On Affinity Based Routing in Multi-System Data Sharing

Multiple systems coupling incurs performance degradation due to inter-system (global) lock conlention and database buffer invalidation. At high transaction rates, the level of inter-syslem interference can have a severe hnpact on performance. In this paper, we propose a scheme for transaction routing lhat reduces inter-system interference while keeping load nearly balanced. The routing decision is based on affinity relations defined between transactions and databases. A methodology, employing an integer linear programming technique, is developed to classify incoming transactions into affinity groups based on their dotuba& call reference puffem. Based on traces from two of IBM’s high volume single system customers, we find that. at high lransaction rates, the proposed aflinily based routing significantly reduces the lock contention probability and leads to a substantial reduction in transaction response time. Further, the reduction in inter-system data contenlion, produces a large hnpact on the performance of optimislic type concurrency control.