It's a shame you can't easily add an extensions to most hosted postgres solutions. I hacked on the postgres ltree extension [1] recently, and was amazed at how easy it is to extend functionality of the database, add new types/operators/etc. I think if they were a bit more accessible we'd see them much more. You can even write them in go [2]<p>[1] <a href="https://github.com/postgres/postgres/tree/master/contrib/ltree" rel="nofollow">https://github.com/postgres/postgres/tree/master/contrib/ltr...</a><p>[2] <a href="https://github.com/microo8/plgo" rel="nofollow">https://github.com/microo8/plgo</a>
There's an edX MOOC of a similar title that people here may also may be interested in: <a href="https://www.edx.org/course/hacking-postgresql-data-access-methods" rel="nofollow">https://www.edx.org/course/hacking-postgresql-data-access-me...</a>
From my limited experience diving into the Postgres source code, it's really a treat. Everything is very clearly written and documented. It's pretty easy to read the source code to get an understanding of how components of Postgres work under the hood.