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 pglogical

PostgreSQL 9.4 introduced a feature called replication slots. This essentially makes it possible to decode the transaction log and extract database traffic for remote replay at a logical level. Unlike standard replication that requires the primary and replica to be identical, slots can be mined for specific information relevant to user needs.

One of the first PostgreSQL extensions to make use of replication slots is pglogical by 2ndQuadrant. Like Slony, Bucardo, and Londiste, pglogical can copy individual tables from one database to another. Unlike those other pieces of software, it does so without encumbering tables with performance-robbing triggers, and does not rely on an external daemon to coordinate data copy streams.

Let's get it running.

Getting ready

The latest version of pglogical at the time of writing this book is 1.2.1. Obtain a copy of the source code from the following URL:

The pglogical extension also requires several...