LMDB is an embedded key-value storage engine that provides ACID-compliant data persistence. It is a memory-mapped database that utilizes B+ trees to store key-value pairs, ensuring atomicity, consistency, isolation, and durability.
The engine maps files directly into the virtual address space to minimize data copying and system calls. This approach enables high-performance local caching and low-latency data access, specifically optimizing for read-heavy database workflows.
The system implements a transactional model with copy-on-write versioning and single-writer multi-reader locking. These mechanisms allow multiple concurrent read-only transactions to access consistent snapshots without locks while restricting modifications to a single writer.