C++ map insertion and lookup performance and storage overhead

Question

I would like to store a mapping of an integer key to a float value in-memory.

I have roughly 130 million keys (and, accordingly, 130 million v

Answer 1

If your keys are unchanging, you might consider a perfect hash function as an alternative to a standard container.

I don't know what obstacles you'll run into with a dataset of that size, but it might be worth spending a few minutes experimenting.