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

Debugging with strace

Sometimes, the only way to truly observe a server process is by using the kernel itself. This kind of data is invaluable for troubleshooting or research into PostgreSQL activity.

The Linux strace utility provides detailed system trace data for any process or service running on the server. For use with PostgreSQL, this utility means we can target the database itself or any of the background processes it uses for maintenance.

Perhaps, more importantly, we can debug or examine any client connection. Is the network connection permanently hung? Is the client sending thousands of simple SQL requests instead of bulk-handling the results of a single large query? The strace command output is both intricate and verbose. Let's use strace to inspect our server and see what we can discover.

Getting ready

There are certain limitations to using strace. Because of its high-level access to process information, only root-level users are allowed to examine an application's activity. Make...