Introduce experimental time_bucket_ng() function

sql/CMakeLists.txt

@@ -37,6 +37,7 @@ set(SOURCE_FILES
     ddl_triggers.sql
     bookend.sql
     time_bucket.sql
+    time_bucket_ng.sql
     version.sql
     size_utils.sql
     histogram.sql

sql/time_bucket_ng.sql

@@ -0,0 +1,29 @@
+-- This file and its contents are licensed under the Apache License 2.0.
+-- Please see the included NOTICE for copyright information and
+-- LICENSE-APACHE for a copy of the license.
+
+-- time_bucket_ng() is an _experimental_ new version of time_bucket().
+--
+-- Unlike time_bucket(), time_bucket_ng() supports variable-sized buckets,
+-- such as months and years, and also timezones. Note that the behavior
+-- and the interface of this function are subjects to change. There could
+-- be bugs, and the implementation doesn't claim to be complete. Use at
+-- your own risk.
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts DATE) RETURNS DATE
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng' LANGUAGE C STABLE PARALLEL SAFE STRICT;
+
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts DATE, origin DATE) RETURNS DATE
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng' LANGUAGE C STABLE PARALLEL SAFE STRICT;
+
+-- utility functions
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts TIMESTAMP) RETURNS TIMESTAMP
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng_timestamp' LANGUAGE C STABLE PARALLEL SAFE STRICT;
+
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts TIMESTAMP, origin TIMESTAMP) RETURNS TIMESTAMP
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng_timestamp' LANGUAGE C STABLE PARALLEL SAFE STRICT;
+
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts TIMESTAMPTZ) RETURNS TIMESTAMPTZ
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng_timestamptz' LANGUAGE C STABLE PARALLEL SAFE STRICT;
+
+CREATE OR REPLACE FUNCTION timescaledb_experimental.time_bucket_ng(bucket_width INTERVAL, ts TIMESTAMPTZ, origin TIMESTAMPTZ) RETURNS TIMESTAMPTZ
+	AS '@MODULE_PATHNAME@', 'ts_time_bucket_ng_timestamptz' LANGUAGE C STABLE PARALLEL SAFE STRICT;

src/CMakeLists.txt

@@ -48,6 +48,7 @@ set(SOURCES
     subspace_store.c
     tablespace.c
     time_bucket.c
+    time_bucket_ng.c
     time_utils.c
     custom_type_cache.c
     trigger.c

