Bug in to_timestamp().

From e79001a912c9b8bfbcd5eef24fca61f4ac08becb Mon Sep 17 00:00:00 2001
From: Amul Sul <sul_amul@yahoo.co.in>
Date: Wed, 15 Jun 2016 14:42:43 +0530
Subject: [PATCH] RM37358: space in the format string should skip a whitespace
 in input

---
 src/backend/utils/adt/formatting.c     | 20 ++++++++++++++++----
 src/test/regress/expected/horology.out | 12 ++++++------
 src/test/regress/sql/horology.sql      |  4 ++--
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index ae93fe0..ccacc09 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -2955,11 +2955,23 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		if (n->type != NODE_TYPE_ACTION)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * Ignore spaces when not in FX (fixed width) mode and space in
+			 * the format string.
 			 */
-			s++;
+			if (!fx_mode && isspace((unsigned char) n->character))
+			{
+				while (*s != '\0' && isspace((unsigned char) *s))
+					s++;
+			}
+			else
+			{
+				/*
+				 * Separator, so consume one character from input string.
+				 * Notice we don't insist that the consumed character match
+				 * the format's character.
+				 */
+				s++;
+			}
 			continue;
 		}
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 1fe02be..98a9681 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2776,7 +2776,7 @@ SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD');
 (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 +2789,7 @@ 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
@@ -2912,7 +2912,7 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
 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');
@@ -2942,7 +2942,7 @@ 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_date('2011 12  18', 'YYYY MM DD');
@@ -2960,13 +2960,13 @@ 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 c81437b..71f0acf 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -395,12 +395,12 @@ SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS');
 SELECT to_timestamp('1985 January 12', 'YYYY FMMonth 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');
 
-- 
2.6.2

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7830334..5656245 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6083,9 +6083,10 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces in the input string and in the formatting
+       string unless the <literal>FX</literal> option is used. For example,
+       <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
@@ -6121,6 +6122,19 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        skips two input characters.
       </para>
      </listitem>
+     
+     <listitem>
+      <para>
+       In <function>to_date</> and <function>to_timestamp</> separator
+       characters <literal>','</literal>, <literal>'-'</literal>,
+       <literal>'.'</literal>, <literal>'/'</literal> and <literal>':'</literal>
+       outside of double-quoted strings skip the number of input characters
+       contained in the string unless the <literal>FX</literal> option is used.
+       If <literal>FX</literal> option is specified then consumed separator
+       character in the formatting string must match the separator character
+       in the input string.
+      </para>
+     </listitem>
 
      <listitem>
       <para>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index bbd97dc..ef39df9 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -947,6 +949,7 @@ typedef struct NUMProc
 static const KeyWord *index_seq_search(char *str, const KeyWord *kw,
 				 const int *index);
 static const KeySuffix *suff_search(char *str, const KeySuffix *suf, int type);
+static bool is_char_separator(char *str);
 static void NUMDesc_prepare(NUMDesc *num, FormatNode *n);
 static void parse_format(FormatNode *node, char *str, const KeyWord *kw,
 			 const KeySuffix *suf, const int *index, int ver, NUMDesc *Num);
@@ -963,7 +966,6 @@ 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);
@@ -1036,6 +1038,16 @@ suff_search(char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(char *str)
+{
+	return (*str == ',' ||
+			*str == '-' ||
+			*str == '.' ||
+			*str == '/' ||
+			*str == ':');
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1237,9 +1249,10 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1251,6 +1264,49 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				n->type = NODE_TYPE_CHAR;
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1290,48 +1346,30 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1348,6 +1386,17 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 	return;
@@ -2081,20 +2130,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2164,11 +2199,6 @@ 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);
 
@@ -2948,20 +2978,71 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	char	   *s;
 	int			len,
 				value;
-	bool		fx_mode = false;
+	bool		in_space = false,
+				fx_mode = false;
 
