Thread: Re: [BUGS] BUG #1927: incorrect timestamp returned

Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Bruce Momjian
Date:
Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Right.  We allow leap seconds for any date/time.  Are you saying we
> > should only allow them for certain dates/times?
>
> No, his point is the funny roundoff behavior.
>
> regression=# select timestamp '2005-09-23 23:59:59.999999';
>          timestamp
> ----------------------------
>  2005-09-23 23:59:59.999999
> (1 row)
>
> regression=# select timestamp '2005-09-23 23:59:59.9999999';
>        timestamp
> ------------------------
>  2005-09-23 23:59:60.00
> (1 row)
>
> regression=# select timestamp '2005-09-23 23:59:59.99999999';
>       timestamp
> ---------------------
>  2005-09-24 00:00:00
> (1 row)

I did some research on this.  The difference is caused by the place in
the code where the rounding happens.  Here is the simple case.  The
second line is the return value, "double", from timestamp_in():

    test=> select timestamp '2005-09-23 23:59:59.999999';
             timestamp
    ----------------------------
     2005-09-23 23:59:59.999999
     180835199.99999899

Here is one where the rounding happens after timestamp_in() returns:

    test=> select timestamp '2005-09-23 23:59:59.9999999';
           timestamp
    ------------------------
     2005-09-23 23:59:60.00
     180835199.99999991

and in this case the rounding happens inside timestamp_in():

    test=> select timestamp '2005-09-23 23:59:59.99999999';
          timestamp
    ---------------------
     2005-09-24 00:00:00
     180835200

Looks like "time" has a similar problem:

    test=> select time '2005-09-23 23:59:59.99999999';
           time
    -------------------
     23:59:59.99999999
    (1 row)

    test=> select time '2005-09-23 23:59:59.99999999999';
        time
    -------------
     23:59:60.00
    (1 row)

    test=> select time '2005-09-23 23:59:59.999999999999';
       time
    ----------
     24:00:00
    (1 row)

I have gone through the code and identified all the places that need
JROUND, basically places where we do complex calculations that include
fsec (fractional seconds).  This only affects timestamp=double backends,
not timestamp=int64.

The patch fixes all the test cases above, and passes all regression
tests.

--
  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
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: src/backend/utils/adt/date.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/date.c,v
retrieving revision 1.120
diff -c -c -r1.120 date.c
*** src/backend/utils/adt/date.c    9 Sep 2005 02:31:49 -0000    1.120
--- src/backend/utils/adt/date.c    7 Oct 2005 21:00:34 -0000
***************
*** 920,926 ****
      *result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec)
                  * USECS_PER_SEC) + fsec;
  #else
!     *result = ((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec;
  #endif
      return 0;
  }
--- 920,926 ----
      *result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec)
                  * USECS_PER_SEC) + fsec;
  #else
!     *result = JROUND(((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec);
  #endif
      return 0;
  }
***************
*** 1345,1351 ****
      result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                  USECS_PER_SEC) + fsec;
  #else
!     result = ((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec;
  #endif

      PG_RETURN_TIMEADT(result);
--- 1345,1351 ----
      result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                  USECS_PER_SEC) + fsec;
  #else
!     result = JROUND(((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec);
  #endif

      PG_RETURN_TIMEADT(result);
***************
*** 1382,1388 ****
      result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                  USECS_PER_SEC) + fsec;
  #else
!     result = ((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec;
  #endif

      PG_RETURN_TIMEADT(result);
--- 1382,1388 ----
      result = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                  USECS_PER_SEC) + fsec;
  #else
!     result = JROUND(((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec);
  #endif

      PG_RETURN_TIMEADT(result);
***************
*** 1712,1718 ****
      result->time = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                      USECS_PER_SEC) + fsec;
  #else
!     result->time = ((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec;
  #endif
      result->zone = tz;

--- 1712,1718 ----
      result->time = ((((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec) *
                      USECS_PER_SEC) + fsec;
  #else
!     result->time = JROUND(((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec + fsec);
  #endif
      result->zone = tz;

