You can restore an instance or table that was deleted or modified accidentally to the original cluster by using either of the following two methods: restore data to a previous point in time or restore data from a backup set (snapshot).

The difference between the two methods is whether or not the point in time that you want to restore data to is the time that a backup set was created. If the point in time that you want to restore data to is when a backup set was created, you can choose to restore data from a backup set (snapshot). If no backup sets were created at the point in time that you want to restore data to, you can only choose to restore data to a previous point in time.

Overall process

The restoration process is the same for all methods. You need to restore the data of the instance or table to the original cluster, and then compare the data in the original cluster.

Estimated time required for restoration

The time required for instance and table restoration depends on the sizes of the backup set and redo logs. The following table shows the estimated time required for data restoration.

Step Estimated time
Restore data from a backup set (snapshot) 3 GB/minute
Restore data by using redo logs
Note Redo logs are used only when you want to restore data to a previous point in time.
1.5 GB/minute

For example, if the sizes of a backup set (snapshot) and redo logs are 10 GB and 3 GB, you can use the following formulas to calculate the required restoration time:

  • Time required to restore the data of the backup set (snapshot): 10/3 = 3.3 minutes
  • Time required to restore data by using redo logs: 3/1.5 = 2 minutes

The total required time is estimated to be more than 5 minutes.

Note We recommend that you restore data during off-peak hours.