It's dangerous to go alone. Take this for all things Postgres.
I believe I found this this talk in the comment section of a Hacker News post. I first watched the 2014 version of it. Since then I found out that Christophe Pettus gives this talk yearly.
It’s a long talk, but he talks about almost everything there is to know about Postgres. For advanced stuff he gives just enough starting points for figuring it out yourself.
Watch out! The slides links in the video description don’t work. But you can find them on thebuild.com.
The talk is PostgreSQL Proficiency for Python People by Christoph Pettus.