Index: src/backend/utils/adt/timestamp.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v
retrieving revision 1.153
diff -c -c -r1.153 timestamp.c
*** src/backend/utils/adt/timestamp.c    9 Sep 2005 06:46:14 -0000    1.153
--- src/backend/utils/adt/timestamp.c    7 Oct 2005 21:00:38 -0000
***************
*** 1255,1261 ****
  static double
  time2t(const int hour, const int min, const int sec, const fsec_t fsec)
  {
!     return (((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec;
  }    /* time2t() */
  #endif

--- 1255,1261 ----
  static double
  time2t(const int hour, const int min, const int sec, const fsec_t fsec)
  {
!     return JROUND((((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec);
  }    /* time2t() */
  #endif

***************
*** 3505,3511 ****
                  result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + (fsec / 1000000.0)) / (double)SECS_PER_DAY;
  #else
!                 result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + fsec) / (double)SECS_PER_DAY;
  #endif
                  break;
--- 3505,3511 ----
                  result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + (fsec / 1000000.0)) / (double)SECS_PER_DAY;
  #else
!                 result += JROUND((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + fsec) / (double)SECS_PER_DAY;
  #endif
                  break;
***************
*** 3733,3739 ****
                  result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + (fsec / 1000000.0)) / (double)SECS_PER_DAY;
  #else
!                 result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + fsec) / (double)SECS_PER_DAY;
  #endif
                  break;
--- 3733,3739 ----
                  result += ((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + (fsec / 1000000.0)) / (double)SECS_PER_DAY;
  #else
!                 result += JROUND((((tm->tm_hour * MINS_PER_HOUR) + tm->tm_min) * SECS_PER_MINUTE) +
                              tm->tm_sec + fsec) / (double)SECS_PER_DAY;
  #endif
                  break;
Index: src/interfaces/ecpg/pgtypeslib/timestamp.c
===================================================================
RCS file: /cvsroot/pgsql/src/interfaces/ecpg/pgtypeslib/timestamp.c,v
retrieving revision 1.31
diff -c -c -r1.31 timestamp.c
*** src/interfaces/ecpg/pgtypeslib/timestamp.c    22 Jul 2005 19:00:55 -0000    1.31
--- src/interfaces/ecpg/pgtypeslib/timestamp.c    7 Oct 2005 21:00:40 -0000
***************
*** 27,33 ****
  static double
  time2t(const int hour, const int min, const int sec, const fsec_t fsec)
  {
!     return (((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec;
  }    /* time2t() */
  #endif

--- 27,33 ----
  static double
  time2t(const int hour, const int min, const int sec, const fsec_t fsec)
  {
!     return     JROUND((((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec);
  }    /* time2t() */
  #endif


Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Tom Lane
Date:
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> I have gone through the code and identified all the places that need
> JROUND, basically places where we do complex calculations that include
> fsec (fractional seconds).  This only affects timestamp=double backends,
> not timestamp=int64.

I'm not sure I like this approach.  What you've essentially done is to
remove any possibility of getting more than six digits of fractional
precision out of a "double" timestamp --- and impose nontrivial
calculation overhead to make sure that double doesn't have any extra
precision.

I think it'd probably be better to just fix the rounding during display.

            regards, tom lane

Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Bruce Momjian
Date:
Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > I have gone through the code and identified all the places that need
> > JROUND, basically places where we do complex calculations that include
> > fsec (fractional seconds).  This only affects timestamp=double backends,
> > not timestamp=int64.
>
> I'm not sure I like this approach.  What you've essentially done is to
> remove any possibility of getting more than six digits of fractional
> precision out of a "double" timestamp --- and impose nontrivial
> calculation overhead to make sure that double doesn't have any extra
> precision.
>
> I think it'd probably be better to just fix the rounding during display.

If we do that, should we remove some the existing JROUND calls in the
code?  I think we have to do this consistently, at least.

Looking at the code, it seems JROUND() is used only in a few places:

    dt2time
    tm2interval
    time2t
    dt2local

What is the pattern on when to use it?

Also, I don't see how rounding is going to fix the problem that the
value is actually _rounded_ at different stages, meaning when you are
doing the output you don't know what came in, as outlined by my
timestamp_in data.