 	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)
+		{
+			/*
+			 * Previous node was a space node. In non FX (fixed format) mode we
+			 * skiped all spaces in the previous step.
+			 */
+			if (in_space && !fx_mode)
+				continue;
+
+			if (!isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("expected space character in given string"),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for space field.")));
+			s++;
+			/* If not in FX (fixed format) mode skip other spaces */
+			if (!fx_mode)
+				while (*s != '\0' && isspace(*s))
+					s++;
+
+			in_space = true;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_SEPARATOR)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In FX mode we don't insist that consumed separator match the
+			 * format's separator character.
 			 */
+			if (!fx_mode && !is_char_separator(s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("expected separator character in input string"),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for separator field.")));
+			else if (fx_mode && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected separator \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for separator field.")));
 			s++;
+			in_space = false;
 			continue;
 		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
+			in_space = false;
+			continue;
+		}
+		in_space = false;
 
 		/* Ignore spaces before fields when not in FX (fixed width) mode */
 		if (!fx_mode && n->key->id != DCH_FX)
@@ -3340,15 +3421,17 @@ datetime_to_char_body(TmToChar *tmtc, text *fmt, bool is_interval, Oid collid)
 
 		if ((ent = DCH_cache_search(fmt_str)) == NULL)
 		{
-			ent = DCH_cache_getnew(fmt_str);
+			FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, fmt_str, DCH_keywords,
+			parse_format(buf, fmt_str, DCH_keywords,
 						 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+			ent = DCH_cache_getnew(fmt_str);
+			memcpy(ent->format, buf, sizeof(buf));
 			(ent->format + fmt_len)->type = NODE_TYPE_END;		/* Paranoia? */
 
 #ifdef DEBUG_TO_FROM_CHAR
@@ -3604,15 +3687,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if ((ent = DCH_cache_search(fmt_str)) == NULL)
 			{
-				ent = DCH_cache_getnew(fmt_str);
+				FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 				/*
 				 * Not in the cache, must run parser and save a new
 				 * format-picture to the cache.
 				 */
-				parse_format(ent->format, fmt_str, DCH_keywords,
+				parse_format(buf, fmt_str, DCH_keywords,
 							 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+				ent = DCH_cache_getnew(fmt_str);
+				memcpy(ent->format, buf, sizeof(buf));
 				(ent->format + fmt_len)->type = NODE_TYPE_END;	/* Paranoia? */
 #ifdef DEBUG_TO_FROM_CHAR
 				/* dump_node(ent->format, fmt_len); */
@@ -3981,32 +4066,41 @@ NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree)
 
 		if ((ent = NUM_cache_search(str)) == NULL)
 		{
-			ent = NUM_cache_getnew(str);
+			FormatNode	buf[NUM_CACHE_SIZE + 1];
+
+			zeroize_NUM(Num);
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, str, NUM_keywords,
-						 NULL, NUM_index, NUM_TYPE, &ent->Num);
+			parse_format(buf, str, NUM_keywords,
+						 NULL, NUM_index, NUM_TYPE, Num);
+
+			ent = NUM_cache_getnew(str);
+
+			memcpy(ent->format, buf, sizeof(buf));
+			memcpy(&ent->Num, Num, sizeof(NUMDesc));
 
 			(ent->format + len)->type = NODE_TYPE_END;	/* Paranoia? */
 		}
+		else
+		{
+			/*
+			 * Copy cache to used struct
+			 */
+			Num->flag = ent->Num.flag;
+			Num->lsign = ent->Num.lsign;
+			Num->pre = ent->Num.pre;
+			Num->post = ent->Num.post;
+			Num->pre_lsign_num = ent->Num.pre_lsign_num;
+			Num->need_locale = ent->Num.need_locale;
+			Num->multi = ent->Num.multi;
+			Num->zero_start = ent->Num.zero_start;
+			Num->zero_end = ent->Num.zero_end;
+		}
 
 		format = ent->format;
-
-		/*
-		 * Copy cache to used struct
-		 */
-		Num->flag = ent->Num.flag;
-		Num->lsign = ent->Num.lsign;
-		Num->pre = ent->Num.pre;
-		Num->post = ent->Num.post;
-		Num->pre_lsign_num = ent->Num.pre_lsign_num;
-		Num->need_locale = ent->Num.need_locale;
-		Num->multi = ent->Num.multi;
-		Num->zero_start = ent->Num.zero_start;
-		Num->zero_end = ent->Num.zero_end;
 	}
 
