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 […]

Having recently witnessed quite an ingenious hack to implement some good old “println” style development debugging from stored procedures into a file, it prompted me to post knowledge to the Interwebs on two other ways how such a goal can be implemented more transparently. Also, with help of some other good old legacy technology in […]