Università della Svizzera italiana

P-Store : genuine partial replication in wide area networks

Schiper, Nicolas ; Sutra, Pierre ; Pedone, Fernando

Partial replication is a way to increase the scalability of replicated systems since updates only need to be applied to a subset of the system’s sites, thus allowing replicas to handle independent parts of the workload in parallel. In this paper, we propose P-Store, a partial database replication protocol for wide area networks. In P-Store, each transaction T optimistically executes on one...

Università della Svizzera italiana

High-performance transaction processing in sprint

Camargos, Lásaro ; Pedone, Fernando ; Wielochy, Marcin

Sprint is a middleware infrastructure for high performance and high availability data management. It extends the functionality of a standalone in-memory database (IMDB) server to a cluster of commodity shared-nothing servers. Applications accessing an IMDB are typically limited by the memory capacity of the machine running the IMDB. Sprint partitions and replicates the database into segments...

Università della Svizzera italiana

Fast, flexible, and highly resilient genuine fifo and causal multicast algorithms

Schiper, Nicolas ; Pedone, Fernando

We study the fifo and causal multicast problem, two group-communication abstractions that deliver messages in an order consistent with their context. With fifo multicast, the context of a message m at a process p is all messages that were previously multicast by m’s sender and addressed to p. Causal multicast extends the notion of context to all messages that are causally linked to m by a...

Università della Svizzera italiana

Genuine versus non-genuine atomic multicast protocols

Schiper, Nicolas ; Sutra, Pierre ; Pedone, Fernando

In this paper, we study atomic multicast, a fundamental abstraction for building fault-tolerant systems. We suppose a system composed of data centers, or groups, that host many processes connected through high-end local links; a few groups exist, interconnected through high-latency communication links. In this context, a recent paper has shown that no multicast protocol can deliver messages...

Università della Svizzera italiana

Optimistic algorithms for partial database replication

Schiper, Nicolas ; Schmidt, Rodrigo ; Pedone, Fernando

In this paper, we study the problem of partial database replication. Numerous previous works have investigated database replication, however, most of them focus on full replication. We are here interested in genuine partial replication protocols, which require replicas to permanently store only information about data items they replicate. We define two properties to characterize partial...

Università della Svizzera italiana

Conflict-aware load-balancing techniques for database replication

Zuikeviciute, Vaide ; Pedone, Fernando

Middleware-based database replication protocols require few or no changes in the database engine. As a consequence, they are more portable and flexible than kernel-based protocols, but have coarser-grain information about transaction access data, resulting in reduced concurrency and increased aborts. This paper proposes conflict-aware load-balancing techniques to increase the concurrency and...

Università della Svizzera italiana

A highly available log service for distributed transaction processing

Camargos, Lásaro ; Wieloch, Marcin ; Pedone, Fernando

Processing distributed transactions hinges on enforcing atomicity and durability: resource managers participating in a transaction must agree on its outcome and the transaction updates must be permanent. We introduce the log service abstraction, which gathers resource managers’ votes to commit or abort a transaction and their updates, and outputs the transaction’s outcome. Updates are made...

Università della Svizzera italiana

Multicoordinated paxos

Camargos, Lásaro ; Schmidt, Rodrigo ; Pedone, Fernando

Classic Paxos is a round-based distributed consensus algorithm. Normally, proposals are sent to the round leader and decided in two communication steps more. Fast Paxos extends Classic Paxos by allowing also fast rounds, in which a decision can be learned in two communication steps without relying on a leader but requiring bigger quorums. We extend Fast Paxos and allow yet another sort of round...

Università della Svizzera italiana

Solving atomic multicast when groups crash

Schiper, Nicolas ; Pedone, Fernando

In this paper, we study the atomic multicast problem, a fundamental abstraction for building faulttolerant systems. In the atomic multicast problem, the system is divided into non-empty and disjoint groups of processes. Multicast messages may be addressed to any subset of groups, each message possibly being multicast to a different subset. Several papers previously studied this problem either in...

Università della Svizzera italiana

Correctness criteria for database replication : theoretical and practical aspects

Zuikeviciute, Vaide ; Pedone, Fernando

In this paper we investigate correctness criteria for replicated databases from the client's perspective and present their uniform characterization. We further study the effects of different consistency degrees in the context of three middleware-based replication protocols: primarybackup, optimistic update-everywhere and BaseCON, a simple yet faulttolerant middleware-based replication protocol...