Applied Monotonicity: A Brief History of CRDTs in Riak

Basho had a collaboration with the researchers in the SyncFree Consortium, authors of the original CRDT work and actively researching new CRDT designs and their applicability in industry use cases presented by both Rovio Entertainment (creator of Angry Birds, participant in the SyncFree Consortium) and Riot Games (creator of League of Legends, long time Riak user.) Inspired by previous work (Bieniusa et al. 2012) on optimizing CRDT set representations for operation-based CRDTs – Riak needed state-based CRDTs due to it’s lack of causal delivery and anti-entropy replica repair mechanism – Russell arrived at a design for an optimized set representation that was dubbed the Observed-Remove Set Without Tombstones. In modeling the Observed-Remove Set Without Tombstones we are going to use a pair consisting of a version vector – representing a compact version of the causal history of the object – and a payload set – containing the elements that should currently be in the set.

Source: christophermeiklejohn.com