Using Subpages for Coherency Control in Parallel Database Systems

. Implementing databases on distributed memory multicomputers raises the problem, how to implement a database cache which uses shared memory concepts extensively under such a hardware architecture. In this paper we describe a solution to this problem by introducing a virtual database cache (VDBC). The VDBC is an algorithmic approach based on the lazy release consistency model and on the transaction concept. Additionally, the VDBC uses pages subdivided into equal sized subpages to maintain concurrency and cache coherency and to reduce data contention on often accessed pages. Our approach is based on the assumption, that interprocessor communication is quite favorable as compared to I/O. A detailed version of the paper can be found in [5]. 1 Introduction Increasing requirements such as higher transaction rates or shorter response times make it attractive to parallelize existing relational database management systems (RDBMS) and to implement them on multiprocessors based on distributed m..