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Embedded Database LMDB

An ultra-fast, ultra-compact, crash-proof, key-value, embedded data store

Lightning Memory-Mapped Database

Symas LMDB is an extraordinarily fast, memory-efficient database we developed for the OpenLDAP Project. With memory-mapped files, LMDB has the read performance of a pure in-memory database while retaining the persistence of standard disk-based databases.

Bottom line, 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.

Explore Capabilities

Ordered-map interface

      keys are always sorted; range lookups are supported
Fully transactional

      full ACID semantics with MVCC
Reader/writer transactions

      readers don’t block writers; writers don’t block readers
Fully serialized writers

      writes are always deadlock-free
Extremely cheap read transactions

      can be performed using no mallocs or any other blocking calls
Multi-thread and multi-process concurrency supported

      environments may be opened by multiple processes on the same host
Multiple sub-databases may be created

      transactions cover all sub-databases

      allows for zero-copy lookup and iteration

      no external process or background cleanup or compaction required

      no logs or crash recovery procedures required
No application-level caching

      LMDB fully exploits the operating system’s buffer cache
32KB of object code and 6KLOC of C

      fits in CPU L1 cache for maximum performance

Where To Get It

The source is managed by Symas’s gitlab repo:

Symas LMDB Support

Symas offers fixed-price, Gold support or Enterprise source level support to those using LMDB in their applications. Please contact Sales by phone or email for additional information.


Search the discussions on the OpenLDAP mailing lists.

Development occurs in the OpenLDAP Project‘s git repo in the mdb.master branch. A clone of just the LMDB code is also available on Github.

Symas LMDB Tech Info

Symas LMDB has been written about, talked about, and utilized in a variety of impressive products and publications. We invite you to learn more on this specific “Technical Information” page.

Porting and Professional Services

Thinking about switching your application to LMDB? Call us. We will be happy to provide developer support or porting services to help you transition your application to LMDB.

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