Re: checkpointer continuous flushing

On Sat, Jan 9, 2016 at 6:08 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>
> On 2016-01-09 18:04:39 +0530, Amit Kapila wrote:
> > On Thu, Jan 7, 2016 at 4:21 PM, Andres Freund <andres(at)anarazel(dot)de>
wrote:
> > >
> > > On 2016-01-07 11:27:13 +0100, Fabien COELHO wrote:
> > > > I read your patch and I know what I want to try to have a small and
> > simple
> > > > fix. I must admit that I have not really understood in which
condition
> > the
> > > > checkpointer would decide to close a file, but that does not mean
that
> > the
> > > > potential issue should not be addressed.
> > >
> > > There's a trivial example: Consider three tablespaces and
> > > max_files_per_process = 2. The balancing can easily cause three files
> > > being flushed at the same time.
> > >
> >
> > Won't the same thing can occur without patch in mdsync() and can't
> > we handle it in same way? In particular, I am referring to below code:
>
> I don't see how that's corresponding - the problem is that current
> proposed infrastructure keeps a kernel level (or fd.c in my versio) fd
> open in it's 'pending flushes' struct. But since that isn't associated
> with fd.c opening/closing files that fd isn't very meaningful.
>

Okay, but I think that is the reason why you are worried that it is possible
to issue sync_file_range() on a closed file, is that right or am I missing
something?

With Regards,
Amit Kapila.
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