High-Availability comes with some impact on your architecture choices, in particular when applied to RDBMS such as Postgres. One such impact is the idea of a failover. When implementing database HA, it is usually expected that both the service and the data are maintained available in the face of operational faults. The most common way to implement resilience includes automated (or manual) failover, where a new primary is elected among a list of standby nodes.

In other words, as soon as Postgres High-Availability is implemented, the roles of your Postgres nodes are dynamic. The fact that a given node is a primary or a standby at any given point in time ceases to be relevant to understanding your architecture. In fact, the only thing that’s now given about the role of a node is that it will change. Otherwise you don’t have failover capability, and then, you probably don’t have HA in the first place, right?

In this article we are going to try and understand what having dynamic roles for Postgres nodes in a HA system means.

We just released pg_auto_failover version 1.6.3 on GitHub, and the binary packages should be already available at the usual PGDG and CitusData places, both for debian based distributions and RPM based distributions too.

This article is an introduction to the pg_auto_failover project: we answer the Five W questions, starting with why does the project exist in the first place?

TL;DR pg_auto_failover is an awesome project. It fills the gap between “Postgres is awesome, makes developping my application so much easier, it solves so many problems for me!” and the next step “so, how do I run Postgres in Production?”. If you’re not sure how to bridge that gap yourself, how to deploy your first production system with automated failover, then pg_auto_failover is for you. It is simple to use, user friendly, and well documented. Star it on the pg_auto_failover GitHub repository and get started today. Consider contributing to the project, it is fully Open Source, and you are welcome to join us.

Buckle up, our guide tour is starting now!

The MACI French podcast honoured me with an invitation to a guest appearance on their weekly schedule. As you can imagine, we talked about many things related to PostgreSQL… and also reacted to some newsworthy articles carefully curated by the MACI team. One of the topics we discussed in the podcast started with looking at PostgreSQL through the angle of it being one of the microservices that your application would be composed of.

Among a lot of other changes, the year 2020 brings Online Conferences to us. In the Postgres community too we now record our talks at home and send a video file to be playedto a virtual audience, and sometimes shared later in a platform online. So this year I did participate in Postgres Vision 2020 where I did deliver a talk about The Art of PostgreSQL. This a talk all about the book that I have written and self-publish at The Art of PostgreSQL: learn how to turn thousands of lines of code into simple SQL queries.

Postgres has extensions, and that’s awesome! Of course as the author of CREATE EXTENSION I’m a little biased… just remember that the ability to extend Postgres is way more than just this command. The whole database system has been design from the ground up to allow for extensibility. Parts of the design is to be found in the way you can register new objects at runtime: functions of course, and also data types, operators, index support structures such as operator classes and families, even index access methods!

Today’s article shows a query that you can use to list those tables in your schemas that are using a data type which is provided by an extension.

PostgreSQL connection strings embedded in your application can take two different forms: the key-value notation or the postgresql:// URI scheme. When it comes to using psql though, another form of connection string is introduced, with command line options -h -p -U and environment variable support.

In this short article you will learn that you can use either of the three different forms in psql and thus easily copy & paste you application connection string right at the console to test it!