postgresql

Nowadays it’s not uncommon to deal with machines with hundreds of GB of RAM.

Abundant memory can give PostgreSQL a massive performance boost. However things work slightly different than you may expect.

Let’s find out!

For obvious reason the FOSDEM this year is an online event. The staff is building from scratch an infrastructure in order to deliver the speaker’s videos in a virtual environment.

The catch is that all the talks must be pre recorded and uploaded via pentabarf, the software historically used by FOSDEM to manage the talk submissions.

What follows is my experience in recording,uploading and submitting the video for my upcoming talk.

When in a pl/pgsql function there is an exception then the function stops the execution and returns an error. When this happens all the changes made are rolled back.

It’s always possible to manage the error at application level, however there are some cases where managing the exception inside the function it may be a sensible choice. And pl/pgsql have a nice way to do that. The EXCEPTION block.

However handling the exception inside a function is not just a cosmetic thing. The way the excepion is handled have implications that may cause issues.

With PostgreSQL 12 the generated columns are now supported natively. Until the version Postgresql 11 it were possible to have generated columns using a trigger.

In this post we’ll see how to configure a generated column via trigger and natively then we’ll compare the performances of both strategies.

The transactional model has been in PostgreSQL since the early versions. In PostgreSQL its implementation follows the guidelines of the SQL standard with some notable exceptions.

When designing an application it’s important to understand how the concurrent access to data happens in order to avoid unexpected results or even errors.

In the previous post we modified the apt role for controlling the setup in a declarative way. Then we added a ssh role for configuring the three devuan servers. The role is used to configure the server’s postgres process owner for ssh passwordless connection.

In this tutorial we’ll complete the setup for the postgres user and then we’ll configure the database clusters with a new role.

Today is two years since I started working on pg_chameleon. Back in 2016 this commit changed the project’s license from GPL v2 to the 2 clause BSD and the project’s scope, which became a MySQL to PostgreSQL replica system. Since then I learned a lot of lessons, made several mistakes and worked out solutions which resulted in a decent tool for bridging two different universes. Writing a replica system is a very complex task.

In the previous post we configured three devuan servers from scratch using ansible adding the pgdg repository to the apt sources and installing the PostgreSQL binaries.

This tutorial will revisit the apt role’s configuration and will introduce a new role for configuring the postgres operating system’s user for passwordless ssh connections to each other server.

The ansible is a fictional device invented by Ursula K. Le Guin. The ansible allows fast communication between two points across the space, regardless of the distance.

It doesn’t surprise that the Red Hat’s ansible shares the same name as it gives a simple and efficient way to manage servers and automate tasks, yet remaining very lightweight with minimal requirements on the target machines.

In the previous post we introduced the PostgreSQL’s dependency system.

At first sight the implementation can look like a maze where the succession of relationships are not clear.

This post will try to give a practical example to show how pg_depend can act like an Ariadne’s thread in order to resolve the dependencies.

The scenario presented is very simple but can be used as a starting point for more complex requirements.