Asynchronous IO in Postgres 18: The Backend Engineering Show TL;DR

Postgres 18 just dropped with a bunch of goodies—UUIDv7 support, an “Over explain” module, composite index skip scans and, most talked-about, native asynchronous I/O. In this episode Hussein Nasser walks through the difference between sync vs. async calls, revisits how Postgres 17 handled I/O, and sets the stage for async I/O’s return.

He then dives deep into Postgres 18’s two async modes—worker and io_uring—comparing them to the default sync path, highlights the implementation challenges and performance wins, and teases upcoming improvements (backend writer support, direct I/O tweaks, better worker handling). All that in bite-sized chapters, plus a quick recap at the end.

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