C++ in-memory Key-Value stores

Question

I'm looking for suggestions regarding in-memory key-value store engines or libraries, that have C++ interfaces or that are written in C++.

I'm looking for solutions that can scale without any problems to about 100mill key-value pairs and that are compatible/compilable on linux and win32/64

Answer 1

How about std::map?
http://cplusplus.com/reference/stl/map/

Answer 2

If you really need to store such amount of pairs in memory consider this Sparse Hash. It has special implementation which is optimized for low memory consumption.

Answer 3

std::map is fine given that size of key and value is small and the available memory is large ( for about 100million pairs). If its not the case, and you want to run a program over the key-value pairs, consider using a standard MapReduce API. Map Reduce is specifically meant to be used on distributed systems and process large data specially key-value pairs. Also there are nice C++ APIs for Map Reduce. http://en.wikipedia.org/wiki/MapReduce