Keep CALM and CRDT On
Abstract
Despite decades of research and practical experience, developers have few tools for programming reliable distributed applications without resorting to expensive coordination techniques. Conflict-free replicated datatypes (CRDTs) are a promising line of work that enable coordination-free replication and offer certain eventual consistency guarantees in a relatively simple object-oriented API. Yet CRDT guarantees extend only to data updates; observations of CRDT state are unconstrained and unsafe. We propose an agenda that embraces the simplicity of CRDTs, but provides richer, more uniform guarantees. We extend CRDTs with a query model that reasons about which queries are safe without coordination by applying monotonicity results from the CALM Theorem, and lay out a larger agenda for developing CRDT data stores that let developers safely and efficiently interact with replicated application state.
Cite
@article{arxiv.2210.12605,
title = {Keep CALM and CRDT On},
author = {Shadaj Laddad and Conor Power and Mae Milano and Alvin Cheung and Natacha Crooks and Joseph M. Hellerstein},
journal= {arXiv preprint arXiv:2210.12605},
year = {2022}
}