Robust Transaction Routing in Distributed Database Systems

Abstract

In this paper, we examine the issue of robust transaction routing in distributed database systems. A class of dynamic routing strategies which use estimated response times to make routing decisions is studied in details. Since response time estimation and decision making depend on the assumed transaction model and parameters, it is important to examine the robustness or sensitivity to the inaccuracy in the assumptions and parameter values. Through simulations, we find that the dynamic routing strategy based strictly on response time is too aggressive in sharing loads and makes too many non-preferred system routings. It is robust with respect to change in the number of database calls per transaction, but is relatively sensitive to the distribution of database calls. Two refinements are proposed which improve system performance as well as robustness of routing decisions.