Add comment documenting actual failure case of using

interval_justify_hours in timestamp subtraction.  TODO already has text
description.
This commit is contained in:
Bruce Momjian 2005-10-27 02:45:22 +00:00
parent 807da29cf3
commit 69f16b562a

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.156 2005/10/25 17:13:07 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.157 2005/10/27 02:45:22 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -1943,8 +1943,31 @@ timestamp_mi(PG_FUNCTION_ARGS)
result->month = 0;
result->day = 0;
/* this is wrong, but removing it breaks a lot of regression tests */
result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
/*
* This is wrong, but removing it breaks a lot of regression tests.
* For example:
*
* test=> SET timezone = 'EST5EDT';
* test=> SELECT
* test-> ('2005-10-30 13:22:00-05'::timestamptz -
* test(> '2005-10-29 13:22:00-04'::timestamptz);
* ?column?
* ----------------
* 1 day 01:00:00
* (1 row)
*
* so adding that to the first timestamp gets:
*
* test=> SELECT
* test-> ('2005-10-29 13:22:00-04'::timestamptz +
* test(> ('2005-10-30 13:22:00-05'::timestamptz -
* test(> '2005-10-29 13:22:00-04'::timestamptz)) at time zone 'EST';
* timezone
* --------------------
* 2005-10-30 14:22:00
* (1 row)
*/
result = DatumGetIntervalP(DirectFunctionCall1(interval_justify_hours,
IntervalPGetDatum(result)));
PG_RETURN_INTERVAL_P(result);