Support for FF1-FF6 datetime format patterns

SQL Standard 2016 defines FF1-FF9 format patters for fractions of seconds in
jsonpath .datetime() method and CAST (... FORMAT ...) SQL clause.  Parsing
engine of upcoming .datetime() method will be shared with to_date()/
to_timestamp().

This patch implements FF1-FF6 format patterns for upcoming jsonpath .datetime()
method.  to_date()/to_timestamp() functions will also get support of this
format patterns as positive side effect.  FF7-FF9 are not supported due to
lack of precision in our internal timestamp representation.

Extracted from original patch by Nikita Glukhov, Teodor Sigaev, Oleg Bartunov.
Heavily revised by me.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov
Reviewed-by: Anastasia Lubennikova, Peter Eisentraut

doc/src/sgml/func.sgml

@@ -6150,6 +6150,30 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
         <entry><literal>US</literal></entry>
         <entry>microsecond (000000-999999)</entry>
        </row>
+       <row>
+        <entry><literal>FF1</literal></entry>
+        <entry>tenth of second (0-9)</entry>
+       </row>
+       <row>
+        <entry><literal>FF2</literal></entry>
+        <entry>hundredth of second (00-99)</entry>
+       </row>
+       <row>
+        <entry><literal>FF3</literal></entry>
+        <entry>millisecond (000-999)</entry>
+       </row>
+       <row>
+        <entry><literal>FF4</literal></entry>
+        <entry>tenth of a millisecond (0000-9999)</entry>
+       </row>
+       <row>
+        <entry><literal>FF5</literal></entry>
+        <entry>hundredth of a millisecond (00000-99999)</entry>
+       </row>
+       <row>
+        <entry><literal>FF6</literal></entry>
+        <entry>microsecond (000000-999999)</entry>
+       </row>
        <row>
         <entry><literal>SSSS</literal></entry>
         <entry>seconds past midnight (0-86399)</entry>

src/backend/utils/adt/formatting.c

@@ -86,6 +86,7 @@
 #endif
 
 #include "catalog/pg_collation.h"
+#include "catalog/pg_type.h"
 #include "mb/pg_wchar.h"
 #include "utils/builtins.h"
 #include "utils/date.h"
@@ -434,7 +435,8 @@ typedef struct
 				clock,			/* 12 or 24 hour clock? */
 				tzsign,			/* +1, -1 or 0 if timezone info is absent */
 				tzh,
-				tzm;
+				tzm,
+				ff;				/* fractional precision */
 } TmFromChar;
 
