Re: [PERFORM] Direct I/O issues

Greg Smith wrote:
> On Thu, 23 Nov 2006, Tom Lane wrote:
>
> > * It does not check for errors (if it had, you might have realized the
> > other problem).
>
> All the test_fsync code needs to check for errors better; there have been
> multiple occasions where I've run that with quesiontable input and it
> didn't complain, it just happily ran and reported times that were almost
> 0.
>
> Thanks for the note about alignment, I had seen something about that in
> the xlog.c but wasn't sure if that was important in this case.
>
> It's very important to the project I'm working on that I get this cleared
> up, and I think I'm in a good position to fix it myself now. I just
> wanted to report the issue and get some initial feedback on what's wrong.
> I'll try to rewrite that code with an eye toward the "Determine optimal
> fdatasync/fsync, O_SYNC/O_DSYNC options" to-do item, which is what I'd
> really like to have.

I have developed a patch that moves the defines into a include file
where they can be used by the backend and test_fsync.c. I have also set
up things so there is proper alignment for O_DIRECT, and added error
checking.

Not sure if people want this for 8.2. I think we can modify
test_fsync.c anytime but the movement of the defines into an include
file is a backend code change.

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

+ If your life is a hard drive, Christ can be your backup. +