Catalog management in heterogeneous distributed database systems

In heterogeneous distributed database systems (HDDBSs), efficient handling of the global catalog is of great practical importance with respect to site autonomy, query optimization, authorization mechanism, and data distribution transparency. We propose a new catalog allocation scheme, named GOCAS (group-oriented catalog allocation scheme). GOCAS can reduce the number of inter-site messages for accessing catalog information by exploiting the locality of references that span a number of sites. This approach is contrary to the previous catalog allocation schemes, where the locality of references cannot be employed or can be applied restrictively to only one site. We also present the implementation details of GOCAS on our prototypical HDDBS, named DIME.