Concurrency Control and Awareness Support for Multi-synchronous Collaborative Editing

International audienceCollaborative editing tools have become increasingly popular in the last decade, with some systems being used by massive numbers of users. While traditionally collaborative editing systems would either target synchronous or asynchronous collaboration settings, some recent systems support both types of collaboration, even supporting disconnected work. In this paper we analyze the limitations of existing systems and propose a data management solution that overcomes such limitations. The proposed concurrency control algorithm, based on conflict-free data types, builds on the ideas previously developed for synchronous collaboration, extending them to support asynchronous collaboration. Our solution also includes the necessary information for providing comprehensive awareness information to users. The evaluation of our algorithm shows that comparing our solution with traditional solutions in collaborative editing, the conflict resolution strategy proposed in this paper leads to results closer to the ones expected by users

Moving elements in list CRDTs

Conflict-free Replicated Data Types (CRDTs) for lists allow multiple users to concurrently insert and delete elements in a shared list object. However, existing algorithms behave poorly when users concurrently move list elements to a new position (i.e. reorder the elements in the list). We demonstrate the need for such a move operation, and describe an algorithm that extends a list CRDT with an explicit move operation. Our algorithm can be used in conjunction with any existing list CRDT algorithm. In addition to moving a single list element, we also discuss the open problem of moving ranges of elements.Leverhulme Trust Early Career Fellowship Isaac Newton Trus