Optimize read/write huge data (C++)

Question

I am looking to optimize reading/writing huge data for a C++ simulation application. The data termed as a \"map\" essentially consists of integers, doubles, floats and a single

Answer 1

"millions" maps do not sound like a lot of data. What prevents you from keeping all data in memory?

Another option is to use some standard file format suitable for your needs e.g., sqlite (use SQL to store/retrieve data) or some specialized format like hdf5 or define you own format using something like Google Protocol Buffers.