A CRDT library with δ-CRDT support.
Alexander Songe 21b2710b1b Merge pull request #4 from frmendes/master 2 years ago
config Initial commit. Minimal testing. Minimal docs 4 years ago
lib Add tests for LWWRegister join 2 years ago
test Add missing LWWRegister join assertion 2 years ago
.gitignore Updating docs and deps 4 years ago
.travis.yml New API for deltas, etc 4 years ago
LICENSE Preparing a preview release... 4 years ago
README.md Updating docs and deps 4 years ago
coveralls.json A bit more test coverage 4 years ago
mix.exs Updating docs and deps 4 years ago
mix.lock Updating docs and deps 4 years ago



Build Status Coverage Status Docs Status Hex docs Current Release License Apache2

Loom is a set of basic CRDT's that are designed to be composable and extensible. We include support for delta-CRDT's (δ-CRDT's) where it makes sense.


In order to combat issues with large objects, δ-CRDT's are supported for some datatypes. You can extract deltas from delta-CRDT's, and periodically clear them out from your datastructures to reduce memory constraints.

What the heck is a CRDT?

Conflict-free, Coordination-free, Commutative, or Convergent datatypes, CRDT's are usually formally described as "join semi-lattices". Mathematical jargon aside, CRDT's track causality for modifications to your data. Because of this, time becomes less relevant, and coordination becomes unnecessary to get accurate values for your data.

Can you give me an example of one?

I will have a simple explanation here for a basic gcounter and a pncounter.

For now, I can simply point you to the GCounter code in here.

Where can I learn more?

  • Strong Eventual Consistency and Conflict-free Replicated Data Types
    • A good introduction to the concept of CRDTs: http://research.microsoft.com/apps/video/default.aspx?id=153540&r=1
  • A comprehensive study of Convergent and Commutative Replicated Data Types
    • A survey with references for several popular CRDTs: http://hal.inria.fr/docs/00/55/55/88/PDF/techreport.pdf
  • Efficient State-based CRDTs by Delta-Mutation
    • Talk: https://www.youtube.com/watch?v=y_ewFP-lgyM
    • Paper: http://arxiv.org/pdf/1410.2803v1.pdf