Concurrency control for global transaction management in mdbss

Abstract

The objectives of global transaction management in mul-tidatabase systems(MDBS) are to avoid the inconsistent retrievals and guarantee the global serializability under the existence of indirect conflict which is unknown to to the global transaction manager(GTM). Many researches have shown that it is difficult to design the global concurrency control method because of local autonomy. In these method global transactions have a few opportunities to be executed concurrently. We concentrate our attention on 1) investigation into the more accurate indirect conflict situation and 2) supporting the higher concurrency degree by using the concept of global integrity constraints. We define the mul-tidatabase transaction model and then propose the concurrency control protocols. In our method the more global transaction can be concurrently executed, since the refined boundary of possibility of indirect conflict is offered.