Believe me I am aware. I am one of those who implemented their own index for a code search engine :) I did it for my own learning, but find it interesting because something like elastic with trigrams can get you very close, albeit at a far greater cost.
I'm reading your blog posts about building your own index now.
I started writing my own very simple index and search engine, but quickly decided to just use ClickHouse via https://tinybird.co as my backend (Serverless SQL with automatic APIs is pretty sweet) because I wanted to build out the product side of things and my data is really small, so I felt like it was going to be a lot of effort for little reward.
Maybe one day I will need to write a custom index or search engine that actually scales though :).
