SQL is query a language that is usually pretty easy to read. However, if people don’t format their queries properly even SQL turns out to be a nightmare. That’s why developers often turn to an SQL beautifier to turn an ugly query into a nicely formatted string. Various tools are available on the web to […]

Version 12 of PostgreSQL is not exactly fresh out of the oven, as the first minor release was already announced. However, I think it’s fair to say that this version can be still considered fresh for most users, and surely only a small percentage of users has upgraded. So I think it makes sense to […]

Image © Laurenz Albe 2019 If you thought that the B-tree index is a technology that was perfected in the 1980s, you are mostly right. But there is still room for improvement, so PostgreSQL v12 (in the tradition of v11) has added some new features in this field. Thanks, Peter Geoghegan! In this article, I […]

Many PostgreSQL database users might have stumbled over the effective_cache_size parameter in postgresql.conf. But how can it be used to effectively tune the database and how can we speed up PostgreSQL using effective_cache_size? This blog will hopefully answer some of my readers’ questions and reveal the hidden power of this secretive setting. RAM, Linux, PostgreSQL […]

OSM to PostGIS – The Basics Ever wondered how to import OSM (OpenStreetMap) data into PostGIS [1] for the purpose of visualization and further analytics? Here are the basic steps to do so. There are a bunch of tools on the market— osm2pgsql; imposm; ogr2org; just to mention some of those. In this article I […]

etcd is one of several solutions to a problem that is faced by many programs that run in a distributed fashion on a set of hosts, each of which may fail or need rebooting at any moment. One such program is Patroni; I’ve already written an introduction to it as well as a guide on how […]

  With the latest major version freshly released, it’s again time to gauge its performance. I’ve already been doing this for years, and I have my scripts ready, so it’s not too much work for me – but rather, for the machines. The v12 release, as always, adds quite a lot of nice stuff. Some […]

After reading this post you will be able to write your first Reinforcement Learning program to solve a real life problem – and beat Google at it. Reinforcement Learning (RL) has gained a lot of attention due to its ability to surpass humans at numerous table games like chess, checkers and Go. If you are […]

© Laurenz Albe 2019   “Durability”, the D of ACID, demands that a committed database transaction remains committed, no matter what. For normal outages like a power failure, this is guaranteed by the transaction log (WAL). However, if we want to guarantee durability even in the face of more catastrophic outages that destroy the WAL, […]

PostgreSQL uses shared_buffers to cache blocks in memory. The idea is to reduce disk I/O and to speed up the database in the most efficient way possible. During normal operations your database cache will be pretty useful and ensure good response times. However, what happens if your database instance is restarted – for whatever reason? […]

Did you know that your temporary tables are not cleaned up by autovacuum? If you did not, consider reading this blog post about PostgreSQL and autovacuum. If you did – well, you can still continue to read this article. Autovacuum cleans tables automatically Since the days of PostgreSQL 8.0, the database has provided this miraculous […]

Parallel queries were introduced back in PostgreSQL 9.6, and the feature has been extended ever since. In PostgreSQL 11 and PostgreSQL 12, even more functionality has been added to the database engine. However, there remain some questions related to parallel queries which often pop up during training and which definitely deserve some clarification. Estimating the […]