CHAPTER 9Redo and Undo
This chapter describes two of the most important pieces of data in an Oracle database: redo and undo. Redo is the information Oracle records in online (and archived) redo log files in order to "replay" your transaction in the event of a failure. Undo is the information Oracle records in the undo segments in order to reverse, or roll back, your transaction.
In this chapter, we will discuss topics such as how redo and undo (rollback) are generated, and how they fit into transactions, recovery, and so on. We'll start off with a high-level overview of what undo and redo are and how they work together. We'll then drill down into each topic, covering each in more depth and discussing what you, the developer, need to know about ...
Get Expert Oracle Database Architecture: 9i and 10g Programming Techniques and Solutions now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