 #define ZERO_tmfc(_X) memset(_X, 0, sizeof(TmFromChar))
@@ -594,6 +596,12 @@ typedef enum
 	DCH_Day,
 	DCH_Dy,
 	DCH_D,
+	DCH_FF1,
+	DCH_FF2,
+	DCH_FF3,
+	DCH_FF4,
+	DCH_FF5,
+	DCH_FF6,
 	DCH_FX,						/* global suffix */
 	DCH_HH24,
 	DCH_HH12,
@@ -643,6 +651,12 @@ typedef enum
 	DCH_dd,
 	DCH_dy,
 	DCH_d,
+	DCH_ff1,
+	DCH_ff2,
+	DCH_ff3,
+	DCH_ff4,
+	DCH_ff5,
+	DCH_ff6,
 	DCH_fx,
 	DCH_hh24,
 	DCH_hh12,
@@ -743,7 +757,13 @@ static const KeyWord DCH_keywords[] = {
 	{"Day", 3, DCH_Day, false, FROM_CHAR_DATE_NONE},
 	{"Dy", 2, DCH_Dy, false, FROM_CHAR_DATE_NONE},
 	{"D", 1, DCH_D, true, FROM_CHAR_DATE_GREGORIAN},
-	{"FX", 2, DCH_FX, false, FROM_CHAR_DATE_NONE},	/* F */
+	{"FF1", 3, DCH_FF1, false, FROM_CHAR_DATE_NONE},	/* F */
+	{"FF2", 3, DCH_FF2, false, FROM_CHAR_DATE_NONE},
+	{"FF3", 3, DCH_FF3, false, FROM_CHAR_DATE_NONE},
+	{"FF4", 3, DCH_FF4, false, FROM_CHAR_DATE_NONE},
+	{"FF5", 3, DCH_FF5, false, FROM_CHAR_DATE_NONE},
+	{"FF6", 3, DCH_FF6, false, FROM_CHAR_DATE_NONE},
+	{"FX", 2, DCH_FX, false, FROM_CHAR_DATE_NONE},
 	{"HH24", 4, DCH_HH24, true, FROM_CHAR_DATE_NONE},	/* H */
 	{"HH12", 4, DCH_HH12, true, FROM_CHAR_DATE_NONE},
 	{"HH", 2, DCH_HH, true, FROM_CHAR_DATE_NONE},
@@ -792,7 +812,13 @@ static const KeyWord DCH_keywords[] = {
 	{"dd", 2, DCH_DD, true, FROM_CHAR_DATE_GREGORIAN},
 	{"dy", 2, DCH_dy, false, FROM_CHAR_DATE_NONE},
 	{"d", 1, DCH_D, true, FROM_CHAR_DATE_GREGORIAN},
-	{"fx", 2, DCH_FX, false, FROM_CHAR_DATE_NONE},	/* f */
+	{"ff1", 3, DCH_FF1, false, FROM_CHAR_DATE_NONE},	/* f */
+	{"ff2", 3, DCH_FF2, false, FROM_CHAR_DATE_NONE},
+	{"ff3", 3, DCH_FF3, false, FROM_CHAR_DATE_NONE},
+	{"ff4", 3, DCH_FF4, false, FROM_CHAR_DATE_NONE},
+	{"ff5", 3, DCH_FF5, false, FROM_CHAR_DATE_NONE},
+	{"ff6", 3, DCH_FF6, false, FROM_CHAR_DATE_NONE},
+	{"fx", 2, DCH_FX, false, FROM_CHAR_DATE_NONE},
 	{"hh24", 4, DCH_HH24, true, FROM_CHAR_DATE_NONE},	/* h */
 	{"hh12", 4, DCH_HH12, true, FROM_CHAR_DATE_NONE},
 	{"hh", 2, DCH_HH, true, FROM_CHAR_DATE_NONE},
@@ -893,10 +919,10 @@ static const int DCH_index[KeyWord_INDEX_SIZE] = {
 	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 	-1, -1, -1, -1, -1, DCH_A_D, DCH_B_C, DCH_CC, DCH_DAY, -1,
-	DCH_FX, -1, DCH_HH24, DCH_IDDD, DCH_J, -1, -1, DCH_MI, -1, DCH_OF,
+	DCH_FF1, -1, DCH_HH24, DCH_IDDD, DCH_J, -1, -1, DCH_MI, -1, DCH_OF,
 	DCH_P_M, DCH_Q, DCH_RM, DCH_SSSS, DCH_TZH, DCH_US, -1, DCH_WW, -1, DCH_Y_YYY,
 	-1, -1, -1, -1, -1, -1, -1, DCH_a_d, DCH_b_c, DCH_cc,
-	DCH_day, -1, DCH_fx, -1, DCH_hh24, DCH_iddd, DCH_j, -1, -1, DCH_mi,
+	DCH_day, -1, DCH_ff1, -1, DCH_hh24, DCH_iddd, DCH_j, -1, -1, DCH_mi,
 	-1, -1, DCH_p_m, DCH_q, DCH_rm, DCH_ssss, DCH_tz, DCH_us, -1, DCH_ww,
 	-1, DCH_y_yyy, -1, -1, -1, -1
 
@@ -960,7 +986,6 @@ typedef struct NUMProc
 			   *L_currency_symbol;
 } NUMProc;
 