 #ifdef DEBUG_TO_FROM_CHAR
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 1fe02be..d6290f2 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2763,6 +2763,9 @@ SELECT to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD --> HH:MI:SS');
  Sat Feb 16 08:14:30 0097 PST
 (1 row)
 
+SELECT to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD ---> HH:MI:SS');
+ERROR:  expected separator character in input string
+DETAIL:  The given value did not match any of the allowed values for separator field.
 SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS');
          to_timestamp         
 ------------------------------
@@ -2775,8 +2778,20 @@ SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD');
  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 +2804,7 @@ 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
@@ -2810,6 +2825,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator "/", expected ":"
+DETAIL:  The given value did not match any of the allowed values for separator field.
+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         
 ------------------------------
@@ -2912,7 +2942,7 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
 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');
@@ -2942,7 +2972,7 @@ 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_date('2011 12  18', 'YYYY MM DD');
@@ -2960,13 +2990,13 @@ 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 c81437b..c3da350 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -390,17 +390,23 @@ RESET DateStyle;
 
 SELECT to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD --> HH:MI:SS');
 
+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('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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7830334..559c55f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6083,9 +6083,12 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
-       skip multiple blank spaces in the input string unless the
+       skip multiple blank spaces and printable non letter and non digit
+       characters in the input string and in the formatting 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>,
+       <literal>to_timestamp('2000----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
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index bbd97dc..b14678d 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -947,6 +949,7 @@ typedef struct NUMProc
 static const KeyWord *index_seq_search(char *str, const KeyWord *kw,
 				 const int *index);
 static const KeySuffix *suff_search(char *str, const KeySuffix *suf, int type);
+static bool is_char_separator(char *str);
 static void NUMDesc_prepare(NUMDesc *num, FormatNode *n);
 static void parse_format(FormatNode *node, char *str, const KeyWord *kw,
 			 const KeySuffix *suf, const int *index, int ver, NUMDesc *Num);
@@ -963,7 +966,6 @@ 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);
@@ -1036,6 +1038,17 @@ suff_search(char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(char *str)
+{
+	return ((pg_mblen(str) == 1) &&
+			/* printable character, but not letter and digit */
+			((*str >= '!' && *str <= '/') ||
+			 (*str >= ':' && *str <= '@') ||
+			 (*str >= '[' && *str <= '`') ||
+			 (*str >= '{' && *str <= '~')));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1237,9 +1250,10 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1251,6 +1265,49 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				n->type = NODE_TYPE_CHAR;
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1290,48 +1347,30 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1348,6 +1387,17 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 	return;
@@ -2081,20 +2131,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2164,11 +2200,6 @@ 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);
 
@@ -2952,23 +2983,62 @@ 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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
+			 */
+			if (!fx_mode)
+			{
+				if (isspace(*s) || is_char_separator(s))
+					s++;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
+			s++;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
 			continue;
 		}
 
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
+		/* Ignore spaces before fields when not in FX (fixed * width) mode */
 		if (!fx_mode && n->key->id != DCH_FX)
 		{
-			while (*s != '\0' && isspace((unsigned char) *s))
+			while (*s != '\0' && (isspace((unsigned char) *s)))
 				s++;
 		}
+		else if (isspace(*s) || is_char_separator(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3340,15 +3410,17 @@ datetime_to_char_body(TmToChar *tmtc, text *fmt, bool is_interval, Oid collid)
 
 		if ((ent = DCH_cache_search(fmt_str)) == NULL)
 		{
-			ent = DCH_cache_getnew(fmt_str);
+			FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, fmt_str, DCH_keywords,
+			parse_format(buf, fmt_str, DCH_keywords,
 						 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+			ent = DCH_cache_getnew(fmt_str);
+			memcpy(ent->format, buf, sizeof(buf));
 			(ent->format + fmt_len)->type = NODE_TYPE_END;		/* Paranoia? */
 
