A few years ago, I wrote a short post on a similar topic; since then, I’ve often seen that the whole concept of suggesting to do more INSERT-s in critical parts of the code seems pretty strange to most customers. It’s even alien to those who are not new to databases in general. So I […]

As you probably know, pg_timetable is the advanced PostgreSQL cron compatible scheduler already released! Usually, any major release introduces absolutely new functionality as well as some backward incompatibilities. However, the only backward incompatibility present in this release is that the base task SHELL changed its name to PROGRAM. Yes, that’s all. 🙂 Now, let’s check […]

PostgreSQL is a rock-solid database that is widely used for highly critical applications. Bugs are rarely seen. However, everything fails once in a while. The entire stack (hardware, operating system, etc) are subjected to occasional failure. Thus one has to prepare for that. The main problem is: How can one simulate failure? In many cases […]

© Laurenz Albe 2020 Streaming replication in PostgreSQL is a well-established master-slave replication technique. It is simple to set up, stable and performs well. So many people are surprised when they learn about replication conflicts — after all, the standby server is read-only. This article describes replication conflicts and tells you how to deal with […]

Patroni has dramatically simplified the setup of the PostgreSQL High-Availability cluster. Personally I consider Patroni to be by far the best tool out there to cluster PostgreSQL and to ensure HA in the most reliable and straightforward way possible. The main questions asked by many people are: How can you make a PostgreSQL cluster transparent? […]

In SQL, the concept of foreign keys is an important one that can be found in all professional databases used in the industry. The core idea is to prevent your PostgreSQL database from storing inconsistent data by enforcing constraints ensuring the correctness of your tables (at least as far as relations between objects are concerned). […]

To dig a bit deeper into zheap and PostgreSQL storage technology in general I decided to provide some more empirical information about space consumption. As stated in my previous blog post about zheap is more efficient in terms of storage consumption. The reasons are: The tuple header is much smaller Alignment has been improved The […]

Temporary tables have been around forever and are widely used by application developers. However, there is more to temporary tables than meets the eye. PostgreSQL allows you to configure the lifespan of a temporary table in a nice way and helps to avoid some common pitfalls. CREATE TEMPORARY TABLE … By default, a temporary table […]

© Laurenz Albe 2020 HOT updates are not a new feature. They were introduced by commit 282d2a03dd in 2007 and first appeared in PostgreSQL 8.3. But since HOT is not covered by the PostgreSQL documentation (although there is a README.HOT in the source tree), it is not as widely known as it should be: Hence […]

© Laurenz Albe 2020 In many PostgreSQL databases, you never have to think or worry about tuning autovacuum. It runs automatically in the background and cleans up without getting in your way. But sometimes the default configuration is not good enough, and you have to tune autovacuum to make it work properly. This article presents […]

© Laurenz Albe 2020 Many people consider recursive queries a difficult topic. Still, they enable you to do things that would otherwise be impossible in SQL. This articles gives a simple introduction with examples and shows the differences to Oracle’s implementation of recursive queries. Common table expressions (WITH clauses) A common table expression (CTE) can […]

¡Hola, queridos amigos! We’ve released several valuable features for pg_timetable in May. It’s summer already, and time is flying fast! I hope all of you are well and safe, as well as your families and friends. Here I want to introduce what’s new and how that is useful briefly. If you are unfamiliar with pg_timetable, […]