Redo and Rollback

Summary

In this chapter, we have taken a look at redo and rollback, and what they mean to the developer. What I have presented here is mostly things for you to be on the look out for, since it is actually the DBAs or SAs who must correct these issues. The most important things to take away from this chapter are the importance of redo and rollback, and the fact that they are not overhead — they are in fact integral components of the database, they are necessary and mandatory. Once you have a good understanding of how they work, and what they do, you’ll be able to make better use of them. Understanding that you are not ‘saving’ anything by committing more frequently than you should (you are actually wasting resources, it takes more CPU, more disk, and more programming), is probably the most important point. Understand what the database needs to do, and then let the database do it.