 #ifdef DEBUG_TO_FROM_CHAR
@@ -3604,15 +3676,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if ((ent = DCH_cache_search(fmt_str)) == NULL)
 			{
-				ent = DCH_cache_getnew(fmt_str);
+				FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 				/*
 				 * Not in the cache, must run parser and save a new
 				 * format-picture to the cache.
 				 */
-				parse_format(ent->format, fmt_str, DCH_keywords,
+				parse_format(buf, fmt_str, DCH_keywords,
 							 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+				ent = DCH_cache_getnew(fmt_str);
+				memcpy(ent->format, buf, sizeof(buf));
 				(ent->format + fmt_len)->type = NODE_TYPE_END;	/* Paranoia? */
 #ifdef DEBUG_TO_FROM_CHAR
 				/* dump_node(ent->format, fmt_len); */
@@ -3981,32 +4055,41 @@ NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree)
 
 		if ((ent = NUM_cache_search(str)) == NULL)
 		{
-			ent = NUM_cache_getnew(str);
+			FormatNode	buf[NUM_CACHE_SIZE + 1];
+
+			zeroize_NUM(Num);
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, str, NUM_keywords,
-						 NULL, NUM_index, NUM_TYPE, &ent->Num);
+			parse_format(buf, str, NUM_keywords,
+						 NULL, NUM_index, NUM_TYPE, Num);
+
+			ent = NUM_cache_getnew(str);
+
+			memcpy(ent->format, buf, sizeof(buf));
+			memcpy(&ent->Num, Num, sizeof(NUMDesc));
 
 			(ent->format + len)->type = NODE_TYPE_END;	/* Paranoia? */
 		}
+		else
+		{
+			/*
+			 * Copy cache to used struct
+			 */
+			Num->flag = ent->Num.flag;
+			Num->lsign = ent->Num.lsign;
+			Num->pre = ent->Num.pre;
+			Num->post = ent->Num.post;
+			Num->pre_lsign_num = ent->Num.pre_lsign_num;
+			Num->need_locale = ent->Num.need_locale;
+			Num->multi = ent->Num.multi;
+			Num->zero_start = ent->Num.zero_start;
+			Num->zero_end = ent->Num.zero_end;
+		}
 
 		format = ent->format;
-
-		/*
-		 * Copy cache to used struct
-		 */
-		Num->flag = ent->Num.flag;
-		Num->lsign = ent->Num.lsign;
-		Num->pre = ent->Num.pre;
-		Num->post = ent->Num.post;
-		Num->pre_lsign_num = ent->Num.pre_lsign_num;
-		Num->need_locale = ent->Num.need_locale;
-		Num->multi = ent->Num.multi;
-		Num->zero_start = ent->Num.zero_start;
-		Num->zero_end = ent->Num.zero_end;
 	}
 
 #ifdef DEBUG_TO_FROM_CHAR
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 1fe02be..0bf4287 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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         
 ------------------------------
@@ -2912,7 +2945,7 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
 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');
@@ -2942,7 +2975,7 @@ 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_date('2011 12  18', 'YYYY MM DD');
@@ -2960,13 +2993,13 @@ 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 c81437b..514c124 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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 559c55f..e86dd0c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6100,13 +6100,9 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
        exist to handle input formats that cannot be converted by
-       simple casting.  These functions interpret input liberally,
-       with minimal error checking.  While they produce valid output,
-       the conversion can yield unexpected results.  For example,
-       input to these functions is not restricted by normal ranges,
-       thus <literal>to_date('20096040','YYYYMMDD')</literal> returns
-       <literal>2014-01-17</literal> rather than causing an error.
-       Casting does not have this behavior.
+       simple casting.  These functions have error checking as well as casting.
+       For example, <literal>to_date('20096040','YYYYMMDD')</literal> returns
+       an error.
       </para>
      </listitem>
 
