BarQL: Collaborating Through Change

TL;DR

BarQL introduces a general-purpose state-update language and a mutation framework that enables reasoning about algebraic properties of updates, facilitating optimized collaborative web applications.

Contribution

The paper presents mutation languages and BarQL, a novel framework and language for reasoning about and optimizing shared state updates in collaborative applications.

Findings

Mutation languages enable algebraic reasoning about updates.

BarQL supports a wide range of update operations.

Framework improves efficiency of collaborative applications.

Abstract

Applications such as Google Docs, Office 365, and Dropbox show a growing trend towards incorporating multi-user live collaboration functionality into web applications. These collaborative applications share a need to efficiently express shared state, and a common strategy for doing so is a shared log abstraction. Extensive research efforts on log abstractions by the database, programming languages, and distributed systems communities have identified a variety of optimization techniques based on the algebraic properties of updates (i.e., pairwise commutativity, subsumption, and idempotence). Although these techniques have been applied to specific applications and use-cases, to the best of our knowledge, no attempt has been made to create a general framework for such optimizations in the context of a non-trivial update language. In this paper, we introduce mutation languages, a low-level framework for reasoning about the algebraic properties of state updates, or mutations. We define BarQL, a general purpose state-update language, and show how mutation languages allow us to reason about the algebraic properties of updates expressed in BarQ L .