Subject: pgsql: aio: Add io_method=io_uring

From: Andres Freund <[email-masked]>
Date: Thu, 27 Mar 2025 00:15:53 +0000

aio: Add io_method=io_uring

Performing AIO using io_uring can be considerably faster than
io_method=worker, particularly when lots of small IOs are issued, as
a) the context-switch overhead for worker based AIO becomes more significant
b) the number of IO workers can become limiting

io_uring, however, is linux specific and requires an additional compile-time
dependency (liburing).

This implementation is fairly simple and there are substantial optimization
opportunities.

The description of the existing AIO_IO_COMPLETION wait event is updated to
make the difference between it and the new AIO_IO_URING_EXECUTION clearer.

Reviewed-by: Noah Misch <[email-masked]>
Reviewed-by: Jakub Wartak <[email-masked]>
Discussion: https://postgr.es/m/uvrtrknj4kdytuboidbhwclo4gxhswwcpgadptsjvjqcluzmah%40brqs62irg4dt
Discussion: https://postgr.es/m/[email-masked]
Discussion: https://postgr.es/m/stj36ea6yyhoxtqkhpieia2z4krnam7qyetc57rfezgk4zgapf@gcnactj4z56m

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/c325a7633fcb33dbd73f46ddbbe91e95ddf3b227

Modified Files
--------------
.cirrus.tasks.yml                               |   3 +
doc/src/sgml/config.sgml                        |   8 +
src/backend/storage/aio/Makefile                |   1 +
src/backend/storage/aio/aio.c                   |  41 ++
src/backend/storage/aio/aio_io.c                |  22 ++
src/backend/storage/aio/meson.build             |   1 +
src/backend/storage/aio/method_io_uring.c       | 484 ++++++++++++++++++++++++
src/backend/storage/lmgr/lwlock.c               |   1 +
src/backend/utils/activity/wait_event_names.txt |   4 +-
src/backend/utils/misc/postgresql.conf.sample   |   3 +-
src/include/storage/aio.h                       |   8 +
src/include/storage/aio_internal.h              |  13 +
src/include/storage/lwlock.h                    |   1 +
src/tools/pgindent/typedefs.list                |   1 +
14 files changed, 589 insertions(+), 2 deletions(-)

---

From: Andres Freund <[email-masked]>
Date: Wed, 26 Mar 2025 21:11:05 -0400

Hi,

> aio: Add io_method=io_uring

FWIW, the BF failure on culicidae looks to be independent to me
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=culicidae&dt=2025-03-27%2000%3A16%3A30

The relevant line from the log is:
2025-03-27 00:20:05.478 UTC [353525][not initialized][:0] FATAL:  incorrect checksum in control file

See also
https://postgr.es/m/7ff9de7f-7203-cad9-76d9-45497cbedac7%40gmail.com

Greetings,

Andres Freund