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index b14678d..98d9847 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3635,7 +3635,10 @@ do_to_timestamp(text *date_txt, text *fmt,
 {
 	FormatNode *format;
 	TmFromChar	tmfc;
-	int			fmt_len;
+	int			fmt_len,
+				fmask = 0,		/* Bit mask for ValidateDate() */
+				dterr;
+	char	   *date_str = NULL;
 
 	ZERO_tmfc(&tmfc);
 	ZERO_tm(tm);
@@ -3646,7 +3649,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (fmt_len)
 	{
 		char	   *fmt_str;
-		char	   *date_str;
 		bool		incache;
 
 		fmt_str = text_to_cstring(fmt);
@@ -3704,7 +3706,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 		DCH_from_char(format, date_str, &tmfc);
 
-		pfree(date_str);
 		pfree(fmt_str);
 		if (!incache)
 			pfree(format);
@@ -3780,6 +3781,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			if (tmfc.bc && tm->tm_year > 0)
 				tm->tm_year = -(tm->tm_year - 1);
 		}
+		fmask |= DTK_M(YEAR);
 	}
 	else if (tmfc.cc)			/* use first year of century */
 	{
@@ -3791,10 +3793,14 @@ do_to_timestamp(text *date_txt, text *fmt,
 		else
 			/* +1 because year == 599 is 600 BC */
 			tm->tm_year = tmfc.cc * 100 + 1;
+		fmask |= DTK_M(YEAR);
 	}
 
 	if (tmfc.j)
+	{
 		j2date(tmfc.j, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+		fmask |= DTK_DATE_M;
+	}
 
 	if (tmfc.ww)
 	{
@@ -3808,6 +3814,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 				isoweekdate2date(tmfc.ww, tmfc.d, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 			else
 				isoweek2date(tmfc.ww, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 			tmfc.ddd = (tmfc.ww - 1) * 7 + 1;
@@ -3818,11 +3825,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (tmfc.d)
 		tm->tm_wday = tmfc.d - 1;		/* convert to native numbering */
 	if (tmfc.dd)
+	{
 		tm->tm_mday = tmfc.dd;
+		fmask |= DTK_M(DAY);
+	}
 	if (tmfc.ddd)
 		tm->tm_yday = tmfc.ddd;
 	if (tmfc.mm)
+	{
 		tm->tm_mon = tmfc.mm;
+		fmask |= DTK_M(MONTH);
+	}
 
 	if (tmfc.ddd && (tm->tm_mon <= 1 || tm->tm_mday <= 1))
 	{
@@ -3845,6 +3858,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			j0 = isoweek2j(tm->tm_year, 1) - 1;
 
 			j2date(j0 + tmfc.ddd, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 		{
@@ -3867,9 +3881,36 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if (tm->tm_mday <= 1)
 				tm->tm_mday = tmfc.ddd - y[i - 1];
+
+			fmask |= DTK_M(MONTH) | DTK_M(DAY);
 		}
 	}
 
+	/* Validate date with bit mask received above */
+	if (fmask != 0 && date_str)
+	{
+		dterr = ValidateDate(fmask, false, false, false, tm);
+		if (dterr != 0)
+			DateTimeParseError(dterr, date_str, "");
+	}
+
+	/* Do checks for time part */
+#ifdef HAVE_INT64_TIMESTAMP
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < INT64CONST(0) ||
+		*fsec > USECS_PER_SEC)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#else
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < 0 || *fsec > 1)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#endif
+
+	if (date_str)
+		pfree(date_str);
+
 #ifdef HAVE_INT64_TIMESTAMP
 	if (tmfc.ms)
 		*fsec += tmfc.ms * 1000;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 0bf4287..8ee6569 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -3015,7 +3015,7 @@ SELECT to_date('2011   12 18', 'YYYY  MM DD');
 (1 row)
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 -- Mixture of date conventions (ISO week and Gregorian):
 SELECT to_timestamp('2005527', 'YYYYIWID');
@@ -3043,6 +3043,12 @@ DETAIL:  Value must be an integer.
 SELECT to_timestamp('10000000000', 'FMYYYY');
 ERROR:  value for "YYYY" in source string is out of range
 DETAIL:  Value must be in the range -2147483648 to 2147483647.
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+ERROR:  date/time field value out of range: "2016-06-13 99:99:99"
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+ERROR:  date/time field value out of range: "2016-02-30"
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index 514c124..327dbfd 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -473,7 +473,7 @@ SELECT to_date('2011  12 18', 'YYYY  MM DD');
 SELECT to_date('2011   12 18', 'YYYY  MM DD');
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 
 -- Mixture of date conventions (ISO week and Gregorian):
@@ -494,6 +494,12 @@ SELECT to_timestamp('199711xy', 'YYYYMMDD');
 -- Input that doesn't fit in an int:
 SELECT to_timestamp('10000000000', 'FMYYYY');
 
