Asynchronous IO in Postgres 18

Postgres 18 just dropped with a bunch of goodies—from UUIDv7 support and a cooler “over” explain module to composite index skip scans—but the real headliner is asynchronous IO. In this episode of The Backend Engineering Show, Hussein walks us through why async matters, how Postgres 17 did it synchronously, and what changed in v18: you get io_method=worker, the new io_uring option, and even the fallback sync mode for compatibility.

Along the way you’ll see timestamped deep dives into how the worker threads work, the performance perks (and pitfalls) of io_uring, and why async IO in Postgres isn’t “done” yet. Plus, there are teasers about direct IO support and more backend writer improvements on the horizon.

Watch on YouTube