A framework to reason about consistency and atomicity guarantees in a sparsely-connected, partially-replicated peer-to-peer system

TL;DR

This paper introduces models and guidelines for ensuring consistency and atomicity in offline-first, sparsely-connected peer-to-peer systems with partial data replication.

Contribution

It presents extsc{IntersectionAtomicity} and extsc{IntersectionCC} models to reason about consistency and atomicity in such systems, aiding developers in design.

Findings

Models help reason about consistency in sparse, partially-replicated systems

Guidelines assist developers in designing for atomicity and consistency

Addresses challenges of offline, mesh network environments

Abstract

For an offline-first collaborative application to operate in true peer-to-peer fashion, its collaborative features must function even in environments where internet connectivity is limited or unavailable. Each peer may only be interested in a subset of the application data relevant to its workload, and this subset can overlap in different ways with those of other peers. Limitations imposed by access control and mesh network technologies often result in peers being sparsely connected. Reasoning about consistency in these systems is hard, especially when considering transactional updates that may alter different sets of data in the same transaction. We present \textsc{IntersectionAtomicity} and \textsc{IntersectionCC} as models to reason about offline-first collaborative applications that are sparsely-connected and rely on partially replicating different subsets of a broader set of data. We then use these models to propose a set of guidelines to help developers design their application with atomicity and consistency guarantees.