-
 /* ----------
  * Functions
  * ----------
@@ -993,7 +1018,7 @@ static int	from_char_parse_int(int *dest, char **src, FormatNode *node);
 static int	seq_search(char *name, const char *const *array, int type, int max, int *len);
 static int	from_char_seq_search(int *dest, char **src, const char *const *array, int type, int max, FormatNode *node);
 static void do_to_timestamp(text *date_txt, text *fmt,
-							struct pg_tm *tm, fsec_t *fsec);
+							struct pg_tm *tm, fsec_t *fsec, int *fprec);
 static char *fill_str(char *str, int c, int max);
 static FormatNode *NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree);
 static char *int_to_roman(int number);
@@ -2518,18 +2543,32 @@ DCH_to_char(FormatNode *node, bool is_interval, TmToChar *in, char *out, Oid col
 					str_numth(s, s, S_TH_TYPE(n->suffix));
 				s += strlen(s);
 				break;
-			case DCH_MS:		/* millisecond */
+#define DCH_to_char_fsec(frac_fmt, frac_val) \
-				sprintf(s, "%03d", (int) (in->fsec / INT64CONST(1000)));
+				sprintf(s, frac_fmt, (int) (frac_val)); \
-				if (S_THth(n->suffix))
+				if (S_THth(n->suffix)) \
-					str_numth(s, s, S_TH_TYPE(n->suffix));
+					str_numth(s, s, S_TH_TYPE(n->suffix)); \
 				s += strlen(s);
+			case DCH_FF1:		/* tenth of second */
+				DCH_to_char_fsec("%01d", in->fsec / 100000);
+				break;
+			case DCH_FF2:		/* hundredth of second */
+				DCH_to_char_fsec("%02d", in->fsec / 10000);
+				break;
+			case DCH_FF3:
+			case DCH_MS:		/* millisecond */
+				DCH_to_char_fsec("%03d", in->fsec / 1000);
 				break;
+			case DCH_FF4:		/* tenth of a millisecond */
+				DCH_to_char_fsec("%04d", in->fsec / 100);
+				break;
+			case DCH_FF5:		/* hundredth of a millisecond */
+				DCH_to_char_fsec("%05d", in->fsec / 10);
+				break;
+			case DCH_FF6:
 			case DCH_US:		/* microsecond */
-				sprintf(s, "%06d", (int) in->fsec);
+				DCH_to_char_fsec("%06d", in->fsec);
-				if (S_THth(n->suffix))
-					str_numth(s, s, S_TH_TYPE(n->suffix));
-				s += strlen(s);
 				break;
+#undef DCH_to_char_fsec
 			case DCH_SSSS:
 				sprintf(s, "%d", tm->tm_hour * SECS_PER_HOUR +
 						tm->tm_min * SECS_PER_MINUTE +
@@ -3154,8 +3193,18 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 
 				SKIP_THth(s, n->suffix);
 				break;
+			case DCH_FF1:
+			case DCH_FF2:
+			case DCH_FF3:
+			case DCH_FF4:
+			case DCH_FF5:
+			case DCH_FF6:
+				out->ff = n->key->id - DCH_FF1 + 1;
+				/* fall through */
 			case DCH_US:		/* microsecond */
-				len = from_char_parse_int_len(&out->us, &s, 6, n);
+				len = from_char_parse_int_len(&out->us, &s,
+											  n->key->id == DCH_US ? 6 :
+											  out->ff, n);
 
 				out->us *= len == 1 ? 100000 :
 					len == 2 ? 10000 :
@@ -3689,8 +3738,9 @@ to_timestamp(PG_FUNCTION_ARGS)
 	int			tz;
 	struct pg_tm tm;
 	fsec_t		fsec;
+	int			fprec;
 
-	do_to_timestamp(date_txt, fmt, &tm, &fsec);
+	do_to_timestamp(date_txt, fmt, &tm, &fsec, &fprec);
 
 	/* Use the specified time zone, if any. */
 	if (tm.tm_zone)
@@ -3708,6 +3758,10 @@ to_timestamp(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
 				 errmsg("timestamp out of range")));
 
+	/* Use the specified fractional precision, if any. */
+	if (fprec)
+		AdjustTimestampForTypmod(&result, fprec);
+
 	PG_RETURN_TIMESTAMP(result);
 }
 
@@ -3725,7 +3779,7 @@ to_date(PG_FUNCTION_ARGS)
 	struct pg_tm tm;
 	fsec_t		fsec;
 
