Re: Patch: add timing of buffer I/O requests - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Patch: add timing of buffer I/O requests
Date
Msg-id CA+TgmoZL1G6XwZCu06MiDG0BxMOog1gyzV-W5oWzX+bTyK-ebg@mail.gmail.com
Whole thread Raw
In response to Re: Patch: add timing of buffer I/O requests  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Patch: add timing of buffer I/O requests  ("ktm@rice.edu" <ktm@rice.edu>)
Re: Patch: add timing of buffer I/O requests  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Tue, Apr 10, 2012 at 1:58 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Tue, Apr 10, 2012 at 1:44 PM, Tom Lane <tgl@sss.pgh.pa.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


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: Patch: add timing of buffer I/O requests
Next
From: "ktm@rice.edu"
Date:
Subject: Re: Patch: add timing of buffer I/O requests