Recovery and performance balance of a COTS DBMS in the presence of operator faults

A major cause of failures in large database management systems (DBMS) is operator faults. Although most of the complex DBMS have comprehensive recovery mechanisms, the effectiveness of these mechanisms is difficult to characterize. On the other hand, the tuning of a large database is very complex and database administrators tend to concentrate on performance tuning and disregard the recovery mechanisms. Above all, database administrators seldom have feedback on how good a given configuration is concerning recovery. This paper proposes an experimental approach to characterize both the performance and the recoverability in DBMS. Our approach is presented through a concrete example of benchmarking the performance and recovery of an Oracle DBMS running the standard TPC-C benchmark, extended to include two new elements: a fault load based on operator faults and measures related to recoverability. A classification of operator faults in DBMS is proposed. The paper ends with the discussion of the results and the proposal of guidelines to help database administrators in finding the balance between performance and recovery tuning.