Re: [PATCH] Revert default wal_sync_method to fdatasync on Linux 2.6.33+

Tom Lane wrote:
> Josh Berkus <josh(at)agliodbs(dot)com> writes:
> > Making it support O_DIRECT would be possible but more complex; I don't
> > see the point unless we think we're going to have open_sync_with_odirect
> > as a seperate option.
>
> Whether it's complex or not isn't really the issue. The issue is that
> what test_fsync is testing had better match what the backend does, or
> people will be making choices based on not-comparable test results.
> I think we should have test_fsync just automatically fold in O_DIRECT
> the same way the backend does.

The problem is that O_DIRECT was not implemented in macros but rather
down in the code:

if (!XLogIsNeeded() && !am_walreceiver)
o_direct_flag = PG_O_DIRECT;

Which means if we just export the macros, we would still not have caught
this. I would like to share all the defines --- I am just saying it
isn't trivial.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +