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

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
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