1. Introduction
In recent years, database outsourcing has become an important component of cloud
computing. Due to the rapid advancements in a network technology, the cost of
transmitting a terabyte of data over long distances has decreased significantly in the past
decade. In addition, the total cost of data management is five to ten times higher than the
initial acquisition cost. As a result, there is a growing interest in outsourcing database
management tasks to third parties that can provide these tasks for much lower cost due to
the economy of scale. This new outsourcing model has the benefits of reducing the cost
for running Database Management System (DBMS) independently [1]. Cloud computing
economics leveraging the power of multi-tenancy delivers extremely fast shared storage at
a dramatically reduced cost. Virtualization then compounds these advantages by enabling
users to scale elastically and to pay only for the resources they use. The cost/performance
advantages have decisively shifted in favor of the shared-disk DBMS. It is just a matter of
time before the shared-disk DBMS establishes dominance in the cloud.
A Cloud database management system (CDBMS) is a distributed database that delivers
computing as a service instead of a product. It is the sharing of resources, software, and
information between multiply devices over a network which is mostly the internet. It is
expected that this number will grow significantly in the future. An example of this is
Software as a Service, or SaaS, which is an application that is delivered through the
browser to customers. Cloud applications connect to a database that is being run on the
cloud and have varying degrees of efficiency. Some are manually configured, some are
preconfigured, and some are native. Native cloud databases are traditionally better
equipped and more stable that those that are modified to adapt to the cloud