Discuss the costs that need to be considered in distributed query optimization and discuss two different cost models. Describe the distributed query optimization algorithms used by R* and SDD-1....

Discuss the costs that need to be considered in distributed query optimization and discuss two different cost models. Describe the distributed query optimization algorithms used by R* and SDD-1. Briefly describe the distributed functionality of Oracle9i. Produce the local wait-for graphs (WFGs) for each of the sites. What can you conclude from the local WFGs? Using the above transactions, demonstrate how Obermarck’s method for distributed deadlock detection works. What can you conclude from the global WFG?