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Handle DST changes in gapfill
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This change makes gapfill calculate timezone offsets like
we do in time_bucket when there is a supplied timezone.
Without this, timezones would not align and we get timestamp
mismatches which cause double entries for a single bucket.
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@antekresic
antekresic committed Jan 9, 2024
1 parent 58859cb commit 3b9895c
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Showing 7 changed files with 106 additions and 16 deletions.
3 changes: 3 additions & 0 deletions .unreleased/fix_6507
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@@ -0,0 +1,3 @@
Fixes: #6344 time_bucket_gapfill with timezones doesn't handle daylight savings

Thanks: @JerkoNikolic Thanks for reporting the issue with gapfill and DST
30 changes: 26 additions & 4 deletions tsl/src/nodes/gapfill/gapfill_exec.c
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Expand Up @@ -656,10 +656,32 @@ gapfill_advance_timestamp(GapFillState *state)
* To be consistent with time_bucket we do UTC bucketing unless
* a different timezone got explicity passed to the function.
*/
next = DirectFunctionCall2(state->have_timezone ? timestamptz_pl_interval :
timestamp_pl_interval,
TimestampTzGetDatum(state->gapfill_start),
IntervalPGetDatum(state->next_offset));
if (state->have_timezone)
{
bool isnull;
/* TODO: optimize by constifying and caching the datum if possible */
Datum tzname = gapfill_exec_expr(state, get_timezone_arg(state), &isnull);
Assert(!isnull);

/* Convert to local timestamp */
next = DirectFunctionCall2(timestamptz_zone,
tzname,
TimestampTzGetDatum(state->gapfill_start));

/* Add interval */
next = DirectFunctionCall2(timestamp_pl_interval,
next,
IntervalPGetDatum(state->next_offset));

/* Convert back to specified timezone */
next = DirectFunctionCall2(timestamp_zone, tzname, next);
}
else
{
next = DirectFunctionCall2(timestamp_pl_interval,
TimestampTzGetDatum(state->gapfill_start),
IntervalPGetDatum(state->next_offset));
}
state->next_timestamp = DatumGetTimestampTz(next);
break;
default:
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21 changes: 18 additions & 3 deletions tsl/test/shared/expected/gapfill-13.out
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Expand Up @@ -3315,9 +3315,9 @@ SELECT time_bucket_gapfill('2 month'::interval, ts, 'UTC', '2000-01-01','2001-01
time_bucket_gapfill
Fri Dec 31 16:00:00 1999 PST
Tue Feb 29 16:00:00 2000 PST
Sun Apr 30 16:00:00 2000 PDT
Fri Jun 30 16:00:00 2000 PDT
Thu Aug 31 16:00:00 2000 PDT
Sun Apr 30 17:00:00 2000 PDT
Fri Jun 30 17:00:00 2000 PDT
Thu Aug 31 17:00:00 2000 PDT
Tue Oct 31 16:00:00 2000 PST
Sun Dec 31 16:00:00 2000 PST
(7 rows)
Expand Down Expand Up @@ -3391,6 +3391,21 @@ GROUP BY 1;
Fri Jun 30 15:00:00 2023 PDT |
(7 rows)

-- Test gapfill respects DST changes when generating timestamps (#6344)
SELECT time_bucket_gapfill('1 month', time, 'awst','2023-01-01', '2023-07-01' ) AS month, sum(value) AS sum
FROM month_timezone
GROUP BY 1;
month | sum
------------------------------+-------
Sat Dec 31 08:00:00 2022 PST |
Tue Jan 31 08:00:00 2023 PST |
Tue Feb 28 08:00:00 2023 PST | 3.123
Fri Mar 31 09:00:00 2023 PDT | 4.123
Sun Apr 30 09:00:00 2023 PDT | 5.123
Wed May 31 09:00:00 2023 PDT |
Fri Jun 30 09:00:00 2023 PDT |
(7 rows)

DROP TABLE month_timezone;
-- Test gapfill with additional group pathkeys added for optimization (#6396)
CREATE TABLE stocks_real_time (
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21 changes: 18 additions & 3 deletions tsl/test/shared/expected/gapfill-14.out
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Expand Up @@ -3315,9 +3315,9 @@ SELECT time_bucket_gapfill('2 month'::interval, ts, 'UTC', '2000-01-01','2001-01
time_bucket_gapfill
Fri Dec 31 16:00:00 1999 PST
Tue Feb 29 16:00:00 2000 PST
Sun Apr 30 16:00:00 2000 PDT
Fri Jun 30 16:00:00 2000 PDT
Thu Aug 31 16:00:00 2000 PDT
Sun Apr 30 17:00:00 2000 PDT
Fri Jun 30 17:00:00 2000 PDT
Thu Aug 31 17:00:00 2000 PDT
Tue Oct 31 16:00:00 2000 PST
Sun Dec 31 16:00:00 2000 PST
(7 rows)
Expand Down Expand Up @@ -3391,6 +3391,21 @@ GROUP BY 1;
Fri Jun 30 15:00:00 2023 PDT |
(7 rows)

