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Memcached (pronunciation: mem-cash-dee) is a general-purpose distributed memory caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in RAM to reduce the number of times an external data source (such as a database or API) must be read. Memcached is free and open-source software, licensed under the Revised BSD license.〔 Memcached runs on Unix-like operating systems (at least Linux and OS X) and on Microsoft Windows. It depends on the libevent library. Memcached's APIs provide a very large hash table distributed across multiple machines. When the table is full, subsequent inserts cause older data to be purged in least recently used (LRU) order. Applications using Memcached typically layer requests and additions into RAM before falling back on a slower backing store, such as a database. The size of this hash table is often very large. It is limited to available memory across all the servers in the cluster of servers in a data centre. Where high volume, wide audience web publishing requires it, this may stretch to many gigabytes. Memcached can be equally valuable for situations where either the number of requests for content is high, or the cost of generating a particular piece of content is high. Memcached was originally developed by (Danga Interactive ) for LiveJournal, but is now used by many other systems, including MocoSpace,〔(MocoSpace Architecture - 3 Billion Mobile Page Views a Month ). High Scalability (2010-05-03). Retrieved on 2013-09-18.〕 YouTube, Reddit,〔(Steve Huffman on Lessons Learned at Reddit )〕 Survata,〔()〕 Zynga,〔(How Zynga Survived FarmVille )〕 Facebook,〔(Facebook Developers Resources )〕〔(Scaling Memcached at Facebook )〕〔(NSDI '13: Scaling Memcache at Facebook )〕 Orange,〔(Orange Developers )〕 Twitter,〔(It's Not Rocket Science, But It's Our Work )〕 Tumblr〔(Engineer – Core Applications Group job at Tumblr in New York, NY, powered by JobScore ). Jobscore.com. Retrieved on 2013-09-18.〕 and Wikipedia.〔(MediaWiki Memcached )〕 Engine Yard and Jelastic are using Memcached as part of their platform as a service technology stack〔(Engine Yard Technology Stack )〕〔(Jelastic Memcached System )〕 and Heroku offers several Memcached services〔(Heroku Memcached add-ons )〕 as part of their platform as a service. Google App Engine, AppScale, Microsoft Azure and Amazon Web Services also offer a Memcached service through an API.〔(Using Memcache - Google App Engine - Google Code )〕〔http://appscale.cs.ucsb.edu Memcached in AppScale〕〔(About In-Role Cache for Windows Azure Cache ). Msdn.microsoft.com. Retrieved on 2013-09-18.〕〔(Amazon ElastiCache ). Aws.amazon.com. Retrieved on 2013-09-18.〕 == History == Memcached was first developed by Brad Fitzpatrick for his website LiveJournal, on May 22, 2003.〔(changelog: livejournal ). Community.livejournal.com (2003-05-22). Retrieved on 2013-09-18.〕〔(brad's life - weather, running, distributed cache daemon ). Brad.livejournal.com (2003-05-22). Retrieved on 2013-09-18.〕〔(lj_dev: memcached ). Community.livejournal.com (2003-05-27). Retrieved on 2013-09-18.〕 It was originally written in Perl, then later rewritten in C by Anatoly Vorobey, then employed by LiveJournal.〔(lj_dev: memcached ). Lj-dev.livejournal.com (2003-05-27). Retrieved on 2013-09-18.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Memcached」の詳細全文を読む スポンサード リンク
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