diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 698daf69ea..1c8541d552 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6166,7 +6166,8 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        <function>to_timestamp</function> and <function>to_date</function>
        skip multiple blank spaces in the input string unless the
        <literal>FX</literal> option is used. For example,
-       <literal>to_timestamp('2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> works, but
+       <literal>to_timestamp('2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000&nbsp;JUN', 'YYYY&nbsp;&nbsp;&nbsp;&nbsp;MON')</literal> work, but
        <literal>to_timestamp('2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'FXYYYY MON')</literal> returns an error
        because <function>to_timestamp</function> expects one space only.
        <literal>FX</literal> must be specified as the first item in
@@ -6174,6 +6175,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       <function>to_timestamp</function> and <function>to_date</function> don't
+       skip multiple printable non letter and non digit characters in the input
+       string, but skip them in the formatting string. For example,
+       <literal>to_timestamp('2000-JUN', 'YYYY/MON')</literal> and
+       <literal>to_timestamp('2000/JUN', 'YYYY//MON')</literal> work, but
+       <literal>to_timestamp('2000//JUN', 'YYYY/MON')</literal>
+       returns an error because count of the "/" character in the input string
+       doesn't match count of it in the formatting string.
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        Ordinary text is allowed in <function>to_char</function>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index ec97de0ad2..81565aab96 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -171,6 +171,8 @@ typedef struct
 #define NODE_TYPE_END		1
 #define NODE_TYPE_ACTION	2
 #define NODE_TYPE_CHAR		3
+#define NODE_TYPE_SEPARATOR	4
+#define NODE_TYPE_SPACE		5
 
 #define SUFFTYPE_PREFIX		1
 #define SUFFTYPE_POSTFIX	2
@@ -953,6 +955,7 @@ typedef struct NUMProc
 static const KeyWord *index_seq_search(const char *str, const KeyWord *kw,
 				 const int *index);
 static const KeySuffix *suff_search(const char *str, const KeySuffix *suf, int type);
+static bool is_separator_char(const char *str);
 static void NUMDesc_prepare(NUMDesc *num, FormatNode *n);
 static void parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 			 const KeySuffix *suf, const int *index, int ver, NUMDesc *Num);
@@ -969,7 +972,6 @@ static void dump_node(FormatNode *node, int max);
 static const char *get_th(char *num, int type);
 static char *str_numth(char *dest, char *num, int type);
 static int	adjust_partial_year_to_2020(int year);
-static int	strspace_len(char *str);
 static void from_char_set_mode(TmFromChar *tmfc, const FromCharDateMode mode);
 static void from_char_set_int(int *dest, const int value, const FormatNode *node);
 static int	from_char_parse_int_len(int *dest, char **src, const int len, FormatNode *node);
@@ -1042,6 +1044,16 @@ suff_search(const char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_separator_char(const char *str)
+{
+	/* ASCII printable character, but not letter or digit */
+	return (*str > 0x20 && *str < 0x7F &&
+			!(*str >= 'A' && *str <= 'Z') &&
+			!(*str >= 'a' && *str <= 'z') &&
+			!(*str >= '0' && *str <= '9'));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1317,7 +1329,14 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 				if (*str == '\\' && *(str + 1) == '"')
 					str++;
 				chlen = pg_mblen(str);
-				n->type = NODE_TYPE_CHAR;
+
+				if (ver == DCH_TYPE && is_separator_char(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace((unsigned char) *str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				memcpy(n->character, str, chlen);
 				n->character[chlen] = '\0';
 				n->key = NULL;
@@ -2115,19 +2134,6 @@ adjust_partial_year_to_2020(int year)
 }
 
 
-static int
-strspace_len(char *str)
-{
-	int			len = 0;
-
-	while (*str && isspace((unsigned char) *str))
-	{
-		str++;
-		len++;
-	}
-	return len;
-}
-
 /*
  * Set the date mode of a from-char conversion.
  *
@@ -2197,11 +2203,6 @@ from_char_parse_int_len(int *dest, char **src, const int len, FormatNode *node)
 	char	   *init = *src;
 	int			used;
 
-	/*
-	 * Skip any whitespace before parsing the integer.
-	 */
-	*src += strspace_len(*src);
-
 	Assert(len <= DCH_MAX_ITEM_SIZ);
 	used = (int) strlcpy(copy, *src, len + 1);
 
