Integrating Optimistic Virtual Synchrony to a CORBA Object Group Service Gláucia de Oliveira Dias and Alba Cristina Magalhaes Alves de Melo   View Paper (PDF)   Return to Dependability, Security, Assurance Abstract In dynamic object groups, objects are allowed to join or leave the group at any time during the group lifetime. Each time the number of members in a group changes, a new view is created. Virtual synchrony is an useful property in dynamic groups which guarantees that if two processes stay in the same view after a view change, the same set of messages will be delivered to them. Most of the protocols that implement virtual synchrony stop regular message activity while a view change is under way. Optimistic virtual synchrony (OVS) allows messages to be sent and received while a view is changing by estimating which members would be present in the next view. If the estimation is wrong, messages are "rolled back". In this paper, we propose and evaluate an approach to integrate OVS to a CORBA group service called OGS. Our results show that OVS provides very good performance improvements during view changes when compared with other protocols that guarantee virtual synchrony. DiSC'03 © 2003 Association for Computing Machinery