Oracle Distributed Systems

Chapter 9. Oracle Replication Architecture

If you’re going to realize the full potential of Oracle’s advanced replication facilities and simultaneously avoid the pitfalls, you need to understand the architecture on which they are based. If you are new to replication or a bit unclear about how the components work together, this chapter is for you. The following chapters assume an understanding of the concepts discussed here.

What Is Oracle Replication?

Let’s begin with a few simple concepts. Oracle’s replication facility is a collection of tables, PL/SQL packages, and background processes that can automatically replicate data or procedure calls from one database to one or more other databases. Oracle’s replication is built in to the database itself; it is not a separate application or utility like export and import. Depending on the configuration, data can be modified at all sites, or one site can be the sole writer while other sites receive read-only copies of the data. The functionality can accommodate a wide variety of business requirements. These include:

• High availability

• Scalability

• Remote data deployment

• Data extraction and consolidation

We’ll examine the details of implementing these solutions in later chapters.

Note that replicating data is fundamentally different from distributing data. When data is distributed, it may be accessed transparently from multiple locations, but a given table exists in only one location, and that location is responsible for its security and integrity. ...