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| author | Peter Eisentraut <peter@eisentraut.org> | 2022-04-19 20:38:53 +0200 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2022-04-19 21:03:27 +0200 |
| commit | 7a8d8219ccbf0963f2171ea23e1616ee6a7823ba (patch) | |
| tree | 78791deb152604edbf8826046fe3ce1d1430e58c /src/backend/utils/adt/timestamp.c | |
| parent | c9dea58e270236a8d256a686f71f6bab960f0b80 (diff) | |
| download | postgresql-7a8d8219ccbf0963f2171ea23e1616ee6a7823ba.tar.gz postgresql-7a8d8219ccbf0963f2171ea23e1616ee6a7823ba.zip | |
Fix extract epoch from interval calculation
The new numeric code for extract epoch from interval accidentally
truncated the DAYS_PER_YEAR value to an integer, leading to results
that mismatched the floating-point interval_part calculations.
The commit a2da77cdb4661826482ebf2ddba1f953bc74afe4 that introduced
this actually contains the regression test change that this reverts.
I suppose this was missed at the time.
Reported-by: Joseph Koshakow <koshy44@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/CAAvxfHd5n%3D13NYA2q_tUq%3D3%3DSuWU-CufmTf-Ozj%3DfrEgt7pXwQ%40mail.gmail.com
Diffstat (limited to 'src/backend/utils/adt/timestamp.c')
| -rw-r--r-- | src/backend/utils/adt/timestamp.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index 1c0bf0aa5c8..fbe3c29ee10 100644 --- a/src/backend/utils/adt/timestamp.c +++ b/src/backend/utils/adt/timestamp.c @@ -5287,10 +5287,16 @@ interval_part_common(PG_FUNCTION_ARGS, bool retnumeric) int64 secs_from_day_month; int64 val; - /* this always fits into int64 */ - secs_from_day_month = ((int64) DAYS_PER_YEAR * (interval->month / MONTHS_PER_YEAR) + - (int64) DAYS_PER_MONTH * (interval->month % MONTHS_PER_YEAR) + - interval->day) * SECS_PER_DAY; + /* + * To do this calculation in integer arithmetic even though + * DAYS_PER_YEAR is fractional, multiply everything by 4 and then + * divide by 4 again at the end. This relies on DAYS_PER_YEAR + * being a multiple of 0.25 and on SECS_PER_DAY being a multiple + * of 4. + */ + secs_from_day_month = ((int64) (4 * DAYS_PER_YEAR) * (interval->month / MONTHS_PER_YEAR) + + (int64) (4 * DAYS_PER_MONTH) * (interval->month % MONTHS_PER_YEAR) + + (int64) 4 * interval->day) * (SECS_PER_DAY / 4); /*--- * result = secs_from_day_month + interval->time / 1'000'000 |