Chapter 2. Understanding the PostgreSQL Transaction Log
In the previous chapter, we have dealt with various replication concepts. It was meant to be more of a theoretical overview to sharpen your senses for what is to come and it was supposed to introduce you to the topic in general.
In this chapter, we will move closer to practical solutions and learn about how PostgreSQL works internally and what it means for replication. We will see what the so called transaction log (XLOG) does and how it operates. The XLOG is the very backbone of the PostgreSQL-onboard replication machinery. It is essential to understand how this part works.
How PostgreSQL writes data
PostgreSQL replication is all about writing data. Therefore, the way PostgreSQL writes a chunk ...