Maintaining cache coherency in a multisystem data sharing environment

Abstract

Abstract A multisystem data sharing environment (MDSE) refers to a distributed architecture for high performance transaction processing. In the MDSE, the computing nodes are locally coupled via a high-speed network and share a common database at the disk level. To reduce the amount of expensive and slow disk I/O, each node caches database pages in its main memory buffer. However, since a particular page may be simultaneously cached in different nodes, cache coherency should be maintained to ensure that the nodes always see the most recent version of database pages. In this paper, we propose two coherency control schemes for the MDSE. The proposed schemes improve the performance by alleviating the amount of message traffic or by reducing the number of cache misses. Using a distributed database simulation model, we evaluate the performance of the proposed schemes under a wide variety of database workloads. Our results indicate that the proposed schemes exhibit substantial performance improvement over the previous schemes when data contention is high or when transactions referencing similar data are clustered together to be executed on the same node.