Technical Report TRCS00-01 Database Replication Using Epidemic Update

Due to severe performance penalties associated with synchronous replication, there is an increasing interest in asynchronous replica management protocols in which database transactions are executed locally, and the effects of these transactions are incorporated asynchronously on remote database copies. However, the asynchronous protocols currently in use either do not guarantee consistency and serializability as needed by transactional semantics or they impose restrictions on placement of data and on which data objects can be updated. In this paper we investigate an epidemic update protocol that guarantees consistency and serializability in spite of a write-anywhere capability. We conducted experiments on a detailed simulation of a distributed, replicated database to evaluate this protocol. Our results establish that this epidemic approach is indeed a viable alternative to traditional eager update protocols for a distributed database environment where consistency and full serializability are needed.