-	do_to_timestamp(date_txt, fmt, &tm, &fsec);
+	do_to_timestamp(date_txt, fmt, &tm, &fsec, NULL);
 
 	/* Prevent overflow in Julian-day routines */
 	if (!IS_VALID_JULIAN(tm.tm_year, tm.tm_mon, tm.tm_mday))
@@ -3749,8 +3803,8 @@ to_date(PG_FUNCTION_ARGS)
 /*
  * do_to_timestamp: shared code for to_timestamp and to_date
  *
- * Parse the 'date_txt' according to 'fmt', return results as a struct pg_tm
+ * Parse the 'date_txt' according to 'fmt', return results as a struct pg_tm,
- * and fractional seconds.
+ * fractional seconds, and fractional precision.
  *
  * We parse 'fmt' into a list of FormatNodes, which is then passed to
  * DCH_from_char to populate a TmFromChar with the parsed contents of
@@ -3761,7 +3815,7 @@ to_date(PG_FUNCTION_ARGS)
  */
 static void
 do_to_timestamp(text *date_txt, text *fmt,
-				struct pg_tm *tm, fsec_t *fsec)
+				struct pg_tm *tm, fsec_t *fsec, int *fprec)
 {
 	FormatNode *format;
 	TmFromChar	tmfc;
@@ -3817,6 +3871,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 		DCH_from_char(format, date_str, &tmfc);
 
 		pfree(fmt_str);
+
 		if (!incache)
 			pfree(format);
 	}
@@ -3998,6 +4053,8 @@ do_to_timestamp(text *date_txt, text *fmt,
 		*fsec += tmfc.ms * 1000;
 	if (tmfc.us)
 		*fsec += tmfc.us;
+	if (fprec)
+		*fprec = tmfc.ff;		/* fractional precision, if specified */
 
 	/* Range-check date fields according to bit mask computed above */
 	if (fmask != 0)

src/backend/utils/adt/timestamp.c

@@ -70,7 +70,6 @@ typedef struct
 
 static TimeOffset time2t(const int hour, const int min, const int sec, const fsec_t fsec);
 static Timestamp dt2local(Timestamp dt, int timezone);
-static void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
 static void AdjustIntervalForTypmod(Interval *interval, int32 typmod);
 static TimestampTz timestamp2timestamptz(Timestamp timestamp);
 static Timestamp timestamptz2timestamp(TimestampTz timestamp);
@@ -333,7 +332,7 @@ timestamp_scale(PG_FUNCTION_ARGS)
  * AdjustTimestampForTypmod --- round off a timestamp to suit given typmod
  * Works for either timestamp or timestamptz.
  */
-static void
+void
 AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
 {
 	static const int64 TimestampScales[MAX_TIMESTAMP_PRECISION + 1] = {

src/include/utils/datetime.h

@@ -336,4 +336,6 @@ extern TimeZoneAbbrevTable *ConvertTimeZoneAbbrevs(struct tzEntry *abbrevs,
 												   int n);
 extern void InstallTimeZoneAbbrevs(TimeZoneAbbrevTable *tbl);
 
+extern void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
+
 #endif							/* DATETIME_H */

src/test/regress/expected/horology.out

@@ -2786,6 +2786,85 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
  Sun Dec 18 03:18:00 2011 PST
 (1 row)
 