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6355300..0fe50e1 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6146,9 +6146,12 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
-       skip multiple blank spaces in the input string unless the
+       skip multiple blank spaces and printable non letter and non digit
+       characters in the input string and in the formatting 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>,
+       <literal>to_timestamp('2000----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
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index bbd97dc..a3dbcaf 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -947,6 +949,7 @@ typedef struct NUMProc
 static const KeyWord *index_seq_search(char *str, const KeyWord *kw,
 				 const int *index);
 static const KeySuffix *suff_search(char *str, const KeySuffix *suf, int type);
+static bool is_char_separator(char *str);
 static void NUMDesc_prepare(NUMDesc *num, FormatNode *n);
 static void parse_format(FormatNode *node, char *str, const KeyWord *kw,
 			 const KeySuffix *suf, const int *index, int ver, NUMDesc *Num);
@@ -963,7 +966,6 @@ 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);
@@ -1036,6 +1038,17 @@ suff_search(char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(char *str)
+{
+	return ((pg_mblen(str) == 1) &&
+			/* printable character, but not letter and digit */
+			((*str >= '!' && *str <= '/') ||
+			 (*str >= ':' && *str <= '@') ||
+			 (*str >= '[' && *str <= '`') ||
+			 (*str >= '{' && *str <= '~')));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1237,9 +1250,10 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1251,6 +1265,55 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1290,48 +1353,30 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1348,6 +1393,17 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 	return;
@@ -2081,20 +2137,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2164,11 +2206,6 @@ 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);
 
@@ -2947,19 +2984,56 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	FormatNode *n;
 	char	   *s;
 	int			len,
-				value;
+				value,
+				prev_type;
 	bool		fx_mode = false;
 
 	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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
 			 */
+			if (!fx_mode)
+			{
+				if (isspace(*s) || is_char_separator(s))
+					s++;
+				prev_type = n->type;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
 			s++;
+			prev_type = n->type;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
+			prev_type = n->type;
 			continue;
 		}
 
@@ -2968,7 +3042,20 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		{
 			while (*s != '\0' && isspace((unsigned char) *s))
 				s++;
+			/*
+			 * Ignore separator characters if previous node was space or 
+			 * separator and current is not.
+			 */
+			if (prev_type == NODE_TYPE_SPACE || prev_type == NODE_TYPE_SEPARATOR)
+				while (*s != '\0' && is_char_separator(s))
+					s++;
 		}
+		else if (isspace(*s) || is_char_separator(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3207,6 +3294,7 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+		prev_type = n->type;
 	}
 }
 
@@ -3340,15 +3428,17 @@ datetime_to_char_body(TmToChar *tmtc, text *fmt, bool is_interval, Oid collid)
 
 		if ((ent = DCH_cache_search(fmt_str)) == NULL)
 		{
-			ent = DCH_cache_getnew(fmt_str);
+			FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, fmt_str, DCH_keywords,
+			parse_format(buf, fmt_str, DCH_keywords,
 						 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+			ent = DCH_cache_getnew(fmt_str);
+			memcpy(ent->format, buf, sizeof(buf));
 			(ent->format + fmt_len)->type = NODE_TYPE_END;		/* Paranoia? */
 
