Past Meetup

PWL #18: Conflict-Free Replicated Data Types

This Meetup is past

43 people went


1301 5th Avenue #1600 · Seattle, WA

How to find us

Your best bet is to enter through the doors on 4th Ave and work your way southeast to the elevators. #1600 is on the 16th floor.

Location image of event venue


Y'all have called my bluff, we're talking about CRDTs! We'll use "A comprehensive study of Convergent and Commutative Replicated Data Types."

Eventual consistency aims to ensure that replicas of some mutable shared object converge without foreground synchronisation. Previous approaches to eventual consistency are ad-hoc and error-prone. We study a principled approach: to base the design of shared data types on some simple formal conditions that are sufficient to guarantee eventual consistency. We call these types Convergent or Commutative Replicated Data Types (CRDTs). This paper formalises asynchronous object replication, either state based or operation based, and provides a sufficient condition appropriate for each case. It describes several useful CRDTs, including container data types supporting both add and remove operations with clean semantics, and more complex types such as graphs, montonic DAGs, and sequences. It discusses some properties needed to implement non-trivial CRDTs.