+SELECT i, to_timestamp('2018-11-02 12:34:56', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |         to_timestamp         
+---+------------------------------
+ 1 | Fri Nov 02 12:34:56 2018 PDT
+ 2 | Fri Nov 02 12:34:56 2018 PDT
+ 3 | Fri Nov 02 12:34:56 2018 PDT
+ 4 | Fri Nov 02 12:34:56 2018 PDT
+ 5 | Fri Nov 02 12:34:56 2018 PDT
+ 6 | Fri Nov 02 12:34:56 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.1', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |          to_timestamp          
+---+--------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.1 2018 PDT
+ 3 | Fri Nov 02 12:34:56.1 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1 2018 PDT
+ 5 | Fri Nov 02 12:34:56.1 2018 PDT
+ 6 | Fri Nov 02 12:34:56.1 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.12', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |          to_timestamp           
+---+---------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.12 2018 PDT
+ 4 | Fri Nov 02 12:34:56.12 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12 2018 PDT
+ 6 | Fri Nov 02 12:34:56.12 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |           to_timestamp           
+---+----------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.123 2018 PDT
+ 5 | Fri Nov 02 12:34:56.123 2018 PDT
+ 6 | Fri Nov 02 12:34:56.123 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.1234', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |           to_timestamp            
+---+-----------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1234 2018 PDT
+ 5 | Fri Nov 02 12:34:56.1234 2018 PDT
+ 6 | Fri Nov 02 12:34:56.1234 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.12345', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |            to_timestamp            
+---+------------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1235 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12345 2018 PDT
+ 6 | Fri Nov 02 12:34:56.12345 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |            to_timestamp             
+---+-------------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1235 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12346 2018 PDT
+ 6 | Fri Nov 02 12:34:56.123456 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456789', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ERROR:  date/time field value out of range: "2018-11-02 12:34:56.123456789"
 --
 -- Check handling of multiple spaces in format and/or input
 --

src/test/regress/expected/timestamp.out

@@ -1584,6 +1584,21 @@ SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
             | 2001 1 1 1 1 1 1
 (65 rows)
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamp),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+ to_char_12 |                              to_char                               
+------------+--------------------------------------------------------------------
+            | 0 00 000 0000 00000 000000  0 00 000 0000 00000 000000  000 000000
+            | 7 78 780 7800 78000 780000  7 78 780 7800 78000 780000  780 780000
+            | 7 78 789 7890 78901 789010  7 78 789 7890 78901 789010  789 789010
+            | 7 78 789 7890 78901 789012  7 78 789 7890 78901 789012  789 789012
+(4 rows)
+
 -- timestamp numeric fields constructor
 SELECT make_timestamp(2014,12,28,6,30,45.887);
         make_timestamp        

src/test/regress/expected/timestamptz.out

@@ -1704,6 +1704,21 @@ SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
             | 2001 1 1 1 1 1 1
 (66 rows)
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamptz),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+ to_char_12 |                              to_char                               
+------------+--------------------------------------------------------------------
+            | 0 00 000 0000 00000 000000  0 00 000 0000 00000 000000  000 000000
+            | 7 78 780 7800 78000 780000  7 78 780 7800 78000 780000  780 780000
+            | 7 78 789 7890 78901 789010  7 78 789 7890 78901 789010  789 789010
+            | 7 78 789 7890 78901 789012  7 78 789 7890 78901 789012  789 789012
+(4 rows)
+
 -- Check OF, TZH, TZM with various zone offsets, particularly fractional hours
 SET timezone = '00:00';
 SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";

src/test/regress/sql/horology.sql

@@ -402,6 +402,15 @@ SELECT to_timestamp('2011-12-18 11:38 +05:20', 'YYYY-MM-DD HH12:MI TZH:TZM');
 SELECT to_timestamp('2011-12-18 11:38 -05:20', 'YYYY-MM-DD HH12:MI TZH:TZM');
 SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 
+SELECT i, to_timestamp('2018-11-02 12:34:56', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.1', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.12', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.1234', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.12345', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456789', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+
 --
 -- Check handling of multiple spaces in format and/or input
 --

src/test/regress/sql/timestamp.sql

@@ -224,5 +224,13 @@ SELECT '' AS to_char_10, to_char(d1, 'IYYY IYY IY I IW IDDD ID')
 SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
    FROM TIMESTAMP_TBL;
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamp),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+
 -- timestamp numeric fields constructor
 SELECT make_timestamp(2014,12,28,6,30,45.887);

src/test/regress/sql/timestamptz.sql

@@ -248,6 +248,14 @@ SELECT '' AS to_char_10, to_char(d1, 'IYYY IYY IY I IW IDDD ID')
 SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
    FROM TIMESTAMPTZ_TBL;
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamptz),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+
 -- Check OF, TZH, TZM with various zone offsets, particularly fractional hours
 SET timezone = '00:00';
 SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";