Paris Descartes University Seminar Series on Data Analytics
in collaboration with the diNo group

Invited Seminar Talk

Just-Right Consistency
Dr. Marc Shapiro, Inria Paris & LIP6-UPMC-Sorbonne Universities (France)

when: 21 November 2016, 3pm
where: room Turing Reunion, 7th floor, Paris Descartes University, 45 Rue Des Saints Peres, Paris 75006


Consistency ---ensuring that items of data distributed over remote computers agree with each other--- is a fundamental issue of distributed computing. No single consistency model is appropriate for all uses: strong consistency requires lots of synchronisation, which has availability and performance issues; weak consistency performs and scales better but is error-prone. Indeed, the famous "CAP" impossibility result shows there is an inherent trade-off between fault tolerance, performance, and programmability. The first part of the talk will provide some general background on the consistency trade-off. This has led to a split between databases designed for strong consistency and those designed for performance and availability; application designers must make an early decision of which consistency model to go with. Instead, we propose to fine-tune the database to provide the highest possible performance and availability that is appropriate for a given application. Our Just-Right Consistency approach leverages a novel static analysis (called CISE), which can prove whether a given distributed application maintains a given correctness invariant. In the second part of the talk, we will explain the intuition behind CISE, and how we use it to co-design the application and its consistency model, thereby minimising synchronisation to what is strictly necessary to ensure correctness.

Short Bio

Marc Shapiro does his research on distributed computer systems, data replication and consistency algorithms, and distributed garbage collection. He invented the proxy concept, which is now universal on the Internet. He published at SOSP and OSDI, the two most prestigious venues of the area. He was instrumental in the creation of EuroSys, the main European venue in the area. He authored 86 international publications, 18 recognised software systems, and five patents. Dr Shapiro's research started with a PhD from Universitéaul Sabatier for research performed at at LAAS in Toulouse, France (1980), followed by a post-doc at MIT, and a researcher position at CMIRH. He is a researcher at INRIA since 1984. He spent a one-year sabbatical at Cornell (1993.1994), and he led the Cambridge Distributed Systems group at Microsoft Research Cambridge (UK) from 1999 to 2005. He is currently a Senior Researcher for INRIA Paris, in the Regal group, located at LIP6. Dr. Shapiro, a Senior Member of the ACM, is known for his dedication to organising the Informatics community and making its voice heard in Europe. He has been a member of several Program Commitees in operating systems, distributed systems, persistent systems, and garbage collection.

Hosted by: Themis Palpanas

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