--
  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
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Tom Lane
Date:
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> I think it'd probably be better to just fix the rounding during display.

> If we do that, should we remove some the existing JROUND calls in the
> code?  I think we have to do this consistently, at least.

Yeah, I was looking at that --- I think most if not all of the existing
JROUND calls ought to go away.  Will try to work up a full patch over
the weekend.

> Also, I don't see how rounding is going to fix the problem that the
> value is actually _rounded_ at different stages, meaning when you are
> doing the output you don't know what came in, as outlined by my
> timestamp_in data.

I think the solution is that timestamp_out needs to decide how many
fractional digits it wants to display, and then round off the input
accordingly, *before* it breaks the input down into y/m/d/h/m/s fields.
This "60.00" business is happening because the rounding is done only on
the seconds-and-fractional-seconds field.

            regards, tom lane

Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Bruce Momjian
Date:
Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Tom Lane wrote:
> >> I think it'd probably be better to just fix the rounding during display.
>
> > If we do that, should we remove some the existing JROUND calls in the
> > code?  I think we have to do this consistently, at least.
>
> Yeah, I was looking at that --- I think most if not all of the existing
> JROUND calls ought to go away.  Will try to work up a full patch over
> the weekend.

OK

> > Also, I don't see how rounding is going to fix the problem that the
> > value is actually _rounded_ at different stages, meaning when you are
> > doing the output you don't know what came in, as outlined by my
> > timestamp_in data.
>
> I think the solution is that timestamp_out needs to decide how many
> fractional digits it wants to display, and then round off the input
> accordingly, *before* it breaks the input down into y/m/d/h/m/s fields.
> This "60.00" business is happening because the rounding is done only on
> the seconds-and-fractional-seconds field.

Well, the testing showed that the one with the most 9's was actually
rounded up to a whole number by timestamp_in, meaning we never have a
chance to adjust it in timestamp_out.  I am assuming you will be able to
round the middle test value up to a whole number in timestamp_out so the
60 number will disappear.

--
  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
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Re: [BUGS] BUG #1927: incorrect timestamp returned

From
Tom Lane
Date:
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> I think the solution is that timestamp_out needs to decide how many
>> fractional digits it wants to display, and then round off the input
>> accordingly, *before* it breaks the input down into y/m/d/h/m/s fields.
>> This "60.00" business is happening because the rounding is done only on
>> the seconds-and-fractional-seconds field.

> Well, the testing showed that the one with the most 9's was actually
> rounded up to a whole number by timestamp_in, meaning we never have a
> chance to adjust it in timestamp_out.  I am assuming you will be able to
> round the middle test value up to a whole number in timestamp_out so the
> 60 number will disappear.

After further thought I've realized that the current methodology for
applying JROUND (ie, to apply it to a whole timestamp or time value)
is fundamentally bogus.  The macro is trying to round off to six fraction
digits, but if you've got many digits on the left side of the decimal point
then you cannot guarantee that six fraction digits of precision are
available to work with.  It is *only* sensible to JROUND a value
representing a fractional-seconds field (or possibly seconds +
fractional seconds).  Accordingly, the majority of the JROUND calls in
the existing code are indeed bogus and should go away.  The only one
that's not bogus is the one in dt2time(), which is properly applied to a
fractional second ... but the problem with that one is that there's no
provision for coping with the possibility that the fractional second
rounds up to 1.0.  In that situation, we need to be able to propagate
the roundoff to higher fields to avoid the "23:59:60" syndrome.

Since dt2time doesn't have a way to propagate the roundoff into the date
part, we can't fix this right there.  It needs to be handled at the
caller level (timestamp2tm and related routines).

Attached is a proposed patch that cleans this up.  It's not quite
complete because I haven't propagated the changes into ecpglib,
but I thought I could put it out for comment in this form.

The patch does the following:

1. Replace JROUND with TSROUND (to round to MAX_TIMESTAMP_PRECISION
places) and TIMEROUND (to round to MAX_TIME_PRECISION places).

2. Remove JROUND calls in calculational routines.

3. In timestamp2tm, time2tm, timetz2tm, and interval2tm, round off
the fractional-seconds field to the right number of places, check
for rounding up to 1, and cope as needed.

