A note on performance of VM/370 in the integration of models and databases

Prepared in association with the Alfred P. Sloan School of ManagementAs the proliferation of programming systems and database systems continues and, correspondingly, as the need for integrating these systems for certain applications increases, VM/370 offers a mechanism for such integration. This paper analyzes the performance of a configuration of virtual machines using VM/370 that allows for the sharing of a database system among several incompatible programs in an interactive environment. Specifically, two aspects of performance are addressed--an experimental study of the overhead cost incurred in the interface mechanisms employed, and a theoretical study of the degradation of response time due to the locking mechanisms employed. The conclusion of the experimental observations is that for sophisticated, complex accesses to the database system, the overhead costs are relatively small. The result of the theoretical study is the quantification of that degradation as a function of speeds of the database machine and the rate with which queries are made. The discussion of the practical implications of this theoretical study presents ways to improve this degradation. The observed conclusion of this work is our feeling that, for certain application areas, the benefits resulting from increased effectiveness of users outweigh the costs incurred