Which Is Better for a Key-Value Database: One File or Two?

Are you actually planning to build this, or is it more academic curiosity? If you're serious, try creating a million entries and comparing the two approaches. If your data isn't too large, just loading everything into RAM from one file will make retrieval pretty speedy regardless of the format. But for anything serious, you should definitely consider a more robust database engine to handle storage efficiently, especially if you plan to write data frequently.

It really depends on your use case, but generally, if you're just dealing with plain text files, using one file might slow things down if your dataset grows large. A lot of proper databases like LMDB or SQLite use sophisticated data structures that handle queries more efficiently. If your values are much larger than your keys and you mostly add new entries rather than update them, using two files might help reduce IO by directing the keys to an indexed data structure that points to values. But that's getting pretty advanced for a fun project! For practical testing, you could create a realistic dataset and benchmark it with tools like timeit to compare read and write speeds on both setups.

Honestly, if you can use a proper database, that would be the way to go. But if you're just having fun with this project, I'd stick to one file for simplicity. That way, you won't accidentally mess up line numbers if you ever need to add or delete entries. And if speed is a big concern, databases will generally outperform flat file operations.