4. Make the sprintf field width in EncodeTimeOnly match
MAX_TIME_PRECISION.  Because it was only printing 9 digits and not 10,
there were cases where a properly rounded fractional time would still
print as "60.0".  (I think at some point we reduced it from 10 to 9
as a hacky way of dealing with a different bug report ... but now I
feel we've gotten the right solution at last.)

The patch passes the regression tests and appears to fix the problems.

Comments?

            regards, tom lane


*** contrib/btree_gist/btree_ts.c.orig    Fri Jul  1 09:44:55 2005
--- contrib/btree_gist/btree_ts.c    Sat Oct  8 13:12:37 2005
***************
*** 122,130 ****
          *gmt -= (tz * INT64CONST(1000000));
  #else
          *gmt -= tz;
-         *gmt = JROUND(*gmt);
  #endif
-
      }
      return gmt;
  }
--- 122,128 ----
*** src/backend/utils/adt/date.c.orig    Thu Sep  8 22:31:49 2005
--- src/backend/utils/adt/date.c    Sat Oct  8 13:12:45 2005
***************
*** 944,953 ****
--- 944,961 ----
  #else
      double        trem;

+ recalc:
      trem = time;
      TMODULO(trem, tm->tm_hour, (double)SECS_PER_HOUR);
      TMODULO(trem, tm->tm_min, (double)SECS_PER_MINUTE);
      TMODULO(trem, tm->tm_sec, 1.0);
+     trem = TIMEROUND(trem);
+     /* roundoff may need to propagate to higher-order fields */
+     if (trem >= 1.0)
+     {
+         time = ceil(time);
+         goto recalc;
+     }
      *fsec = trem;
  #endif

***************
*** 1837,1845 ****
--- 1845,1861 ----
  #else
      double        trem = time->time;

+ recalc:
      TMODULO(trem, tm->tm_hour, (double)SECS_PER_HOUR);
      TMODULO(trem, tm->tm_min, (double)SECS_PER_MINUTE);
      TMODULO(trem, tm->tm_sec, 1.0);
+     trem = TIMEROUND(trem);
+     /* roundoff may need to propagate to higher-order fields */
+     if (trem >= 1.0)
+     {
+         trem = ceil(time->time);
+         goto recalc;
+     }
      *fsec = trem;
  #endif

*** src/backend/utils/adt/datetime.c.orig    Sat Jul 23 10:25:33 2005
--- src/backend/utils/adt/datetime.c    Sat Oct  8 13:12:46 2005
***************
*** 3488,3495 ****
      sprintf(str, "%02d:%02d", tm->tm_hour, tm->tm_min);

      /*
!      * Print fractional seconds if any.  The field widths here should be
!      * at least equal to the larger of MAX_TIME_PRECISION and
       * MAX_TIMESTAMP_PRECISION.
       */
      if (fsec != 0)
--- 3488,3495 ----
      sprintf(str, "%02d:%02d", tm->tm_hour, tm->tm_min);

      /*
!      * Print fractional seconds if any.  The fractional field widths
!      * here should be equal to the larger of MAX_TIME_PRECISION and
       * MAX_TIMESTAMP_PRECISION.
       */
      if (fsec != 0)
***************
*** 3497,3503 ****
  #ifdef HAVE_INT64_TIMESTAMP
          sprintf(str + strlen(str), ":%02d.%06d", tm->tm_sec, fsec);
  #else
!         sprintf(str + strlen(str), ":%012.9f", tm->tm_sec + fsec);
  #endif
          TrimTrailingZeros(str);
      }
--- 3497,3503 ----
  #ifdef HAVE_INT64_TIMESTAMP
          sprintf(str + strlen(str), ":%02d.%06d", tm->tm_sec, fsec);
  #else
!         sprintf(str + strlen(str), ":%013.10f", tm->tm_sec + fsec);
  #endif
          TrimTrailingZeros(str);
      }
*** src/backend/utils/adt/timestamp.c.orig    Fri Sep  9 02:46:14 2005
--- src/backend/utils/adt/timestamp.c    Sat Oct  8 13:35:21 2005
***************
*** 998,1007 ****
      *min = time / SECS_PER_MINUTE;
      time -= (*min) * SECS_PER_MINUTE;
      *sec = time;
!     *fsec = JROUND(time - *sec);
  #endif
-
-     return;
  }    /* dt2time() */


