I spent a couple years managing a Postgres cluster with a petabyte of data. I wrote a couple blog posts from my work then[0][1]. I also wrote dozens of posts on the Postgres internals[2]. I've also given talks on how to generate fractals with SQL[3] and how to write a lisp interpreter in SQL[4].
[0] https://www.heap.io/blog/testing-database-changes-right-way
[1] https://www.heap.io/blog/analyzing-performance-millions-sql-...
[2] https://malisper.me/table-of-contents/