Re: Patch: add timing of buffer I/O requests

On Tue, Apr 10, 2012 at 02:01:02PM -0400, Robert Haas wrote:
> On Tue, Apr 10, 2012 at 1:58 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >> On Tue, Apr 10, 2012 at 1:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >>> Huh?  I understood what you said upthread to be that we have two ways
> >>> in existing releases (anything unreleased has zero standing in this
> >>> discussion): float8 sec in pg_stat_statements.total_time, and
> >>> int8 msec everywhere else.  Did I miss something?
> >
> >> We also have int8 usec floating around.  But even if we didn't, float8
> >> msec would be a new one, regardless of whether it would be third or
> >> fourth...
> >
> > It would still be the second one, because it would replace the only use
> > of float8 sec, no?  And more to the point, it converges us on msec being
> > the only exposed unit.
> >
> > The business about underlying microseconds is maybe not so good, but
> > I don't think we want to touch that right now.  In the long run
> > I think it would make sense to converge on float8 msec as being the
> > standard for exposed timing values, because that is readily adaptable to
> > the underlying data having nsec or even better precision.
>
> Hmm. Maybe we should think about numeric ms, which would have all the
> same advantages but without the round-off error.
>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>

They are also a lot bigger with tons of added overhead. :)

Regards,
Ken