--- 998,1005 ----
      *min = time / SECS_PER_MINUTE;
      time -= (*min) * SECS_PER_MINUTE;
      *sec = time;
!     *fsec = time - *sec;
  #endif
  }    /* dt2time() */


***************
*** 1038,1045 ****
  #endif
      }

-     time = dt;
  #ifdef HAVE_INT64_TIMESTAMP
      TMODULO(time, date, USECS_PER_DAY);

      if (time < INT64CONST(0))
--- 1036,1043 ----
  #endif
      }

  #ifdef HAVE_INT64_TIMESTAMP
+     time = dt;
      TMODULO(time, date, USECS_PER_DAY);

      if (time < INT64CONST(0))
***************
*** 1047,1072 ****
          time += USECS_PER_DAY;
          date -= 1;
      }
  #else
      TMODULO(time, date, (double)SECS_PER_DAY);

      if (time < 0)
      {
          time += SECS_PER_DAY;
!         date -=1;
      }
- #endif

      /* add offset to go from J2000 back to standard Julian date */
      date += POSTGRES_EPOCH_JDATE;

      /* Julian day routine does not work for negative Julian days */
!     if (date <0 || date >(Timestamp) INT_MAX)
          return -1;

      j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
      dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);

      /* Done if no TZ conversion wanted */
      if (tzp == NULL)
      {
--- 1045,1097 ----
          time += USECS_PER_DAY;
          date -= 1;
      }
+
+     /* add offset to go from J2000 back to standard Julian date */
+     date += POSTGRES_EPOCH_JDATE;
+
+     /* Julian day routine does not work for negative Julian days */
+     if (date < 0 || date > (Timestamp) INT_MAX)
+         return -1;
+
+     j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+     dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);
  #else
+     time = dt;
      TMODULO(time, date, (double)SECS_PER_DAY);

      if (time < 0)
      {
          time += SECS_PER_DAY;
!         date -= 1;
      }

      /* add offset to go from J2000 back to standard Julian date */
      date += POSTGRES_EPOCH_JDATE;

+ recalc_d:
      /* Julian day routine does not work for negative Julian days */
!     if (date < 0 || date > (Timestamp) INT_MAX)
          return -1;

      j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+ recalc_t:
      dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);

+     *fsec = TSROUND(*fsec);
+     /* roundoff may need to propagate to higher-order fields */
+     if (*fsec >= 1.0)
+     {
+         time = ceil(time);
+         if (time >= (double)SECS_PER_DAY)
+         {
+             time = 0;
+             date += 1;
+             goto recalc_d;
+         }
+         goto recalc_t;
+     }
+ #endif
+
      /* Done if no TZ conversion wanted */
      if (tzp == NULL)
      {
***************
*** 1216,1224 ****
--- 1241,1257 ----
      tm->tm_sec = time / USECS_PER_SEC;
      *fsec = time - (tm->tm_sec * USECS_PER_SEC);
  #else
+ recalc:
      TMODULO(time, tm->tm_hour, (double)SECS_PER_HOUR);
      TMODULO(time, tm->tm_min, (double)SECS_PER_MINUTE);
      TMODULO(time, tm->tm_sec, 1.0);
+     time = TSROUND(time);
+     /* roundoff may need to propagate to higher-order fields */
+     if (time >= 1.0)
+     {
+         time = ceil(span.time);
+         goto recalc;
+     }
      *fsec = time;
  #endif

