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


When it comes to maintaining a single PostgreSQL cluster with a single source of WAL files, our job is an easy one. Even a small number of streaming replicas are easily managed manually with PostgreSQL-provided tools. However, what happens when we have a large constellation of PostgreSQL servers, such as this?

This diagram represents seven PostgreSQL servers for a single source of data. The Trading server sends its WAL data to a secondary system for safekeeping. One replica subscribes directly to the Trading database, while two others acquire their data through cascading replication. All clones are attached to the WAL archive in case their respective streams get disconnected.

Further complicating the situation, there's an off-site copy of the entire architecture for disaster recovery. Even though the recovery copy in the alternate data center is reduced in terms of capabilities, it still requires several servers for the client applications to run properly. Worse still, in the...