src/time_bucket_ng.c

@@ -0,0 +1,152 @@
+/*
+ * This file and its contents are licensed under the Apache License 2.0.
+ * Please see the included NOTICE for copyright information and
+ * LICENSE-APACHE for a copy of the license.
+ */
+#include <postgres.h>
+#include <utils/date.h>
+#include <utils/datetime.h>
+#include <utils/fmgrprotos.h>
+
+#include "time_bucket_ng.h"
+
+TS_FUNCTION_INFO_V1(ts_time_bucket_ng);
+TS_FUNCTION_INFO_V1(ts_time_bucket_ng_timestamp);
+TS_FUNCTION_INFO_V1(ts_time_bucket_ng_timestamptz);
+
+TSDLLEXPORT Datum
+ts_time_bucket_ng_timestamp(PG_FUNCTION_ARGS)
+{
+	DateADT result;
+	Datum interval = PG_GETARG_DATUM(0);
+	DateADT ts_date = DatumGetDateADT(DirectFunctionCall1(timestamp_date, PG_GETARG_DATUM(1)));
+
+	if (PG_NARGS() > 2)
+	{
+		DateADT origin = DatumGetDateADT(DirectFunctionCall1(timestamp_date, PG_GETARG_DATUM(2)));
+		result = DatumGetDateADT(DirectFunctionCall3(ts_time_bucket_ng,
+													 interval,
+													 DateADTGetDatum(ts_date),
+													 DateADTGetDatum(origin)));
+	}
+	else
+	{
+		result = DatumGetDateADT(
+			DirectFunctionCall2(ts_time_bucket_ng, interval, DateADTGetDatum(ts_date)));
+	}
+
+	return DirectFunctionCall1(date_timestamp, DateADTGetDatum(result));
+}
+
+TSDLLEXPORT Datum
+ts_time_bucket_ng_timestamptz(PG_FUNCTION_ARGS)
+{
+	DateADT result;
+	Datum interval = PG_GETARG_DATUM(0);
+	DateADT ts_date = DatumGetDateADT(DirectFunctionCall1(timestamptz_date, PG_GETARG_DATUM(1)));
+
+	if (PG_NARGS() > 2)
+	{
+		DateADT origin = DatumGetDateADT(DirectFunctionCall1(timestamptz_date, PG_GETARG_DATUM(2)));
+		result = DatumGetDateADT(DirectFunctionCall3(ts_time_bucket_ng,
+													 interval,
+													 DateADTGetDatum(ts_date),
+													 DateADTGetDatum(origin)));
+	}
+	else
+	{
+		result = DatumGetDateADT(
+			DirectFunctionCall2(ts_time_bucket_ng, interval, DateADTGetDatum(ts_date)));
+	}
+
+	return DirectFunctionCall1(date_timestamptz, DateADTGetDatum(result));
+}
+
+TSDLLEXPORT Datum
+ts_time_bucket_ng(PG_FUNCTION_ARGS)
+{
+	Interval *interval = PG_GETARG_INTERVAL_P(0);
+	DateADT date = PG_GETARG_DATEADT(1);
+	DateADT origin_date = 0; // 2000-01-01
+	int origin_year = 2000, origin_month = 1, origin_day = 1;
+	int year, month, day;
+	int delta, bucket_number;
+
+	if ((interval->time != 0) || ((interval->month != 0) && (interval->day != 0)))
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("interval must be either days and weeks, or months and years")));
+	}
+
+	if ((interval->month == 0) && (interval->day == 0))
+	{
+		/*
+		 * This will be fixed in future versions of ts_time_bucket_ng().
+		 * The reason why it's not yet implemented is that we want to start
+		 * experimenting with variable-sized buckets as soon as possible.
+		 * We know that fixed-sized buckets work OK and adding corresponding
+		 * logic will be trivial.
+		 */
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("interval must be at least one day")));
+	}
+
+	if (PG_NARGS() > 2)
+	{
+		origin_date = PG_GETARG_DATUM(2);
+		j2date(origin_date + POSTGRES_EPOCH_JDATE, &origin_year, &origin_month, &origin_day);
+	}
+
+	if ((origin_day != 1) && (interval->month != 0))
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("origin must be the first day of the month")));
+	}
+
+	if (DATE_NOT_FINITE(date))
+		PG_RETURN_DATEADT(date);
+
+	if (interval->month != 0)
+	{
+		/* Handle months and years */
+
+		j2date(date + POSTGRES_EPOCH_JDATE, &year, &month, &day);
+
+		if ((year < origin_year) || ((year == origin_year) && (month < origin_month)))
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("origin must be before the given date")));
+		}
+
+		delta = (year * 12 + month) - (origin_year * 12 + origin_month);
+		bucket_number = delta / interval->month;
+		year = origin_year + (bucket_number * interval->month) / 12;
+		month =
+			(((origin_year * 12 + (origin_month - 1)) + (bucket_number * interval->month)) % 12) +
+			1;
+		day = 1;
+
+		date = date2j(year, month, day) - POSTGRES_EPOCH_JDATE;
+	}
+	else
+	{
+		/* Handle days and weeks */
+
+		if (date < origin_date)
+		{
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("origin must be before the given date")));
+		}
+
+		delta = date - origin_date;
+		bucket_number = delta / interval->day;
+		date = bucket_number * interval->day;
+	}
+
+	PG_RETURN_DATEADT(date);
+}

src/time_bucket_ng.h

@@ -0,0 +1,18 @@
+/*
+ * This file and its contents are licensed under the Apache License 2.0.
+ * Please see the included NOTICE for copyright information and
+ * LICENSE-APACHE for a copy of the license.
+ */
+#ifndef TIMESCALEDB_DATE_TRUNC_H
+#define TIMESCALEDB_DATE_TRUNC_H
+
+#include <postgres.h>
+#include <fmgr.h>
+
+#include "export.h"
+
+extern TSDLLEXPORT Datum ts_time_bucket_ng(PG_FUNCTION_ARGS);
+extern TSDLLEXPORT Datum ts_time_bucket_ng_timestamp(PG_FUNCTION_ARGS);
+extern TSDLLEXPORT Datum ts_time_bucket_ng_timestamptz(PG_FUNCTION_ARGS);
+
+#endif /* TIMESCALEDB_DATE_TRUNC_H */