Cassandra is a simple, distributed database management system for large structured databases (so-called " NoSQL " database system ). It is designed for high scalability and reliability for large distributed systems. The data are stored in key-value ratios. It is open documented and implemented in Java. The implementation is distributed as free software under the terms of version 2 of the Apache license.
It was originally on Facebook by Avinash Lakshman ( one of the authors of Amazon's Dynamo ) and Prashant Malik developed for the Inbox Search problem with Facebook and released in July 2008. After that, other large companies such as IBM, Rackspace and Twitter have contributed to the code. The project was started in March 2009 Foundation of the Apache Software as a sub- project within the Apache Incubator. On February 17, 2010 Cassandra was declared by the Apache Software Foundation for " top-level " project and is therefore not a sub-project of Apache Incubator more. The published 2 June 2011 Version 0.8 introduces the Cassandra Query Language ( CQL ), a query language with SQL - like syntax.
Cassandra is being used on Twitter, Digg and Reddit. Post to Facebook it operated until mid-2011 hundreds of millions of members ( Since July 2011, replaced by a combination of HBase, HDFS and Haystack ).
DataStax lists a large number (160 in March 2012 ) of users of its website. The filters offered for a better overview by market segments to emphasize the wide range of applications: etc. Communication, Education, Financial, Healthcare, Security, Social Media / Networks. Cassandra is the most popular column-oriented NoSQL database.
Cassandra is a column-oriented NoSQL database. It can be seen as a mixture of Amazon Dynamo and Google 's BigTable, as it can easily develop the replication mechanisms of Dynamo uses, but at the same time provides the data structure of BigTable outward.