Correct Answer : July 2008
Explanation :
Avinash Lakshman, one of the authors of Amazon's Dynamo, and Prashant Malik initially developed Cassandra at Facebook to power the Facebook inbox search feature. Facebook released Cassandra as an open-source project on Google code in July 2008. In March 2009 it became an Apache Incubator project. On February 17, 2010 it graduated to a top-level project.
Facebook developers named their database after the Trojan mythological prophet Cassandra, with classical allusions to a curse on an oracle.
