Relaxation Based SaaS for Repairing Failed Queries over the Cloud Computing

Cloud Computing based Software as a Service (SaaS) combines multiple Web Services to satisfy a SaaS request, therefore SaaS should be able to dynamically seek replacements for faulty or underperforming services, thus performing self-healing. However, it may be the case of available services that do not match all user's request, leading the system to grind to a halt. It is better to have an alternative candidate in the cloud while not fullfilling all the constraints. In this paper, we provide a Relaxation SaaS solution to repair the failed user's query by rewriting it with an approximation. It is based on an incremental approach that exploits Quantified Satisfiability (QSAT) problem to repair the query and provide an alternative SaaS that leads to a successful request closed to the original one with maximized Quality of Service (QoS).