LMDB - Lightning Memory-mapped Database

LMDB is an extraordinarily fast, memory-efficient database developed for the Symas OpenLDAP Project. With memory-mapped files, it has the read performance of a pure in-memory database while retaining the persistence of standard disk-based databases. With only 32KB of object code, LMDB may seem tiny. But it’s the right 32KB. Compact and efficient are two sides of a coin; that’s part of what makes LMDB so powerful.