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Sobre

Em termos de temas de investigação principais destaca-se a gestão de dados em modelos de coerência fraca, mecanismos de agregação de dados e causalidade em sistemas distribuídos. No últimos anos, e em colaboração outros investigadores, têm sido desenvolvidos mecanismos de sumarização de dados como os Scalable Bloom Filters, registo de causalidade em ambientes dinâmicos com Interval Tree Clocks e Dotted Version Vectors, bem como abordagens robustas para o suporte à alta disponibilidade com coerência fraca via Conflict-Free Replicated Data Types. Alguns destes mecanismos têm sido aplicados na base de dados distribuída Riak e no Akka distributed data, estando estes mesmos em uso em diversas aplicações finais com milhões de utilizadores a nível global.

Tópicos
de interesse
Detalhes

Detalhes

  • Nome

    Carlos Baquero
  • Cluster

    Informática
  • Cargo

    Responsável de Área
  • Desde

    01 novembro 2011
003
Publicações

2019

Scalable eventually consistent counters over unreliable networks

Autores
Almeida, PS; Baquero, C;

Publicação
Distributed Computing

Abstract

2019

Conflict-Free Replicated Data Types CRDTs

Autores
Preguiça, NM; Baquero, C; Shapiro, M;

Publicação
Encyclopedia of Big Data Technologies.

Abstract

2019

Efficient synchronization of state-based CRDTs

Autores
Enes, V; Almeida, PS; Baquero, C; Leitao, J;

Publicação
Proceedings - International Conference on Data Engineering

Abstract
To ensure high availability in large scale distributed systems, Conflict-free Replicated Data Types (CRDTs) relax consistency by allowing immediate query and update operations at the local replica, with no need for remote synchronization. State-based CRDTs synchronize replicas by periodically sending their full state to other replicas, which can become extremely costly as the CRDT state grows. Delta-based CRDTs address this problem by producing small incremental states (deltas) to be used in synchronization instead of the full state. However, current synchronization algorithms for delta-based CRDTs induce redundant wasteful delta propagation, performing worse than expected, and surprisingly, no better than state-based. In this paper we: 1) identify two sources of inefficiency in current synchronization algorithms for delta-based CRDTs; 2) bring the concept of join decomposition to state-based CRDTs; 3) exploit join decompositions to obtain optimal deltas and 4) improve the efficiency of synchronization algorithms; and finally, 5) experimentally evaluate the improved algorithms. © 2019 IEEE.

2019

Efficient Synchronization of State-based CRDTs

Autores
Enes, V; Almeida, PS; Baquero, C; Leitao, J;

Publicação
2019 IEEE 35TH INTERNATIONAL CONFERENCE ON DATA ENGINEERING (ICDE 2019)

Abstract
To ensure high availability in large scale distributed systems, Conflict-free Replicated Data Types (CRDTs) relax consistency by allowing immediate query and update operations at the local replica, with no need for remote synchronization. State-based CRDTs synchronize replicas by periodically sending their full state to other replicas, which can become extremely costly as the CRDT state grows. Delta-based CRDTs address this problem by producing small incremental states (deltas) to be used in synchronization instead of the full state. However, current synchronization algorithms for delta-based CRDTs induce redundant wasteful delta propagation, performing worse than expected, and surprisingly, no better than state-based. In this paper we: 1) identify two sources of inefficiency in current synchronization algorithms for delta-based CRDTs; 2) bring the concept of join decomposition to state-based CRDTs; 3) exploit join decompositions to obtain optimal deltas and 4) improve the efficiency of synchronization algorithms; and finally, 5) experimentally evaluate the improved algorithms.

2019

Higher-order patterns in replicated data types

Autores
Leijnse, A; Almeida, PS; Baquero, C;

Publicação
Proceedings of the 6th Workshop on Principles and Practice of Consistency for Distributed Data, PaPoC 2019

Abstract
The design of Conflict-free Replicated Data Types traditionally requires implementing new designs from scratch to meet a desired behavior. Although there are composition rules that can guide the process, there has not been a lot of work explaining how existing data types relate to each other, nor work that factors out common patterns. To bring clarity to the field we explain underlying patterns that are common to flags, sets, and registers. The identified patterns are succinct and composable, which gives them the power to explain both current designs and open up the space for new ones. © 2019 Copyright held by the owner/author(s). Publication rights licensed to ACM.

Teses
supervisionadas

2017

Broadcast Cancellation in Unstructured Networks

Autor
Rui Manuel Dias Ferreira Lima

Instituição
UM

2017

Efficient Synchronization of state-based CRDTs

Autor

Instituição
UM

2017

Sensing, coordination and actuation in office spaces

Autor

Instituição
UM

2016

Optimizing Operation-based Conflict-free Replicated Data Types

Autor
Georges Younes

Instituição
UM

2016

Broadcast Cancellation

Autor
Rui Manuel Dias Ferreira Lima

Instituição
UM