A multidatabase transaction model for InterBase

The management of multidatabase transactions presents new and interesting challenges, due mainly to the requirement of the autonomy of local database systems.In this paper, we present an extended transaction model which provides the following features useful in a multidatabase environment:(1) It allows the composition of flexi.bletransactions which can tolerate failures of individual sub transactions by taking advantage of the fact that a given function can frequently be accomplished by more than one database system; (2) It supports the concept of mixed transactions allowing compensatable and non-compensatable subtransactions to coexist within a single global transaction; and (3) It incorporates the concept of time jn both the subtransaction and global transaction processing, thus allowing more flexibility in transaction scheduling.We formally define the extended transaction model and discuss its transaction scheduling mechanism.