Get the newest tricks and useful tips about the world of PostgreSQL and Data Science! Our authors and technicians share their knowledge to keep you going with your data.
Searching for a quick tip? Check out our microblog, where we share our insights as they happen – short and simple!
HOT updates in PostgreSQL for better performance
© 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 […]
Generating a normal distribution in SQL
SQL and PostgreSQL are perfect tools to analyze data. However, they can also be used to create sample data which has to possess certain statistical properties. One thing many people need quite often is a normal distribution. The main question therefore is: How can one create this kind of sample data? Tablefunc: Creating normal distributions […]
PostgreSQL vs PostGreSQL vs Postgre vs Oracle vs all the rest
Is it Postgre, PostGreSQL, Postgres or PostgreSQL? We have all seen a couple of wrong ways to spell “PostgreSQL”. The question therefore is: How can one find data even if there are typos? In PostgreSQL there are various solutions to the problem. Depending on what kind of search you need you can choose between various […]
Tuning PostgreSQL autovacuum
© 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 […]
PostgreSQL: GROUP BY expression
GROUP BY is nothing new and is available in any relational database I am aware of. It is an integral part of SQL and PostgreSQL but what many people might not know is the fact that GROUP BY can do more than just group by simple fields. You can use expressions to group in an […]
Understanding recursive queries in PostgreSQL
© 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 […]
A quick pg_stat_statements troubleshooting hack
An introductory story (with some slight “drama” added for fun) from those good old days of on-site consulting 🙂 So…I’m at a client where the database is not behaving nicely among other things…what a crappy DB product indeed I hear, it gets cranky every morning although there should be a constant workload and is saturating […]
effective_cache_size: A practical example
A lot has been written about effective_cache_size in postgresql.conf and about PostgreSQL performance in general. However, few people know what this famous parameter really does. Let me share some more insights. What the PostgreSQL optimizer does The idea behind SQL is actually quite simple: The end user sends a query and the optimizer is supposed […]
What is fillfactor and how does it affect PostgreSQL performance?
Recently I was asked if there’s a rule of thumb / best practice for setting the fillfactor in Postgres – and the only answer I could give was to decrease it “a bit” if you’re doing lots and lots of updates on some table. Good advice? Well it could be better of course – this […]
PostgreSQL: More performance for LIKE and ILIKE statements
LIKE and ILIKE are two fundamental SQL features. People use those things all over the place in their application and therefore it makes sense to approach the topic from a performance point of view. What can PostgreSQL do to speed up those operations and what can be done in general to first understand the problem […]
pgwatch2 v1.8.0 released
After exactly half a year (seems to be a pattern already) since the last major release of pgwatch2 Open Source PostgreSQL monitoring tool, I’m glad to announce that another set of useful features and improvements have found their way into the pgwatch2 code repository! New version is incremented to v1.8.0 and content wise it’s mostly […]
pg_timetable: start-up improvements
¡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, […]