PostgreSQL: You might need to increase max_locks_per_transaction
“out of shared memory”: Some of you might have seen that error message in PostgreSQL already. But what does it really mean, and how can you prevent it? The problem is actually not as obscure as it might seem at first glance. max_locks_per_transaction is the critical configuration parameter you need to use to avoid trouble. […]
Setting PostgreSQL configuration parameters
A lot has been written about configuring postgresql.conf, postgresql.auto.conf and so on. However, sometimes it requires to take a second look in order to understand, how PostgreSQL really handles configuration parameters. You will notice that PostgreSQL configuration offers more than meets the eye at first glance. So let us dive into PostgreSQL GUCs and configuration […]
Abusing PostgreSQL as an SQL beautifier
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 […]
effective_cache_size: What it means in PostgreSQL
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 […]
Prewarming PostgreSQL I/O caches
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? […]
What is autovacuum doing to my temporary tables?
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 […]
How PostgreSQL estimates parallel queries
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 […]
Fixing track_activity_query_size in postgresql.conf
Many of you might have wondered why some system views and monitoring statistics in PostgreSQL can contain incomplete query strings. The answer is that in PostgreSQL, it’s a configuration parameter that determines when a query will be cut off: track_activity_query_size. This blog post explains what this parameter does and how it can be used to […]
Using “Row Level Security” to make large companies more secure
Large companies and professional business have to make sure that data is kept secure. It is necessary to defend against internal, as well as external threats. PostgreSQL provides all the necessities a company needs to protect data and to ensure that people can only access what they are supposed to see. One way to protect […]
PostgreSQL Row Level Security, views and a lot of magic
Row Level Security (RLS) is one of the key features in PostgreSQL. It can be used to dramatically improve security and help to protect data in all cases. However, there are a couple of corner cases which most people are not aware of. So if you are running PostgreSQL and you happen to use RLS […]
Timeseries: EXCLUDE TIES, CURRENT ROW and GROUP
Windowing functions and analytics have been around for quite some time and many people already make use of this awesome stuff in the PostgreSQL world. Timeseries are an especially important area in this context. However, not all features have been widely adopted and thus many developers have to implement functionality at the application level in […]
PostgreSQL: Trivial timeseries examples
Timeseries are an increasingly important topic – not just in PostgreSQL. Recently I gave a presentation @AGIT in Salzburg about timeseries and I demonstrated some super simple examples. The presentation was well received, so I decided to share this stuff in the form of a blog PostgreSQL, so that more people can learn about windowing […]