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

Marti Raudsepp <marti(at)juffo(dot)org> writes:
> On Fri, Nov 5, 2010 at 21:20, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> What's that got to do with it?

> I'm not sure what you're asking.

> Surely changing the default wal_sync_method for all OSes in
> maintenance releases is out of the question, no?

Well, if we could leave well enough alone it would be fine with me,
but I think our hand is being forced by the Linux kernel hackers.
I don't really think that "change the default on Linux" is that
much nicer than "change the default everywhere" when it comes to
what we ought to consider back-patching. In any case, you're getting
ahead of the game: we need to decide on the desired behavior first and
then think about what to patch. Do the performance results that were
cited show that open_dsync is generally inferior to fdatasync? If so,
why would we think that that conclusion is Linux-specific?

regards, tom lane