Persistent Logical Synchrony

The virtually synchronous execution model provides an appropriate support for developing reliable applications when the crash failure model is being assumed. Using it, group broadcasts only need to be based on asynchronous communication. Synchronization points are set when a view change arises, guaranteeing an efficient execution of such reliable applications. But a crash failure model is not always appropriate for all applications. Indeed, those using persistent or large state, like replicated databases, need a recoverable model. In such cases, the virtual synchrony property needs to be partially extended for adequately supporting more intricate recovery protocols. Persistent logical synchrony is one variation of this kind, that extends the synchronization actions to be taken when a view change arises, allowing a good support for partial recovery when the primary component membership is being assumed.