Concurrency and Multiversioning

As stated in the last chapter, one of the key challenges in developing multiuser, database-driven applications is to maximize concurrent access but, at the same time, ensure that each user is able to read and modify the data in a consistent fashion. In this chapter, we’re going to take a detailed look at how Oracle achieves multiversion read consistency and what that means to you, the developer. I will also introduce a new term, write consistency, and use it to describe how Oracle works not only in a read environment with read consistency, but also in a mixed read and write environment.

What Are Concurrency ...

Get Expert Oracle Database Architecture, Third Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.