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Data replication serves to improve the availability and performance of distributed systems. The price to be paid consists of costs caused by protocols by which a sufficient degree of consistency of replicated data is maintained. Different kinds of targeted applications require different kinds of replication protocols, each one requiring a different set of(More)
Database replication protocols need to detect, block or abort part of conflicting transactions. A possible solution is to check their writesets (and also their readsets in case a serialisable isolation level is requested), which however burdens the consumption of CPU time. This gets even worse when the replication support is provided by a middleware, since(More)
Logic links philosophy with computer science and is the acknowledged foundation of information systems. Since the large scale proliferation of the internet and the world wide web, however, a rush of new technologies is avalanching, in many cases without much consideration of a solid foundation that would be up to par with the rigor of the traditional logic(More)
Integrity maintenance methods have been defined for preventing updates from violating integrity constraints. Depending on the update, the full check for constraint satisfaction is reduced to checking certain instances of some relevant constraints only. In the first part of the paper new ideas are proposed for enhancing the efficiency of such a method. The(More)
Replication protocols using an eager update propagation strategy commonly need a reliable broadcast service; i.e., a broadcast primitive with atomic delivery and, in some cases, also with total order. This communication service provides some appropriate features for the recovery tasks, although in some cases this leads to partial blocking of the replica(More)