Re: PostgreSQL's handling of fsync() errors is unsafe and risks data loss at least on XFS

On Mon, Apr 09, 2018 at 12:29:16PM -0700, Andres Freund wrote:
> On 2018-04-09 21:26:21 +0200, Anthony Iliopoulos wrote:
> > What about having buffered IO with implied fsync() atomicity via
> > O_SYNC?
> 
> You're kidding, right?  We could also just add sleep(30)'s all over the
> tree, and hope that that'll solve the problem.  There's a reason we
> don't permanently fsync everything. Namely that it'll be way too slow.

I am assuming you can apply the same principle of selectively using O_SYNC
at times and places that you'd currently actually call fsync().

Also assuming that you'd want to have a backwards-compatible solution for
all those kernels that don't keep the pages around, irrespective of future
fixes. Short of loading a kernel module and dealing with the problem directly,
the only other available options seem to be either O_SYNC, O_DIRECT or ignoring
the issue.

Best regards,
Anthony