@@ -2975,17 +2976,60 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
+		{
+			/*
+			 * In non FX (fixed format) mode we don't insist that the consumed
+			 * character matches the format's character.
+			 */
+			if (!fx_mode)
+			{
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+					s++;
+
+				continue;
+			}
+
+			/*
+			 * In FX mode we insist that whitespace from the format string
+			 * matches whitespace from the input string.
+			 */
+			if (n->type == NODE_TYPE_SPACE && !isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
+			/*
+			 * In FX mode we insist that separator character from the format
+			 * string matches separator character from the input string.
+			 */
+			else if (n->type == NODE_TYPE_SEPARATOR && *n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
+
+			s++;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * Text character, so consume one character from input string.
+			 * Notice we don't insist that the consumed character match the
+			 * format's character.
+			 * Text field ignores FX mode.
 			 */
 			s += pg_mblen(s);
 			continue;
 		}
 
+		/* n->type == NODE_TYPE_ACTION */
+
 		/* Ignore spaces before fields when not in FX (fixed width) mode */
 		if (!fx_mode && n->key->id != DCH_FX)
 		{
@@ -2993,6 +3037,31 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				s++;
 		}
 
+		if (!fx_mode)
+		{
+			/*
+			 * Lost separator character from the input string. Separator
+			 * character should match at least one space or separator character
+			 * from the format string.
+			 */
+			if (is_separator_char(s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\"", *s),
+						 errhint("Separator character from the input string "
+								 "must match at least one space or separator "
+								 "character from the format string.")));
+		}
+		/*
+		 * In FX mode we don't expect a whitespace or a character.
+		 */
+		else if (isspace((unsigned char) *s) || is_separator_char(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errhint("In FX mode, punctuation in the input string "
+							 "must exactly match the format string.")));
+
 		from_char_set_mode(out, n->key->date_mode);
 
 		switch (n->key->id)
@@ -3232,6 +3301,13 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+				s++;
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 7b3d058425..54a42ee42e 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2769,14 +2769,32 @@ SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS');
  Sat Feb 16 08:14:30 0097 PST
 (1 row)
 
+SELECT to_timestamp('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS');
+         to_timestamp         
+------------------------------
+ Fri Mar 18 23:38:15 2011 PDT
+(1 row)
+
 SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD');
          to_timestamp         
 ------------------------------
  Sat Jan 12 00:00:00 1985 PST
 (1 row)
 
+SELECT to_timestamp('1985 FMMonth 12', 'YYYY "FMMonth" DD');
+         to_timestamp         
+------------------------------
+ Sat Jan 12 00:00:00 1985 PST
+(1 row)
+
+SELECT to_timestamp('1985 \ 12', 'YYYY \\ DD');
+         to_timestamp         
+------------------------------
+ Sat Jan 12 00:00:00 1985 PST
+(1 row)
+
 SELECT to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16',
-                    '"My birthday-> Year" YYYY, "Month:" FMMonth, "Day:" DD');
+                    '"My birthday-> Year:" YYYY, "Month:" FMMonth, "Day:" DD');
          to_timestamp         
 ------------------------------
  Sun May 16 00:00:00 1976 PDT
@@ -2789,7 +2807,7 @@ SELECT to_timestamp('1,582nd VIII 21', 'Y,YYYth FMRM DD');
 (1 row)
 
 SELECT to_timestamp('15 "text between quote marks" 98 54 45',
-                    E'HH24 "\\text between quote marks\\"" YY MI SS');
+                    E'HH24 "\\"text between quote marks\\"" YY MI SS');
          to_timestamp         
 ------------------------------
  Thu Jan 01 15:54:45 1998 PST
@@ -2808,8 +2826,23 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 (1 row)
 
 SELECT to_timestamp('97/Feb/16', 'YYMonDD');
-ERROR:  invalid value "/Fe" for "Mon"
-DETAIL:  The given value did not match any of the allowed values for this field.
+ERROR:  unexpected character "/"
+HINT:  Separator character from the input string must match at least one space or separator character from the format string.
+SELECT to_timestamp('97/Feb/16', 'YY:Mon:DD');
+         to_timestamp         
+------------------------------
+ Sun Feb 16 00:00:00 1997 PST
+(1 row)
+
+SELECT to_timestamp('97/Feb/16', 'FXYY:Mon:DD');
+ERROR:  unexpected character "/", expected ":"
+HINT:  In FX mode, punctuation in the input string must exactly match the format string.
+SELECT to_timestamp('97/Feb/16', 'FXYY/Mon/DD');
+         to_timestamp         
+------------------------------
+ Sun Feb 16 00:00:00 1997 PST
+(1 row)
+
 SELECT to_timestamp('19971116', 'YYYYMMDD');
          to_timestamp         
 ------------------------------
@@ -2936,7 +2969,7 @@ SELECT to_timestamp('2011-12-18 11:38 PM', 'YYYY-MM-DD HH12:MI PM');
 SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD  HH24:MI:SS');
          to_timestamp         
 ------------------------------
- Sun Dec 18 03:38:15 2011 PST
+ Sun Dec 18 23:38:15 2011 PST
 (1 row)
 
 SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD  HH24:MI:SS');
@@ -2966,9 +2999,33 @@ SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD  HH24:MI:SS');
 SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD   HH24:MI:SS');
          to_timestamp         
 ------------------------------
- Sun Dec 18 03:38:15 2011 PST
+ Sun Dec 18 23:38:15 2011 PST
 (1 row)
 
+SELECT to_timestamp('2000----JUN', 'YYYY MON');
+ERROR:  unexpected character "-"
+HINT:  Separator character from the input string must match at least one space or separator character from the format string.
+SELECT to_timestamp('2000 +   JUN', 'YYYY MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000 + + JUN', 'YYYY MON');
+ERROR:  unexpected character "+"
+HINT:  Separator character from the input string must match at least one space or separator character from the format string.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000--JUN', 'YYYY/MON');
+ERROR:  unexpected character "-"
+HINT:  Separator character from the input string must match at least one space or separator character from the format string.
+SELECT to_timestamp('2000    JUN', 'FXYYYY MON');
+ERROR:  unexpected character " "
+HINT:  In FX mode, punctuation in the input string must exactly match the format string.
 SELECT to_date('2011 12  18', 'YYYY MM DD');
   to_date   
 ------------
@@ -2984,13 +3041,13 @@ SELECT to_date('2011 12  18', 'YYYY MM  DD');
 SELECT to_date('2011 12  18', 'YYYY MM   DD');
   to_date   
 ------------
- 12-08-2011
+ 12-18-2011
 (1 row)
 
 SELECT to_date('2011 12 18', 'YYYY  MM DD');
   to_date   
 ------------
- 02-18-2011
+ 12-18-2011
 (1 row)
 
 SELECT to_date('2011  12 18', 'YYYY  MM DD');
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index a7bc9dcfc4..1dbaf8ee46 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,21 @@ SELECT to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD --> HH:MI:SS');
 
 SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS');
 
+SELECT to_timestamp('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS');
+
 SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD');
 
+SELECT to_timestamp('1985 FMMonth 12', 'YYYY "FMMonth" DD');
+
+SELECT to_timestamp('1985 \ 12', 'YYYY \\ DD');
+
 SELECT to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16',
-                    '"My birthday-> Year" YYYY, "Month:" FMMonth, "Day:" DD');
+                    '"My birthday-> Year:" YYYY, "Month:" FMMonth, "Day:" DD');
 
 SELECT to_timestamp('1,582nd VIII 21', 'Y,YYYth FMRM DD');
 
 SELECT to_timestamp('15 "text between quote marks" 98 54 45',
-                    E'HH24 "\\text between quote marks\\"" YY MI SS');
+                    E'HH24 "\\"text between quote marks\\"" YY MI SS');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +414,12 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 
 SELECT to_timestamp('97/Feb/16', 'YYMonDD');
 
+SELECT to_timestamp('97/Feb/16', 'YY:Mon:DD');
+
+SELECT to_timestamp('97/Feb/16', 'FXYY:Mon:DD');
+
+SELECT to_timestamp('97/Feb/16', 'FXYY/Mon/DD');
+
 SELECT to_timestamp('19971116', 'YYYYMMDD');
 
 SELECT to_timestamp('20000-1116', 'YYYY-MMDD');
@@ -458,6 +470,13 @@ SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD HH24:MI:SS');
 SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD  HH24:MI:SS');
 SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD   HH24:MI:SS');
 
+SELECT to_timestamp('2000----JUN', 'YYYY MON');
+SELECT to_timestamp('2000 +   JUN', 'YYYY MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000--JUN', 'YYYY/MON');
+SELECT to_timestamp('2000    JUN', 'FXYYYY MON');
+
 SELECT to_date('2011 12  18', 'YYYY MM DD');
 SELECT to_date('2011 12  18', 'YYYY MM  DD');
 SELECT to_date('2011 12  18', 'YYYY MM   DD');
