On Sun, May 29, 2022 at 4:29 AM 浩辰 何 <hehaoc...@hotmail.com> wrote: > Furthermore, the results above are also related to IO API supported by OS. > MySQL support synchronized IO and Linux libaio. It seems > that PostgreSQL only supports synchronized IO, so shall we support more IO > engines? like io_uring which is very popular in recent years.
Hi Haochen, There is an active project to bring these things to PostgreSQL. https://wiki.postgresql.org/wiki/AIO has some information and links. The short version is that there is a development patch set to add these GUCs: io_method=worker,io_uring,posix_aio,iocp,... io_data_direct=on,off io_wal_direct=on,off It also adds a bunch of specialised logic that knows how to initiate IO in key places (scans, writeback, recovery, ...), because it's not enough to just turn off kernel I/O buffering, we also have to do all the work the kernel is doing for us or performance will be terrible.
