There has been a great deal of hype about cloud computing. Cloud computing
promises inﬁnite scalability and high availability at low cost. Currently, Amazon
Web Services is the most popular suite of cloud computing services, but other ven-
dors such as Adobe, Google, and Microsoft are also appearing on the market place.
The purpose of this paper is to demonstrate the opportunities and limitations of us-
ing cloud computing as an infrastructure for general-purpose Web-based database
applications. The paper studies alternative consistency protocols in order to build
database services on top cloud storage services. Furthermore, the paper studies al-
ternative client-server and indexing architectures. Both the performance (response
time) and cost trade-offs are studied.