Conviva replaces mmap with io_uring in Rust query engine, sees performance drop

Conviva engineers swapped out memory-mapped I/O (mmap) in favour of io_uring within their Rust-based query engine, expecting a performance boost. The experiment yielded the opposite result, with the engine running slower after the change. The team documented their findings in a technical blog post, offering insight into the real-world trade-offs between the two I/O approaches. The results highlight that io_uring, despite its modern design and growing reputation, does not universally outperform established alternatives like mmap in all workloads.