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About

About

My research interests cover data management in eventual consistent settings, distributed data aggregation and causality tracking. In the last years I have collaborated with my co-authors in the development of data summary mechanisms such as Scalable Bloom Filters, causality tracking for dynamic settings with Interval Tree Clocks and Dotted Version Vectors and in predictable eventual consistency with Conflict-Free Replicated Data Types. My recent work has been applied in the Riak distributed database and in Akka distributed data, and is running in production systems serving millions of users worldwide.

Interest
Topics
Details

Details

  • Name

    Carlos Baquero
  • Cluster

    Computer Science
  • Role

    Area Manager
  • Since

    01st November 2011
003
Publications

2019

Scalable eventually consistent counters over unreliable networks

Authors
Almeida, PS; Baquero, C;

Publication
Distributed Computing

Abstract

2019

Conflict-Free Replicated Data Types CRDTs

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

Publication
Encyclopedia of Big Data Technologies.

Abstract

2019

Efficient synchronization of state-based CRDTs

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

Publication
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.

2018

Delta State Replicated Data Types

Authors
Almeida, PS; Shoker, A; Baquero, C;

Publication
JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING

Abstract

2018

Global-Local View: Scalable Consistency for Concurrent Data Types

Authors
Akkoorath, DD; Brandão, J; Bieniusa, A; Baquero, C;

Publication
Euro-Par 2018: Parallel Processing - 24th International Conference on Parallel and Distributed Computing, Turin, Italy, August 27-31, 2018, Proceedings

Abstract
Concurrent linearizable access to shared objects can be prohibitively expensive in a high contention workload. Many applications apply ad-hoc techniques to eliminate the need for synchronous atomic updates, which may result in non-linearizable implementations. We propose a new model which leverages such patterns for concurrent access to objects in a shared memory system. In this model, each thread maintains different views on the shared object: a thread-local view and a global view. As the thread-local view is not shared, it can be updated without incurring synchronization costs. These local updates become visible to other threads only after the thread-local view is merged with the global view. This enables better performance at the expense of linearizability. We discuss the design of several datatypes and evaluate their performance and scalability compared to linearizable implementations. © 2018, Springer International Publishing AG, part of Springer Nature.

Supervised
thesis

2017

Broadcast Cancellation in Unstructured Networks

Author
Rui Manuel Dias Ferreira Lima

Institution
UM

2017

Efficient Synchronization of state-based CRDTs

Author

Institution
UM

2017

Sensing, coordination and actuation in office spaces

Author

Institution
UM

2016

0

Author
Rosária Maria Afonso Rodrigues de Melo

Institution
UP-FCNA

2016

Optimizing Operation-based Conflict-free Replicated Data Types

Author
Georges Younes

Institution
UM