 #ifdef DEBUG_TO_FROM_CHAR
@@ -3604,15 +3694,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if ((ent = DCH_cache_search(fmt_str)) == NULL)
 			{
-				ent = DCH_cache_getnew(fmt_str);
+				FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 				/*
 				 * Not in the cache, must run parser and save a new
 				 * format-picture to the cache.
 				 */
-				parse_format(ent->format, fmt_str, DCH_keywords,
+				parse_format(buf, fmt_str, DCH_keywords,
 							 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+				ent = DCH_cache_getnew(fmt_str);
+				memcpy(ent->format, buf, sizeof(buf));
 				(ent->format + fmt_len)->type = NODE_TYPE_END;	/* Paranoia? */
 #ifdef DEBUG_TO_FROM_CHAR
 				/* dump_node(ent->format, fmt_len); */
@@ -3981,32 +4073,41 @@ NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree)
 
 		if ((ent = NUM_cache_search(str)) == NULL)
 		{
-			ent = NUM_cache_getnew(str);
+			FormatNode	buf[NUM_CACHE_SIZE + 1];
+
+			zeroize_NUM(Num);
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, str, NUM_keywords,
-						 NULL, NUM_index, NUM_TYPE, &ent->Num);
+			parse_format(buf, str, NUM_keywords,
+						 NULL, NUM_index, NUM_TYPE, Num);
+
+			ent = NUM_cache_getnew(str);
+
+			memcpy(ent->format, buf, sizeof(buf));
+			memcpy(&ent->Num, Num, sizeof(NUMDesc));
 
 			(ent->format + len)->type = NODE_TYPE_END;	/* Paranoia? */
 		}
+		else
+		{
+			/*
+			 * Copy cache to used struct
+			 */
+			Num->flag = ent->Num.flag;
+			Num->lsign = ent->Num.lsign;
+			Num->pre = ent->Num.pre;
+			Num->post = ent->Num.post;
+			Num->pre_lsign_num = ent->Num.pre_lsign_num;
+			Num->need_locale = ent->Num.need_locale;
+			Num->multi = ent->Num.multi;
+			Num->zero_start = ent->Num.zero_start;
+			Num->zero_end = ent->Num.zero_end;
+		}
 
 		format = ent->format;
-
-		/*
-		 * Copy cache to used struct
-		 */
-		Num->flag = ent->Num.flag;
-		Num->lsign = ent->Num.lsign;
-		Num->pre = ent->Num.pre;
-		Num->post = ent->Num.post;
-		Num->pre_lsign_num = ent->Num.pre_lsign_num;
-		Num->need_locale = ent->Num.need_locale;
-		Num->multi = ent->Num.multi;
-		Num->zero_start = ent->Num.zero_start;
-		Num->zero_end = ent->Num.zero_end;
 	}
 
 #ifdef DEBUG_TO_FROM_CHAR
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 1fe02be..46d4c7b 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
@@ -2789,12 +2807,18 @@ 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
 (1 row)
 
+SELECT to_timestamp('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
+         to_timestamp         
+------------------------------
+ Sun May 16 00:00:00 1976 PDT
+(1 row)
+
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
          to_timestamp         
 ------------------------------
@@ -2810,6 +2834,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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         
 ------------------------------
@@ -2912,7 +2951,7 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
 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');
@@ -2942,7 +2981,13 @@ 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');
          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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -2960,13 +3005,13 @@ 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 c81437b..966cde1 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,23 @@ 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('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +416,12 @@ 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');
@@ -452,6 +466,8 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 559c55f..e86dd0c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6100,13 +6100,9 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
        exist to handle input formats that cannot be converted by
-       simple casting.  These functions interpret input liberally,
-       with minimal error checking.  While they produce valid output,
-       the conversion can yield unexpected results.  For example,
-       input to these functions is not restricted by normal ranges,
-       thus <literal>to_date('20096040','YYYYMMDD')</literal> returns
-       <literal>2014-01-17</literal> rather than causing an error.
-       Casting does not have this behavior.
+       simple casting.  These functions have error checking as well as casting.
+       For example, <literal>to_date('20096040','YYYYMMDD')</literal> returns
+       an error.
       </para>
      </listitem>
 
