When I was a teenager I made a search engine and database from scratch, not knowing anything about either. I just wanted to see how far I could get, how fast I could make it, returning somewhat relevant search results.
It's actually very easy to make a fast basic database and search engine, even as an amateur programmer. As long as you understand basic CS algorithms and how to exploit the operating system and hardware, you can put one together in a month or two. Speed is not bad even with high-level languages; something like 250K QPS, back in 2003, on a laptop. Scalability isn't much of an issue either if you shard it. Indexing, locking, and consistency are more complicated than the storage and retrieval parts.
The big problem to overcome is the subjective nature of search. What do I really want to find? How do I find something when I don't know what I'm looking for? How do I get around people trying to game the system? How do I handle complex queries and datasets? That's when it gets orders of magnitude harder.
It's actually very easy to make a fast basic database and search engine, even as an amateur programmer. As long as you understand basic CS algorithms and how to exploit the operating system and hardware, you can put one together in a month or two. Speed is not bad even with high-level languages; something like 250K QPS, back in 2003, on a laptop. Scalability isn't much of an issue either if you shard it. Indexing, locking, and consistency are more complicated than the storage and retrieval parts.
The big problem to overcome is the subjective nature of search. What do I really want to find? How do I find something when I don't know what I'm looking for? How do I get around people trying to game the system? How do I handle complex queries and datasets? That's when it gets orders of magnitude harder.