Book Image

PostgreSQL High Availability Cookbook - Second Edition

By : Shaun Thomas
Book Image

PostgreSQL High Availability Cookbook - Second Edition

By: Shaun Thomas

Overview of this book

Databases are nothing without the data they store. In the event of a failure - catastrophic or otherwise - immediate recovery is essential. By carefully combining multiple servers, it’s even possible to hide the fact a failure occurred at all. From hardware selection to software stacks and horizontal scalability, this book will help you build a versatile PostgreSQL cluster that will survive crashes, resist data corruption, and grow smoothly with customer demand. It all begins with hardware selection for the skeleton of an efficient PostgreSQL database cluster. Then it’s on to preventing downtime as well as troubleshooting some real life problems that administrators commonly face. Next, we add database monitoring to the stack, using collectd, Nagios, and Graphite. And no stack is complete without replication using multiple internal and external tools, including the newly released pglogical extension. Pacemaker or Raft consensus tools are the final piece to grant the cluster the ability to heal itself. We even round off by tackling the complex problem of data scalability. This book exploits many new features introduced in PostgreSQL 9.6 to make the database more efficient and adaptive, and most importantly, keep it running.
Table of Contents (18 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Setting up Slony

While there are a few logical asynchronous replication systems for PostgreSQL, Slony-I (Slony in short) was the first to gain wide adoption. Why would we use Slony when PostgreSQL already has replication? Currently, PostgreSQL replication can only copy the entire installation. Every database, schema, table, and user is copied at the binary level. In effect, streaming replication creates perfect clones of PostgreSQL servers.

Slony is very different. It is designed to copy tables only, capturing changes on a master server and sending them to one or more subscribers. If you want this type of replication, this section will provide a basic installation recipe designed for one master and one subscriber.

Getting ready

In order to install Slony, we will need the source code. At the time of writing this book, the latest version available is 2.2.5. You can obtain a copy of the source at this URL:

We only need the primary source package, but feel...