In the previous chapter, we dealt with various replication concepts. That was meant to be more of a theoretical overview to sharpen your senses for what is to come, and was supposed to introduce the topic in general.
In this chapter, we will move closer to practical solutions, and you will learn 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 in order to fully understand replication. You will learn the following topics in this chapter:
How PostgreSQL writes data
Which memory and storage parameters are involved
How writes can be optimized
How writes are replicated
How data consistency can be ensured
In this chapter, you will also learn about replication slots and logical decoding. Once you have completed reading this...