Horton

Re: O_DIRECT on macOS

Thomas Munro <thomas.munro@gmail.com>

View thread View on postgr.es
From: Thomas Munro <thomas.munro@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-07-19T00:28:34Z
Lists: pgsql-hackers 
On Tue, Jul 13, 2021 at 1:56 PM Andres Freund <andres@anarazel.de> wrote:
> On 2021-07-13 13:25:50 +1200, Thomas Munro wrote:
> > I'm planning to go with that idea (#1), if there are no objections.
>
> The only other viable approach I see is to completely separate our
> internal flag representation from the OS representation and do the whole
> mapping inside fd.c - but that seems like a too big hammer right now.

Agreed.  Pushed!

For the record, Solaris has directio() that could be handled the same
way.  I'm not planning to look into that myself, but patches welcome.
Illumos (née OpenSolaris) got with the programme and added O_DIRECT.
Of our 10-or-so target systems I guess that'd leave just HPUX (judging
by an old man page found on the web) and OpenBSD with no direct I/O
support.

Commits

  1. Don't use #if inside function-like macro arguments.

  2. Support direct I/O on macOS.