LOGGING versus NOLOGGING

Despite the importance of the redo entries, Oracle gives users the ability to limit redo generation on tables, partitions, tablespaces, and indexes by setting them in the NOLOGGING mode. NOLOGGING affects the recoverability of a database and before going into how to limit the redo generation, it is important to clear the misunderstanding that NOLOGGING is the way out of redo generation. The following are some interesting points regarding this topic:

• NOLOGGING is designed to handle bulk inserts of data which can be easily reproduced. (Remember that the UPDATE and DELETE operations will always be logged.)

• Regardless of the LOGGING status, writing to the UNDO blocks will always cause generation of redo.

• LOGGING should not be disabled on a primary database if it has one or more standby databases. For this reason, Oracle introduced the ALTER DATABASE FORCE LOGGING command to place the database in the FORCE LOGGING mode—meaning that the NOLOGGING attribute will not have any...