Oracle’s Flashback technology is a set of features that provide an easy way to recover data in case of logical corruptions, user error or other data loss issues. Its purpose is to allow the Oracle database to be reverted back to a previous state before the data loss occurred. Using Flashback, it is possible to recover dropped tables, deleted rows or even the entire database to a previous state, without performing a full database restore from a backup.
Oracle Flashback works by creating and maintaining a set of historical views and metadata that can be used to query the state data at different points in time. These views and metadata are updated automatically as the data changes and can be used in conjunction with the Oracle SQL language to perform queries against the historical state data.
One of the main benefits of Flashback technology is that it reduces the time required to recover data compared to more traditional backup and recovery methods. With Flashback technology, the recovery time objective (RTO) and recovery point objective (RPO) are significantly reduced, which is especially important for mission-critical systems that require high availability.
To use Flashback technology for data recovery, there are several features that can be utilized:
Flashback Query: This feature enables the retrieval of a specific set of data that was present in the past at a specific moment in time. It can be useful to retrieve accidentally deleted rows or to revert changes to data against a specific time. The query is performed using AS OF, which is included in the SELECT statement.
Flashback Table: This feature allows you to recover a table or its contents to a previous state. You can use this feature to recover a dropped table or to recover a specific version of a table by specifying the timestamp or SCN at which to recover the table.
Flashback Drop: This feature enables the recovery of a dropped table or any other object that has been dropped. It provides an easy way to recover data that has been dropped accidentally or mistakenly.
Flashback Transaction: This feature allows you to recover a transaction or a set of transactions to a previous state. You can use this feature to recover from logical corruptions or user errors that have caused data loss.
In summary, using Oracle Flashback technology, it is possible to quickly recover data from logical corruptions, user errors or other data loss issues. The various features of Flashback technology provide a quick and easy way to recover data, which reduces the time required for data recovery and ensures high availability of the Oracle database.