-- Test gapfill respects DST changes when generating timestamps (#6344)
SELECT time_bucket_gapfill('1 month', time, 'awst','2023-01-01', '2023-07-01' ) AS month, sum(value) AS sum
FROM month_timezone
GROUP BY 1;
month | sum
------------------------------+-------
Sat Dec 31 08:00:00 2022 PST |
Tue Jan 31 08:00:00 2023 PST |
Tue Feb 28 08:00:00 2023 PST | 3.123
Fri Mar 31 09:00:00 2023 PDT | 4.123
Sun Apr 30 09:00:00 2023 PDT | 5.123
Wed May 31 09:00:00 2023 PDT |
Fri Jun 30 09:00:00 2023 PDT |
(7 rows)

DROP TABLE month_timezone;
-- Test gapfill with additional group pathkeys added for optimization (#6396)
CREATE TABLE stocks_real_time (
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21 changes: 18 additions & 3 deletions tsl/test/shared/expected/gapfill-15.out
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Expand Up @@ -3315,9 +3315,9 @@ SELECT time_bucket_gapfill('2 month'::interval, ts, 'UTC', '2000-01-01','2001-01
time_bucket_gapfill
Fri Dec 31 16:00:00 1999 PST
Tue Feb 29 16:00:00 2000 PST
Sun Apr 30 16:00:00 2000 PDT
Fri Jun 30 16:00:00 2000 PDT
Thu Aug 31 16:00:00 2000 PDT
Sun Apr 30 17:00:00 2000 PDT
Fri Jun 30 17:00:00 2000 PDT
Thu Aug 31 17:00:00 2000 PDT
Tue Oct 31 16:00:00 2000 PST
Sun Dec 31 16:00:00 2000 PST
(7 rows)
Expand Down Expand Up @@ -3391,6 +3391,21 @@ GROUP BY 1;
Fri Jun 30 15:00:00 2023 PDT |
(7 rows)

-- Test gapfill respects DST changes when generating timestamps (#6344)
SELECT time_bucket_gapfill('1 month', time, 'awst','2023-01-01', '2023-07-01' ) AS month, sum(value) AS sum
FROM month_timezone
GROUP BY 1;
month | sum
------------------------------+-------
Sat Dec 31 08:00:00 2022 PST |
Tue Jan 31 08:00:00 2023 PST |
Tue Feb 28 08:00:00 2023 PST | 3.123
Fri Mar 31 09:00:00 2023 PDT | 4.123
Sun Apr 30 09:00:00 2023 PDT | 5.123
Wed May 31 09:00:00 2023 PDT |
Fri Jun 30 09:00:00 2023 PDT |
(7 rows)

DROP TABLE month_timezone;
-- Test gapfill with additional group pathkeys added for optimization (#6396)
CREATE TABLE stocks_real_time (
Expand Down
21 changes: 18 additions & 3 deletions tsl/test/shared/expected/gapfill-16.out
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Expand Up @@ -3317,9 +3317,9 @@ SELECT time_bucket_gapfill('2 month'::interval, ts, 'UTC', '2000-01-01','2001-01
time_bucket_gapfill
Fri Dec 31 16:00:00 1999 PST
Tue Feb 29 16:00:00 2000 PST
Sun Apr 30 16:00:00 2000 PDT
Fri Jun 30 16:00:00 2000 PDT
Thu Aug 31 16:00:00 2000 PDT
Sun Apr 30 17:00:00 2000 PDT
Fri Jun 30 17:00:00 2000 PDT
Thu Aug 31 17:00:00 2000 PDT
Tue Oct 31 16:00:00 2000 PST
Sun Dec 31 16:00:00 2000 PST
(7 rows)
Expand Down Expand Up @@ -3393,6 +3393,21 @@ GROUP BY 1;
Fri Jun 30 15:00:00 2023 PDT |
(7 rows)

-- Test gapfill respects DST changes when generating timestamps (#6344)
SELECT time_bucket_gapfill('1 month', time, 'awst','2023-01-01', '2023-07-01' ) AS month, sum(value) AS sum
FROM month_timezone
GROUP BY 1;
month | sum
------------------------------+-------
Sat Dec 31 08:00:00 2022 PST |
Tue Jan 31 08:00:00 2023 PST |
Tue Feb 28 08:00:00 2023 PST | 3.123
Fri Mar 31 09:00:00 2023 PDT | 4.123
Sun Apr 30 09:00:00 2023 PDT | 5.123
Wed May 31 09:00:00 2023 PDT |
Fri Jun 30 09:00:00 2023 PDT |
(7 rows)

DROP TABLE month_timezone;
-- Test gapfill with additional group pathkeys added for optimization (#6396)
CREATE TABLE stocks_real_time (
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5 changes: 5 additions & 0 deletions tsl/test/shared/sql/gapfill.sql.in
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Expand Up @@ -1536,6 +1536,11 @@ FROM
month_timezone
GROUP BY 1;

-- Test gapfill respects DST changes when generating timestamps (#6344)
SELECT time_bucket_gapfill('1 month', time, 'awst','2023-01-01', '2023-07-01' ) AS month, sum(value) AS sum
FROM month_timezone
GROUP BY 1;

DROP TABLE month_timezone;

-- Test gapfill with additional group pathkeys added for optimization (#6396)
Expand Down

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