PostgreSQL
Visually debugging PGX extensions
Using Visual Studio Code and LLDB to debug PGX extensions
Rust spoils me, I rarely need to reach for a debugger thanks to structured logging via tracing and errors with spantraces thanks to eyre. When I do find myself wanting to really dig my grubby little paws into some code, configuring the debugger targets can feel intimidating.
Experience has taught me that I can conquer intimidating things though, and sometimes that is best done with a little help. While hacking on a pgx bug, I realized I was using a newly installed system, and needed to reconfigure my debugger settings.
This made a good opportunity for me to share with you! This short article will cover how to configure Visual Studio Code with CodeLLDB so you can visually debug your pgx extensions. This includes being able to step into the pgx or postgres sources. While the instructions may be Arch Linux specific, they should be able to be adapted to a different Linux.
PostgreSQL Aggregates with Rust
Writing custom Aggregates for statistical or analytical purposes.
Reaching for something like SUM(vals) or AVG(vals) is a common habit when using PostgreSQL. These aggregate functions offer users an easy, efficient way to compute results from a set of inputs.
How do they work? What makes them different than a function? How do we make one? What kinds of other uses exist?
We'll explore creating some basic ones using SQL, then create an extension that defines aggregates in Rust using pgx 0.3.0's new aggregate support.
Forging SQL from Rust
How pgx creates PostgreSQL extension SQL definitions that bind to Rust.
PostgreSQL offers an extension interface, and it's my belief that Rust is a fantastic language to write extensions for it. Eric Ridge thought so too, and started pgx awhile back. I've been working with him to improve the toolkit, and wanted to share about one of our latest hacks: improving the generation of extension SQL code to interface with Rust.
This post is more on the advanced side, as it assumes knowledge of both Rust and PostgreSQL. We'll approach topics like foreign functions, dynamic linking, procedural macros, and linkers.
Hierarchical Structures in PostgreSQL
Modelling hierarchical/team/categorical/tag data with arbitrary depths.
It's a common pattern: a database developer at a startup is probably on the Product subteam of the Engineering team at their company. In a department store, shoes are a subcategory of clothing, while your favorite thermos is probably in the travel department.
In any Github organization, there are teams within teams within teams. In any large department store there are categories deeply nested. In any recipe book, there are many ways to classify food.
So how can we model them?