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

From Tom Lane
Subject Re: Patch: add timing of buffer I/O requests
Date
Msg-id 10647.1334075231@sss.pgh.pa.us
Whole thread Raw
In response to Re: Patch: add timing of buffer I/O requests  (Magnus Hagander <magnus@hagander.net>)
Responses Re: Patch: add timing of buffer I/O requests  (Magnus Hagander <magnus@hagander.net>)
Re: Patch: add timing of buffer I/O requests  (Greg Smith <greg@2ndQuadrant.com>)
List pgsql-hackers
Magnus Hagander <magnus@hagander.net> writes:
> On Tue, Apr 10, 2012 at 17:58, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Tue, Apr 10, 2012 at 10:06 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> Given that we've whacked pg_stat_statements' behavior around rather
>>> thoroughly in this release, maybe we could get away with redefining
>>> total_time as being measured in msec rather than sec, thereby aligning
>>> units as msec across the board.  It's arguably a smaller deal than the
>>> way we've redefined what the query column contains...
>> 
>> Retyping columns is an awfully good way to produce grumpy users.  Then
>> again, if we're going to do it, it would certainly be better to do it
>> now rather than later, because right now I'm guessing
>> pg_stat_statements is a lot less heavily used than it will be after
>> 9.2 hits shelves.

> Agreed. It's better if we can also change the name of it - provided we
> can come up with a reasonable new name. Then peoples applications will
> break *visibly*, which is a lot  better than breaking invisibly. (This
> is the main reason why we renamed current_query in pg_stat_activity..)

That might be overkill.  Changing the column name will definitely break
anything more specific than "select * from pg_stat_statements".
However, it's less clear that changing the units in which the column is
expressed will break things.  It seems likely to me that nobody out
there is doing anything much more sophisticated than sorting by the
column, and that's still going to work the same.
        regards, tom lane


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