Book Image

PostgreSQL 12 High Availability Cookbook - Third Edition

By : Shaun Thomas
Book Image

PostgreSQL 12 High Availability Cookbook - Third Edition

By: Shaun Thomas

Overview of this book

Databases are nothing without the data they store. In the event of an outage or technical catastrophe, immediate recovery is essential. This updated edition ensures that you will learn the important concepts related to node architecture design, as well as techniques such as using repmgr for failover automation. From cluster layout and hardware selection to software stacks and horizontal scalability, this PostgreSQL cookbook will help you build a PostgreSQL cluster that will survive crashes, resist data corruption, and grow smoothly with customer demand. You’ll start by understanding how to plan a PostgreSQL database architecture that is resistant to outages and scalable, as it is the scaffolding on which everything rests. With the bedrock established, you'll cover the topics that PostgreSQL database administrators need to know to manage a highly available cluster. This includes configuration, troubleshooting, monitoring and alerting, backups through proxies, failover automation, and other considerations that are essential for a healthy PostgreSQL cluster. Later, you’ll learn to use multi-master replication to maximize server availability. Later chapters will guide you through managing major version upgrades without downtime. By the end of this book, you’ll have learned how to build an efficient and adaptive PostgreSQL 12 database cluster.
Table of Contents (17 chapters)

Using sequences safely

Sequences and identity columns within a multi-master context are especially prone to complications. PostgreSQL itself is essentially unaware of the presence of other PostgreSQL nodes that may refer to the same sequences, and each node operates independently of the others in that regard.

As a result, each new incremental value from a standard sequence is arbitrary and could result in duplicate values on nodes. This would be a disaster if we are using them for a primary key, as any conflicts here would result in lost data.

This recipe will demonstrate how to safely use sequences with BDR and prevent any node from producing conflicting values.

Getting ready

In order to apply this recipe, we should begin...