Horton

Re: Direct I/O

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, Christoph Berg <myon@debian.org>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2023-04-13T02:04:59Z
Lists: pgsql-hackers 
Thanks both for looking, and thanks for the explanation Ilmari.
Pushed with your improvements.  The 4 CI systems run the tests
(Windows and Mac by special always-expected-to-work case, Linux and
FreeBSD by successful pre-flight perl test of O_DIRECT), and I also
tested three unusual systems, two that skip for different reasons and
one that will henceforth run this test on the build farm so I wanted
to confirm locally first:

Linux/tmpfs: 1..0 # SKIP pre-flight test if we can open a file with
O_DIRECT failed: Invalid argument
OpenBSD:     t/004_io_direct.pl .............. skipped: no O_DIRECT
illumos:     t/004_io_direct.pl .............. ok

(Format different because those last two are autoconf, no meson on my
collection of Vagrant images yet...)

Commits

  1. Rename hook functions for debug_io_direct to match variable name.

  2. Rename io_direct to debug_io_direct.

  3. Skip the 004_io_direct.pl test if a pre-flight check fails.

  4. Use higher wal_level for 004_io_direct.pl.

  5. Skip \password TAP test on old IPC::Run versions

  6. Add io_direct setting (developer-only).

  7. Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.

  8. Add palloc_aligned() to allow aligned memory allocations

  9. initdb: When running CREATE DATABASE, use STRATEGY = WAL_COPY.