Would you please try the attached patch and let me know if it fixes the
problem? I avoided accumulating into a float8.
---------------------------------------------------------------------------
Rocco Altier wrote:
> This still does not fix the problem.
>
> I had done my patch to try to mimic the way 8.0 had handled the math
> with the remainders, but to carry it over another bucket (day).
>
> The problem that I see is that we are taking day_remainder and
> multiplying by USECS_PER_DAY. Which is a double * int64, thus there is
> the precision loss there.
>
> I think initial division by the factor can't be helped, but repeatedly
> doing more floating point math on with it is causing the rounding error.
>
> Thanks,
> -rocco
>
> > -----Original Message-----
> > From: Bruce Momjian [mailto:[EMAIL PROTECTED]
> > Sent: Saturday, July 23, 2005 10:54 AM
> > To: Rocco Altier
> > Cc: Michael Glaesemann; pgsql-patches@postgresql.org;
> > pgsql-hackers@postgresql.org; ohp@pyrenet.fr
> > Subject: Re: [HACKERS] regressin failure on latest CVS
> >
> >
> > Rocco Altier wrote:
> > > This patch fixes the interval regression on my AIX box
> > (kookaburra) by
> > > only doing integer math on the interval, instead of
> > float/double math.
> > >
> > > I think this is the correct way to handle this, since it's
> > an integer
> > > data type.
> > >
> > > I don't know if it will fix Olivier's problem, since I
> > wasn't able to
> > > reproduce it.
> > >
> >
> > I have changed the way I compute the remainder values --- instead of
> > using multiplication, I use division and then subtraction.
> > This should
> > fix your rounding problem. Looking at your fix, I don't see
> > how adding
> > USECS changes things because the factor is already a float,
> > but I think
> > the problem was more the way I was computing the remainders.
> >
> > Patch attached --- let me know if it does not fix your problem.
> >
> > --------------------------------------------------------------
>
>
> ---------------------------(end of broadcast)---------------------------
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>
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
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Index: src/backend/utils/adt/timestamp.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v
retrieving revision 1.145
diff -c -c -r1.145 timestamp.c
*** src/backend/utils/adt/timestamp.c 23 Jul 2005 14:53:21 -0000 1.145
--- src/backend/utils/adt/timestamp.c 23 Jul 2005 18:45:56 -0000
***************
*** 2309,2327 ****
result->time = span->time / factor;
/* Compute remainders */
! month_remainder = span->month / factor - result->month;
! day_remainder = span->day / factor - result->day;
/* Cascade fractions to lower units */
/* fractional months full days into days */
result->day += month_remainder * DAYS_PER_MONTH;
- /* fractional months partial days into time */
- day_remainder += (month_remainder * DAYS_PER_MONTH) -
(int)(month_remainder * DAYS_PER_MONTH);
#ifdef HAVE_INT64_TIMESTAMP
! result->time += day_remainder * USECS_PER_DAY;
#else
! result->time += day_remainder * SECS_PER_DAY;
result->time = JROUND(result->time);
#endif
--- 2309,2328 ----
result->time = span->time / factor;
/* Compute remainders */
! month_remainder = (span->month / factor - result->month);
! day_remainder = (span->day / factor - result->day);
/* Cascade fractions to lower units */
/* fractional months full days into days */
result->day += month_remainder * DAYS_PER_MONTH;
+ /* fractional months partial days into time */
#ifdef HAVE_INT64_TIMESTAMP
! result->time += (day_remainder + month_remainder * DAYS_PER_MONTH -
! (int)(month_remainder *
DAYS_PER_MONTH)) * USECS_PER_DAY;
#else
! result->time += (day_remainder + month_remainder * DAYS_PER_MONTH -
! (int)(month_remainder *
DAYS_PER_MONTH)) * SECS_PER_DAY;
result->time = JROUND(result->time);
#endif
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