Partitioning is one of the most desired features of PostgreSQL, widely adopted by developers. This is not only true for in PostgreSQL 15, but also for older versions which did not provide as many features as the latest version of the database. That’s why you should know not only how to properly partition tables, but […]

In PostgreSQL 15, a fundamental change took place which is relevant to every user who happens to work with permissions: The default permissions of the public schema have been modified. This is relevant because it might hurt you during application deployment. You need to be aware of how it may affect you. Creating users Many […]

Indexing is the key to good performance. However, people often ask: Is there an alternative to btree indexing? Can we make indexes in PostgreSQL smaller? Can we create indexes in PostgreSQL faster? And how can we index in a data warehouse? This blog will answer all those questions and show which options you have to […]

pgbouncer is one of the most widely used tool for connection pooling. At CYBERTEC, we’ve successfully deployed it in many different situations. It has proven to be reliable as well as useful. Before we dive into different pooling modes and their implications, why do we need a connection pooler in the first place? The reason […]

Did you ever wonder why VACUUM does not make your PostgreSQL tables smaller? Did you ever wonder why VACUUM does not shrink data files? Well, maybe this is the article you have been looking for. The point is: usually, space is not returned to the operating system after a cleanup and it is important to […]

What is LISTEN and NOTIFY? LISTEN / NOTIFY is a feature that enables users to listen to what goes on in the database. It is one of the oldest functionalities in PostgreSQL and is still widely used. The main question is: What is the purpose of the asynchronous query interface (LISTEN / NOTIFY), and what […]

Sequences are a core feature of SQL. However, some users are tempted to implement sequences to generate invoices. That’s dangerous and should be avoided. The core question is: Why? What’s the problem with using database-side sequences to put unique invoice numbers to send to clients? Let’s dive in and find out. Getting started with CREATE […]

A join is a concept in IT which is widely used and often referred to but rarely really understood. What are the differences between inner joins, outer joins, semi joins and so on? Let’s shed some light on them and see how inner and outer joins really work. Producing sample data Before we can get […]

serial is a popular pseudo data type in PostgreSQL which is often used to generate auto-increment columns. However, this can lead to issues which are often underestimated. So what is the problem? Some of you might have already seen the following error message in real life: What happened here is that the underlying integer column […]

Running ALTER TABLE … ADD COLUMN can have side effects which have the potential to cause serious issues in production. Changing data structures is an important issue and happens often, therefore it’s important to understand what is really going on. Let’s dive in and see how to run ALTER TABLE … ADD COLUMN in a […]

I’ve recently seen some really broad tables (hundreds of columns) in a somewhat inefficiently structured database. Our PostgreSQL support customer complained about strange runtime behavior which could not be easily explained. To help other PostgreSQL users in this same situation, I decided to reveal the secrets of a fairly common performance problem many people don’t […]

Bonus cards, “Miles & more”, bonus points – don’t we all love and hate them at the same time? Recently we had an interesting use case which made me think about sharing some of the techniques we used in this area to reduce client code by writing some clever SQL. This post will show you […]