Organizations that collect large amounts of unstructured data are increasingly turningto non-relational databases, now frequently called NoSQL databases [4]. NoSQL databases
focus on analytical processing of large scale datasets, offering increased scalability over
commodity hardware [8]. Computational and storage requirements of applications such as forBig Data Analytics [9], Business Intelligence [10] and social networking over peta-byte
datasets have pushed SQL-like centralized databases to their limits [5]. This led to the
development of horizontally scalable, distributed non-relational data stores, called No-SQL
databases, such as Google's Bigtable [6] and its open-source implementation HBase [33] and
Facebook's Cassandra[7]. The emergence of distributed key-value stores, such as Cassandra
and Voldemort [44], proves the efficiency and cost effectiveness of their approaches [3]. Themain limitations with RDBMS are it is hard to scale with Data warehousing, Grid, Web 2.0
and Cloud applications [16]. Pokorny, J. (2011), focuses on NoSQL databases in context of
cloud computing, particularly their horizontal scalability and concurrency model [17].
NoSQL databases are differing from Relational Database Management Systems (RDBMS)
But NoSQL databases did not guarantee ACID properties [19].