In this chapter, you have already learned that the transaction log of PostgreSQL has all changes made to the database. The transaction log itself is packed into nice and easy-to-use 16 MB segments.

The idea of using this set of changes to replicate data is not farfetched. In fact, it is a logical step in the development of every relational (or maybe even a non-relational) database system. For the rest of this book, you will see in many ways how the PostgreSQL transaction log can be used, fetched, stored, replicated, and analyzed in many different ways.

In most replicated systems, the PostgreSQL transaction log is the backbone of the entire architecture (for synchronous as well as for asynchronous replication).