PARTITIONED DATA OBJECTS IN DISTRIBUTED DATABASES

In many distributed databases ''locality of reference'' is crucial to achieve acceptable performance. However, the purpose of data distribut ion is to spread the data among several remote sites. One way to solve this contradiction is to use partitioned data techniques. instead of accessing the entire data, a site works on a fraction that is made loc ally available, thereby increasing the site's autonomy. We present a t heory of partitioned data that formalizes the concept and establishes the basis to develop a correctness criterion and a concurrency control protocol for partitioned databases. Set-serializability is proposed a s a correctness criterion and we suggest an implementation that integr ates partitioned and non-partitioned data. To complete this study, the policies required in a real implementation are also analyzed.