Chapter 2. NOLOGGING Operations
You could be asking yourself why I want to talk about NOLOGGING operations in a backup and recovery book. The answer is simple: NOLOGGING operations will affect the recoverability of a database and due to this, it is very important for a DBA to understand this concept. It is the most visited topic on my blog www.oraclenz.org.
Many DBAs and developers use NOLOGGING operations when doing bulk inserts and massive deletion of data to reduce redo generation but many do not know that these statements will always generate redo, in other words, UPDATE or DELETE will always be logged. Later in this chapter, we will see some techniques that will reduce redo generation for massive updates and deletes.
In this chapter, we will cover the following topics:
LOGGING versus NOLOGGING
Disabling redo generation
NOLOGGING operations
How to reduce redo generation
Redo log wait events
Practice with some interesting scripts
NOLOGGING operations do not generate redo records in the redo log...
