2022-05210 - R&D Engineer
Le descriptif de l’offre ci-dessous est en Anglais

Contrat renouvelable : Oui

Niveau de diplôme exigé : Bac + 5 ou équivalent

Fonction : Ingénieur scientifique contractuel

Niveau d'expérience souhaité : De 3 à 5 ans

Contexte et atouts du poste

In a cloud-edge environment a multi-synchronous access of data on edge devices needs to be ensured. This multi-synchronous access includes an asynchronous mode where the user can always access the data on the device even when the device is off-line, and a synchronous mode where as long as the device is online the data on the device is kept synchronous with the data stored in the cloud.

We proposed augmenting existing relational database schema with a Conflict-free Replicated Relations (CRRs) layer in order to support a multi-synchronous access to relational databases in a cloud-edge environment [1]. The underlying CRR layer uses CRDTs to allow immediate data access at edge and to guarantee data convergence when the edge devices are online. It also resolves violations of integrity constraints at merge by undoing offending updates. Since a relation instance is a set of tuples, the basic building block of CRR is a set CRDT, more specifically a delta-state set CRDT.

The key issue that a general-purpose set CRDT must address is how to identify the causality between the different insertion and deletion updates. CLSet, our novel set CRDT suitable for relational databases identifies causality relations by using the abstraction of causal length, which is based on two observations. First, the insertions and deletions of a given element occur in turns, one causally dependent on the other. A deletion is an inverse of the last insertion it sees. Similarly, an insertion is an inverse of the last deletion it sees (or none, if the element has never been inserted). Second, two concurrent executions of the same mutation of a set CRDT fulfill the same purpose and therefore are regarded as the same update. Seeing one means seeing both. Two concurrent inverses of the same update are also regarded as the same one.

[1] Weihai Yu and Claudia-Lavinia Ignat. Oct. 2020. “Conflict-Free Replicated Relations for Multi-Synchronous Database Management at Edge”. In: The IEEE International Conference on Smart Data Services (SMDS 2020). Beijing, China.

Mission confiée

The recruted engineer will be in charge of the implementation of a CRR prototype and experimentation of the performances of this prototype.

Principales activités

  1. Study of the CRDT solution proposed in [1]
  2. Implementation of the prototype proposed in [1] in SQLite by following the development best practices (version control management, tests, continuous integration, documentation)
  3. Study and proposal of a solution for maintenance of integrity constraints
  4. Experimentation by means of simulations for testing the performances of the proposed solution


Master or equivalent in Computer science is required.

Required theoretical expertise: distributed systems

Required technical expertise: object-oriented or functional programming languages, web technology


  • Subsidized meals
  • Partial reimbursement of public transport costs
  • Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
  • Possibility of teleworking (after 6 months of employment) and flexible organization of working hours
  • Professional equipment available (videoconferencing, loan of computer equipment, etc.)
  • Social, cultural and sports events and activities
  • Access to vocational training
  • Social security coverage


The remuneration will be determined according to the years of experience:

from 2562,00€ to 3240,00€ gross monthly.