lmdb

OpenLDAP Lightning Memory-Mapped Database

LMDB is an ultra-fast, ultra-compact key-value data store developed by Symas for the OpenLDAP Project. It uses memory-mapped files, so it has the read performance of a pure in-memory database while still offering the persistence of standard disk-based databases, and is only limited to the size of the virtual address space, (it is not limited to the size of physical RAM). LMDB was originally called MDB, but was renamed to avoid confusion with other software associated with the name MDB.