Memcached is a cache server released under the BSD license for the general deposit and retrieval of data from memory. The software is mainly used for websites that temporarily store data from database systems on the server. It is used to improve performance for many dynamic websites with database connectivity by eliminating the need for disk accesses or minimizing the invocation of time-consuming and frequently used database queries - especially SELECT statements - by keeping important data in memory.
History:
Memcached was originally developed by the company Danga Interactive for the Internet portal LiveJournal. Until June 15, 2003 the software was under the GPL, when the licensing was changed to the BSD license. In the meantime, the use of the software is widespread and is used, for example, by Facebook and Wikipedia alone to serve billions of users per month.
Functionality:
The connection to such a server takes place via the TCP and IP protocols. Data is assigned a unique key value (comparable to the name of a variable) and stored as character strings in the working memory. In order to enable the storage of data types such as integer or floating point numbers as well as objects, these data are serialized in advance by most program libraries.
Data can be stored either permanently or temporarily. For the latter case, memcached handles the deletion automatically.