Achieving robustness in distributed database systems
Derek L. Eager, Kenneth C. Sevcik · ACM Transactions on Database Systems · 1983
The problem of concurrency control in distributed database systems in which site and communication link failures may occur is considered. The possible range of failures is not restricted; in particular, failures may induce an arbitrary network partitioning. It is desirable to attain a high “level of robustness” in such a system; that is, these failures should have only a small impact on system operation. A level of robustness termed maximal partial operability is identified. Under our models of concurrency control and robustness, this robustness level is the highest level attainable without significantly degrading performance. A basis for the implementation of maximal partial operability is presented. To illustrate its use, it is applied to a distributed locking concurrency control method and to a method that utilizes timestamps. When no failures are present, the robustness modifications for these methods induce no significant additional overhead.