tokyocabinet

Tokyo Cabinet is a library of routines for managing a database. It is the
successor of QDBM. Tokyo Cabinet runs very fast. For example, the time required
to store 1 million records is 1.5 seconds for a hash database and 2.2 seconds
for a B+ tree database. Moreover, the database size is very small and can be up
to 8EB. Furthermore, the scalability of Tokyo Cabinet is great.