If you're diving into Postgres and want to better understand how it works under the hood, there is a great talk from PGConf Silicon Valley 2016 titled "How does PostgreSQL actually work" on YouTube: https://www.youtube.com/watch?v=OeKbL55OyL0
Sort of out of topic but this article is nicely illustrated using Excalidraw. Can't state how great that software is for diagrams, workflows, HLDs, UI concepts, etc.
The article looks 10x more approachable as a result.
Agreed! Just came hear to say the exact same thing. Excalidraw (https://excalidraw.com/) is great and I've been really enjoying using it for the past few months, it's great for just throwing together a handful of rough diagrams over zoom to help illustrate code review meetings