LogPlayer: Fault-tolerant Exactly-once Delivery using gRPC Asynchronous Streaming

TL;DR

LogPlayer is a fault-tolerant system that ensures in-order, exactly-once delivery of transactional logs to storage shards using gRPC streaming, verified by formal methods and outperforming Kafka in efficiency.

Contribution

This paper introduces LogPlayer, a novel fault-tolerant delivery system with formal correctness guarantees and superior efficiency compared to existing solutions like Kafka.

Findings

Guarantees in-order, exactly-once delivery despite failures

Achieves sub-millisecond latency in delivery

Outperforms Apache Kafka in efficiency

Abstract

In this paper, we present the design of our LogPlayer that is a component responsible for fault-tolerant delivery of transactional mutations recorded on a WAL to the backend storage shards. LogPlayer relies on gRPC for asynchronous streaming. However, the design provided in this paper can be used with other asynchronous streaming platforms. We model check the correctness of LogPlayer by TLA+. In particular, our TLA+ specification shows that LogPlayer guarantees in-order exactly-once delivery of WAL entries to the storage shards, even in the presence of shards or LogPlayer failures. Our experiments show LogPlayer is capable of efficient delivery with sub-millisecond latency, and it is significantly more efficient than Apache Kafka for designing a WAL system with exactly-once guarantee.