Love it! Need better ANNs approaches in databases, using external servers such as Milvus, faiss is a pita
related: https://github.com/netrasys/pgANN
related: https://github.com/netrasys/pgANN
It's still loaded from a file, but heavily uses memory-mapping and caching to be speedy and not overload your RAM immediately. And in production scenarios, multiple worker processes can share that memory due to the memory mapping.
Granted it's read-only, so might not be exactly what you are looking for.
Disclaimer: I'm the author.
PS: I work there