To Vote Before Decide: A Logless One-Phase Commit Protocol for Highly-Available Datastores

TL;DR

This paper introduces HACommit, a logless one-phase commit protocol for highly-available datastores that reduces commit time significantly by having participants vote before the client decides, enabling faster transaction processing.

Contribution

The paper proposes HACommit, the first logless one-phase commit protocol that allows transaction participants to vote before the client decides, improving efficiency over existing methods.

Findings

HACommit outperforms recent atomic commit solutions in experiments.

In the best case, HACommit commits in one fifth of 2PC time.

HACommit enables transaction data visibility within one communication roundtrip.

Abstract

Highly-available datastores are widely deployed for online applications. However, many online applications are not contented with the simple data access interface currently provided by highly-available datastores. Distributed transaction support is demanded by applications such as large-scale online payment used by Alipay or Paypal. Current solutions to distributed transaction can spend more than half of the whole transaction processing time in distributed commit. An efficient atomic commit protocol is highly desirable. This paper presents the HACommit protocol, a logless one-phase commit protocol for highly-available systems. HACommit has transaction participants vote for a commit before the client decides to commit or abort the transaction; in comparison, the state-of-the-art practice for distributed commit is to have the client decide before participants vote. The change enables the removal of both the participant logging and the coordinator logging steps in the distributed commit process; it also makes possible that, after the client initiates the transaction commit, the transaction data is visible to other transactions within one communication roundtrip time (i.e., one phase). In the evaluation with extensive experiments, HACommit outperforms recent atomic commit solutions for highly-available datastores under different workloads. In the best case, HACommit can commit in one fifth of the time 2PC does.