrieves all indexes defined on the table except for bitmap join indexes, and all triggers and constraints defined on the table except for referential integrity constraints that reference other tables. DBPITR works at the physical level to return the data files to their state at a target time in the past. Example 18-1 Dropping Multiple Objects with the Same Name. Take all files that correspond to the PDB for which PITR was performed offline. The steps to perform point-in-time recovery of PDBs are similar to the ones for performing DBPITR, with the differences described in this section. The progress of Flashback Database during the restore phase can be monitored by querying the V$SESSION_LONGOPS view. RMAN simplifies DBPITR in comparison to the user-managed DBPITR described in "Performing Incomplete Database Recovery". Restore points are also useful in various RMAN operations, including backups and database duplication. The database can be open, or mounted but not open. If dependencies exist, then decide whether to flash back these tables as well. You can use them to investigate past states of the database. When point-in-time recovery is performed on a PDB, you cannot directly rewind the CDB to a point that is earlier than the point at which DBPITR for the PDB was performed. set, I can now flashback to my initially created restore point: But be aware: You need only be aware of flashback logs for monitoring performance and determining disk space allocation for the recovery area. The following example recovers a PDB named PDB5 up to SCN 1066, and then opens it for read/write access. But in a Multitenant environment youll have now a different situation. The following example restores the BIN$gk3lsj/3akk5hg3j2lkl5j3d==$0 table, changes its name back to hr.employee_demo, and purges its entry from the recycle bin: The table name is enclosed in quotation marks because of the possibility of special characters appearing in the recycle bin object names. The reason is that dropping a tablespace wont be reversed by a FLASHBACK DATABASE operation. Flashback Database works by undoing changes to the data files that exist at the moment that you run the command.