Add cross-type comparisons for datetime types.

Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us

Author: tglsfdc

contrib/btree_gin/btree_gin--1.3--1.4.sql

@@ -101,3 +101,51 @@ ADD
     OPERATOR        12      >= (name, text),
     OPERATOR        13      > (name, text)
 ;
+
+ALTER OPERATOR FAMILY date_ops USING gin
+ADD
+    -- Code 1: RHS is timestamp
+    OPERATOR        9       < (date, timestamp),
+    OPERATOR        10      <= (date, timestamp),
+    OPERATOR        11      = (date, timestamp),
+    OPERATOR        12      >= (date, timestamp),
+    OPERATOR        13      > (date, timestamp),
+    -- Code 2: RHS is timestamptz
+    OPERATOR        17      < (date, timestamptz),
+    OPERATOR        18      <= (date, timestamptz),
+    OPERATOR        19      = (date, timestamptz),
+    OPERATOR        20      >= (date, timestamptz),
+    OPERATOR        21      > (date, timestamptz)
+;
+
+ALTER OPERATOR FAMILY timestamp_ops USING gin
+ADD
+    -- Code 1: RHS is date
+    OPERATOR        9       < (timestamp, date),
+    OPERATOR        10      <= (timestamp, date),
+    OPERATOR        11      = (timestamp, date),
+    OPERATOR        12      >= (timestamp, date),
+    OPERATOR        13      > (timestamp, date),
+    -- Code 2: RHS is timestamptz
+    OPERATOR        17      < (timestamp, timestamptz),
+    OPERATOR        18      <= (timestamp, timestamptz),
+    OPERATOR        19      = (timestamp, timestamptz),
+    OPERATOR        20      >= (timestamp, timestamptz),
+    OPERATOR        21      > (timestamp, timestamptz)
+;
+
+ALTER OPERATOR FAMILY timestamptz_ops USING gin
+ADD
+    -- Code 1: RHS is date
+    OPERATOR        9       < (timestamptz, date),
+    OPERATOR        10      <= (timestamptz, date),
+    OPERATOR        11      = (timestamptz, date),
+    OPERATOR        12      >= (timestamptz, date),
+    OPERATOR        13      > (timestamptz, date),
+    -- Code 2: RHS is timestamp
+    OPERATOR        17      < (timestamptz, timestamp),
+    OPERATOR        18      <= (timestamptz, timestamp),
+    OPERATOR        19      = (timestamptz, timestamp),
+    OPERATOR        20      >= (timestamptz, timestamp),
+    OPERATOR        21      > (timestamptz, timestamp)
+;

contrib/btree_gin/btree_gin.c

@@ -483,21 +483,75 @@ leftmostvalue_timestamp(void)
 	return TimestampGetDatum(DT_NOBEGIN);
 }
 
+static Datum
+cvt_date_timestamp(Datum input)
+{
+	DateADT		val = DatumGetDateADT(input);
+	Timestamp	result;
+	int			overflow;
+
+	result = date2timestamp_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return TimestampGetDatum(result);
+}
+
+static Datum
+cvt_timestamptz_timestamp(Datum input)
+{
+	TimestampTz val = DatumGetTimestampTz(input);
+	Timestamp	result;
+	int			overflow;
+
+	result = timestamptz2timestamp_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return TimestampGetDatum(result);
+}
+
 static const bool timestamp_rhs_is_varlena[] =
-{false};
+{false, false, false};
+
+static const btree_gin_convert_function timestamp_cvt_fns[] =
+{NULL, cvt_date_timestamp, cvt_timestamptz_timestamp};
 
 static const PGFunction timestamp_cmp_fns[] =
-{timestamp_cmp};
+{timestamp_cmp, date_cmp_timestamp, timestamptz_cmp_timestamp};
+
+GIN_SUPPORT(timestamp, leftmostvalue_timestamp, timestamp_rhs_is_varlena, timestamp_cvt_fns, timestamp_cmp_fns)
+
+static Datum
+cvt_date_timestamptz(Datum input)
+{
+	DateADT		val = DatumGetDateADT(input);
+	TimestampTz result;
+	int			overflow;
 
-GIN_SUPPORT(timestamp, leftmostvalue_timestamp, timestamp_rhs_is_varlena, NULL, timestamp_cmp_fns)
+	result = date2timestamptz_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return TimestampTzGetDatum(result);
+}
+
+static Datum
+cvt_timestamp_timestamptz(Datum input)
+{
+	Timestamp	val = DatumGetTimestamp(input);
+	TimestampTz result;
+	int			overflow;
+
+	result = timestamp2timestamptz_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return TimestampTzGetDatum(result);
+}
 
 static const bool timestamptz_rhs_is_varlena[] =
-{false};
+{false, false, false};
+
+static const btree_gin_convert_function timestamptz_cvt_fns[] =
+{NULL, cvt_date_timestamptz, cvt_timestamp_timestamptz};
 
 static const PGFunction timestamptz_cmp_fns[] =
-{timestamp_cmp};
+{timestamp_cmp, date_cmp_timestamptz, timestamp_cmp_timestamptz};
 
-GIN_SUPPORT(timestamptz, leftmostvalue_timestamp, timestamptz_rhs_is_varlena, NULL, timestamptz_cmp_fns)
+GIN_SUPPORT(timestamptz, leftmostvalue_timestamp, timestamptz_rhs_is_varlena, timestamptz_cvt_fns, timestamptz_cmp_fns)
 
 static Datum
 leftmostvalue_time(void)
@@ -538,13 +592,40 @@ leftmostvalue_date(void)
 	return DateADTGetDatum(DATEVAL_NOBEGIN);
 }
 
+static Datum
+cvt_timestamp_date(Datum input)
+{
+	Timestamp	val = DatumGetTimestamp(input);
+	DateADT		result;
+	int			overflow;
+
+	result = timestamp2date_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return DateADTGetDatum(result);
+}
+
+static Datum
+cvt_timestamptz_date(Datum input)
+{
+	TimestampTz val = DatumGetTimestampTz(input);
+	DateADT		result;
+	int			overflow;
+
+	result = timestamptz2date_opt_overflow(val, &overflow);
+	/* We can ignore the overflow result, since result is useful as-is */
+	return DateADTGetDatum(result);
+}
+
 static const bool date_rhs_is_varlena[] =
-{false};
+{false, false, false};
+
+static const btree_gin_convert_function date_cvt_fns[] =
+{NULL, cvt_timestamp_date, cvt_timestamptz_date};
 
 static const PGFunction date_cmp_fns[] =
-{date_cmp};
+{date_cmp, timestamp_cmp_date, timestamptz_cmp_date};
 
-GIN_SUPPORT(date, leftmostvalue_date, date_rhs_is_varlena, NULL, date_cmp_fns)
+GIN_SUPPORT(date, leftmostvalue_date, date_rhs_is_varlena, date_cvt_fns, date_cmp_fns)
 
 static Datum
 leftmostvalue_interval(void)