***************
*** 1237,1244 ****
  #else
      span->time = (((tm->tm_hour * (double)MINS_PER_HOUR) +
                          tm->tm_min) * (double)SECS_PER_MINUTE) +
!                         tm->tm_sec;
!     span->time = JROUND(span->time + fsec);
  #endif

      return 0;
--- 1270,1276 ----
  #else
      span->time = (((tm->tm_hour * (double)MINS_PER_HOUR) +
                          tm->tm_min) * (double)SECS_PER_MINUTE) +
!                         tm->tm_sec + fsec;
  #endif

      return 0;
***************
*** 1266,1272 ****
      dt -= (tz * USECS_PER_SEC);
  #else
      dt -= tz;
-     dt = JROUND(dt);
  #endif
      return dt;
  }    /* dt2local() */
--- 1298,1303 ----
***************
*** 1901,1911 ****
                  (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                   errmsg("cannot subtract infinite timestamps")));

- #ifdef HAVE_INT64_TIMESTAMP
      result->time = dt1 - dt2;
- #else
-     result->time = JROUND(dt1 - dt2);
- #endif

      result->month = 0;
      result->day = 0;
--- 1932,1938 ----
***************
*** 2224,2234 ****

      result->month = span1->month + span2->month;
      result->day = span1->day + span2->day;
- #ifdef HAVE_INT64_TIMESTAMP
      result->time = span1->time + span2->time;
- #else
-     result->time = JROUND(span1->time + span2->time);
- #endif

      PG_RETURN_INTERVAL_P(result);
  }
--- 2251,2257 ----
***************
*** 2244,2254 ****

      result->month = span1->month - span2->month;
      result->day = span1->day - span2->day;
- #ifdef HAVE_INT64_TIMESTAMP
      result->time = span1->time - span2->time;
- #else
-     result->time = JROUND(span1->time - span2->time);
- #endif

      PG_RETURN_INTERVAL_P(result);
  }
--- 2267,2273 ----
***************
*** 2280,2286 ****
  #ifdef HAVE_INT64_TIMESTAMP
      result->time = rint(span->time * factor + day_remainder * USECS_PER_DAY);
  #else
!     result->time = JROUND(span->time * factor + day_remainder * SECS_PER_DAY);
  #endif

      result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
--- 2299,2305 ----
  #ifdef HAVE_INT64_TIMESTAMP
      result->time = rint(span->time * factor + day_remainder * USECS_PER_DAY);
  #else
!     result->time = span->time * factor + day_remainder * SECS_PER_DAY;
  #endif

      result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
***************
*** 2332,2338 ****
      result->time += rint(day_remainder * USECS_PER_DAY);
  #else
      result->time += day_remainder * SECS_PER_DAY;
-     result->time = JROUND(result->time);
  #endif

      result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
--- 2351,2356 ----
*** src/include/utils/date.h.orig    Fri Feb 25 11:13:29 2005
--- src/include/utils/date.h    Sat Oct  8 13:12:28 2005
***************
*** 60,65 ****
--- 60,69 ----

  #define MAX_TIME_PRECISION 10

+ /* round off to MAX_TIME_PRECISION decimal places */
+ #define TIME_PREC_INV 10000000000.0
+ #define TIMEROUND(j) (rint(((double) (j)) * TIME_PREC_INV) / TIME_PREC_INV)
+
  #define DatumGetDateADT(X)      ((DateADT) DatumGetInt32(X))
  #define DatumGetTimeADT(X)      ((TimeADT) DatumGetFloat8(X))
  #define DatumGetTimeTzADTP(X) ((TimeTzADT *) DatumGetPointer(X))
*** src/include/utils/timestamp.h.orig    Sat Oct  8 10:52:07 2005
--- src/include/utils/timestamp.h    Sat Oct  8 13:35:06 2005
***************
*** 163,170 ****

  typedef double fsec_t;

! #define TIME_PREC_INV 1000000.0
! #define JROUND(j) (rint(((double) (j)) * TIME_PREC_INV) / TIME_PREC_INV)
  #endif

  #define TIMESTAMP_MASK(b) (1 << (b))
--- 163,173 ----

  typedef double fsec_t;

! /* round off to MAX_TIMESTAMP_PRECISION decimal places */
! /* note: this is also used for rounding off intervals */
! #define TS_PREC_INV 1000000.0
! #define TSROUND(j) (rint(((double) (j)) * TS_PREC_INV) / TS_PREC_INV)
!
  #endif

  #define TIMESTAMP_MASK(b) (1 << (b))