Issue with Hash Map Space and Performance

Question

I have to store more than 100 millions of key-values in my HashMultiMap (key can have multiple values). Can anybody help me which one is faster for both storing and searching:

Answer 1

I would have a look at leveldb, because it claims to be faster than Kyoto Cabinet. Other interesting libraries are Kyoto Cabinet, and JDBM3.

Those are low level libraries (without support for relational queries or SQL). Some offer transactional support, but I'm not sure if you need it. Still, in-memory hash maps are faster.