Lightning Memory-Mapped Database: Difference between revisions

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There are wrappers for several programming languages, such as C++,<ref>[https://github.com/bendiken/lmdbxx LMDB C++11 wrapper], 2015-04</ref><ref>[https://code.google.com/p/libglim/source/browse/trunk/mdb.hpp LMDB C++ wrapper], 2012-11.</ref> Java,<ref>[https://github.com/lmdbjava/lmdbjava LmdbJava], 2019-04</ref> Python,<ref>[https://github.com/dw/py-lmdb/ LMDB Python wrapper], 2013-02</ref><ref>[http://lmdb.readthedocs.org py-lmdb]. Retrieved on 2014-10-20.</ref> Lua,<ref>[https://github.com/shmul/lightningdbm LMDB Lua wrapper], 2013-04.</ref> Rust,<ref>[https://github.com/meilisearch/heed typed LMDB Rust wrapper], 2023-01</ref><ref>[https://github.com/mozilla/rkv high-level Rust wrapper], 2022-12</ref> Go,<ref>[https://github.com/bmatsuo/lmdb-go LMDB Go wrapper], 2013-03</ref> Ruby,<ref>[https://github.com/minad/lmdb LMDB Ruby wrapper], 2013-02</ref> Objective C,<ref>[https://github.com/rbartolome/LMDBKit LMDB Objective-C wrapper], 2013-04</ref> Javascript,<ref>[https://github.com/Venemo/node-lmdb LMDB Node.js wrapper], 2013-05</ref> C#,<ref>[https://github.com/ilyalukyanov/Lightning.NET LMDB .Net wrapper], 2013-06</ref> Perl,<ref>[http://search.cpan.org/dist/LMDB_File/ LMDB Perl wrapper], 2013-08</ref> PHP,<ref>[https://github.com/mpremus/lmdb-php LMDB PHP wrapper], 2015-04</ref> Tcl<ref>[https://core.tcl.tk/jenglish/gutter/packages/lmdb.html tcl-lmdb], 2015-11</ref> and Common Lisp.<ref>[http://eudoxia.me/article/lmdb-from-common-lisp Using LMDB from Common Lisp], 2016-04</ref> A complete list of wrappers may be found on the main web site.<ref>{{cite web|url=https://www.symas.com/symas-lmdb-tech-info|title=Symas LMDB Tech Info}}</ref>

Howard Chu ported [[SQLite]] 3.7.7.1 to use LMDB instead of its original [[B-tree]] code, calling the end result SQLightning.<ref>{{cite web|url=http://gitorious.org/mdb/sqlightning|title=gitorious.org Git - mdb:<nowiki />sqlightning.git/summary|website=gitorious.org|accessdate=8 May 2017|archive-url=https://web.archive.org/web/20130809145553/http://gitorious.org/mdb/sqlightning|archive-date=9 August 2013|url-status=live}}</ref> One cited insert test of 1000 records was 20 times faster (than the original SQLite with its B-Tree implementation).<ref>[http://pastebin.com/B5SfEieL SQLightning tests].</ref> LMDB is available as a backing store for other open source projects including Cyrus SASL,<ref>{{cite web|url=http://cyrusimap.web.cmu.edu/|title=Cyrus IMAP — Cyrus IMAP 3.0.1 (stable) documentation|website=cyrusimap.web.cmu.edu|accessdate=8 May 2017|url-status=dead|archive-url=https://web.archive.org/web/20170430023937/http://cyrusimap.web.cmu.edu/|archive-date=30 April 2017}}</ref> Heimdal Kerberos,<ref>{{cite web|url=http://h5l.org/|title=Heimdal|website=h5l.org|accessdate=8 May 2017}}</ref> and OpenDKIM.<ref>{{cite web|url=http://www.opendkim.org/|title=OpenDKIM|website=www.opendkim.org|accessdate=8 May 2017}}</ref> It is also available in some other NoSQL projects like MemcacheDB <ref>{{cite web|url=https://gitorious.org/mdb/memcachedb|title=gitorious.org Git - mdb:<nowiki />memcachedb.git/summary|website=gitorious.org|accessdate=8 May 2017}}</ref> and Mapkeeper.<ref>{{cite web|url=https://github.com/m1ch1/mapkeeper/|title=GitHub - m1ch1/mapkeeper: Thrift based key-value store with various storage backends, including MySQL, Berkeley DB, and LevelDB.|website=github.com|url-status=dead|archive-url=httphttps://web.archive.org/web/20160209024233/https://github.com/m1ch1/mapkeeper/|archive-date=16 Feb 2016}}</ref> LMDB was used to make the in-memory store [[Redis]] persist data on disk. The existing back-end in [[Redis]] showed pathological behaviour in rare cases, and a replacement was sought. The baroque API of LMDB was criticized though, forcing a lot of coding to get simple things done. However, its performance and reliability during testing was considerably better than the alternative back-end stores that were tried.<ref>{{cite web|url=http://www.anchor.com.au/blog/2013/05/second-strike-with-lightning/|title=Second Strike With Lightning|publisher=Anchor|date=2013-05-09}}</ref>

An independent third-party software developer utilised the [[Python (programming language)|Python]] bindings to LMDB<ref>{{cite web | url=http://lmdb.readthedocs.org|title=Python bindings to LMDB}}</ref> in a high-performance environment and published, on the technology news site [[Slashdot]], how the system managed to successfully sustain 200,000 simultaneous read, write and delete operations per second (a total of 600,000 database operations per second).<ref>{{cite web | url=http://developers.slashdot.org/story/14/10/17/1547222/python-lmdb-in-a-high-performance-environment|title=Python-LMDB in a high-performance environment on Slashdot}}</ref><ref>{{cite web | url=http://lkcl.net/reports/python.lmdb.html|title=Open letter to Howard Chu and David Wilson regarding Python-LMDB}}</ref>