Fries: Fast and Consistent Runtime Reconfiguration in Dataflow Systems with Transactional Guarantees (Extended Version)

TL;DR

Fries introduces a fast, consistent runtime reconfiguration method for dataflow systems that minimizes delay and supports fault tolerance, leveraging fast control messages for on-the-fly updates without system downtime.

Contribution

The paper presents Fries, a novel reconfiguration scheduler that ensures consistency and low latency in dataflow systems using control messages, improving over epoch-based methods.

Findings

Fries achieves faster reconfiguration times compared to epoch-based schedulers.

The technique maintains consistency during reconfiguration in various dataflow classes.

Experimental results demonstrate improved performance and fault tolerance in cluster environments.

Abstract

A computing job in a big data system can take a long time to run, especially for pipelined executions on data streams. Developers often need to change the computing logic of the job such as fixing a loophole in an operator or changing the machine learning model in an operator with a cheaper model to handle a sudden increase of the data-ingestion rate. Recently many systems have started supporting runtime reconfigurations to allow this type of change on the fly without killing and restarting the execution. While the delay in reconfiguration is critical to performance, existing systems use epochs to do runtime reconfigurations, which can cause a long delay. In this paper we develop a new technique called Fries that leverages the emerging availability of fast control messages in many systems, since these messages can be sent without being blocked by data messages. We formally define consistency in runtime reconfigurations, and develop a Fries scheduler with consistency guarantees. The technique not only works for different classes of dataflows, but also works for parallel executions and supports fault tolerance. Our extensive experimental evaluation on clusters show the advantages of this technique compared to epoch-based schedulers.