High-Performance DBMSs with io_uring: When and How to use it

TL;DR

This paper investigates how to effectively leverage Linux's io_uring interface in modern database systems, providing guidelines and demonstrating performance improvements through practical case studies and detailed analysis.

Contribution

It offers a comprehensive analysis of io_uring's benefits and limitations in database I/O, along with practical guidelines for optimal integration and a case study on PostgreSQL.

Findings

io_uring can significantly improve I/O performance when used with proper optimizations

Advanced features like registered buffers enhance throughput in specific workloads

Applying guidelines to PostgreSQL yields a 14% performance boost

Abstract

We study how modern database systems can leverage the Linux io_uring interface for efficient, low-overhead I/O. io_uring is an asynchronous system call batching interface that unifies storage and network operations, addressing limitations of existing Linux I/O interfaces. However, naively replacing traditional I/O interfaces with io_uring does not necessarily yield performance benefits. To demonstrate when io_uring delivers the greatest benefits and how to use it effectively in modern database systems, we evaluate it in two use cases: Integrating io_uring into a storage-bound buffer manager and using it for high-throughput data shuffling in network-bound analytical workloads. We further analyze how advanced io_uring features, such as registered buffers and passthrough I/O, affect end-to-end performance. Our study shows when low-level optimizations translate into tangible system-wide gains and how architectural choices influence these benefits. Building on these insights, we derive practical guidelines for designing I/O-intensive systems using io_uring and validate their effectiveness in a case study of PostgreSQL's recent io_uring integration, where applying our guidelines yields a performance improvement of 14%.