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index b14678d..98d9847 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3635,7 +3635,10 @@ do_to_timestamp(text *date_txt, text *fmt,
 {
 	FormatNode *format;
 	TmFromChar	tmfc;
-	int			fmt_len;
+	int			fmt_len,
+				fmask = 0,		/* Bit mask for ValidateDate() */
+				dterr;
+	char	   *date_str = NULL;
 
 	ZERO_tmfc(&tmfc);
 	ZERO_tm(tm);
@@ -3646,7 +3649,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (fmt_len)
 	{
 		char	   *fmt_str;
-		char	   *date_str;
 		bool		incache;
 
 		fmt_str = text_to_cstring(fmt);
@@ -3704,7 +3706,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 		DCH_from_char(format, date_str, &tmfc);
 
-		pfree(date_str);
 		pfree(fmt_str);
 		if (!incache)
 			pfree(format);
@@ -3780,6 +3781,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			if (tmfc.bc && tm->tm_year > 0)
 				tm->tm_year = -(tm->tm_year - 1);
 		}
+		fmask |= DTK_M(YEAR);
 	}
 	else if (tmfc.cc)			/* use first year of century */
 	{
@@ -3791,10 +3793,14 @@ do_to_timestamp(text *date_txt, text *fmt,
 		else
 			/* +1 because year == 599 is 600 BC */
 			tm->tm_year = tmfc.cc * 100 + 1;
+		fmask |= DTK_M(YEAR);
 	}
 
 	if (tmfc.j)
+	{
 		j2date(tmfc.j, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+		fmask |= DTK_DATE_M;
+	}
 
 	if (tmfc.ww)
 	{
@@ -3808,6 +3814,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 				isoweekdate2date(tmfc.ww, tmfc.d, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 			else
 				isoweek2date(tmfc.ww, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 			tmfc.ddd = (tmfc.ww - 1) * 7 + 1;
@@ -3818,11 +3825,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (tmfc.d)
 		tm->tm_wday = tmfc.d - 1;		/* convert to native numbering */
 	if (tmfc.dd)
+	{
 		tm->tm_mday = tmfc.dd;
+		fmask |= DTK_M(DAY);
+	}
 	if (tmfc.ddd)
 		tm->tm_yday = tmfc.ddd;
 	if (tmfc.mm)
+	{
 		tm->tm_mon = tmfc.mm;
+		fmask |= DTK_M(MONTH);
+	}
 
 	if (tmfc.ddd && (tm->tm_mon <= 1 || tm->tm_mday <= 1))
 	{
@@ -3845,6 +3858,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			j0 = isoweek2j(tm->tm_year, 1) - 1;
 
 			j2date(j0 + tmfc.ddd, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 		{
@@ -3867,9 +3881,36 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if (tm->tm_mday <= 1)
 				tm->tm_mday = tmfc.ddd - y[i - 1];
+
+			fmask |= DTK_M(MONTH) | DTK_M(DAY);
 		}
 	}
 
+	/* Validate date with bit mask received above */
+	if (fmask != 0 && date_str)
+	{
+		dterr = ValidateDate(fmask, false, false, false, tm);
+		if (dterr != 0)
+			DateTimeParseError(dterr, date_str, "");
+	}
+
+	/* Do checks for time part */
+#ifdef HAVE_INT64_TIMESTAMP
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < INT64CONST(0) ||
+		*fsec > USECS_PER_SEC)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#else
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < 0 || *fsec > 1)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#endif
+
+	if (date_str)
+		pfree(date_str);
+
 #ifdef HAVE_INT64_TIMESTAMP
 	if (tmfc.ms)
 		*fsec += tmfc.ms * 1000;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 0bf4287..8ee6569 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -3015,7 +3015,7 @@ SELECT to_date('2011   12 18', 'YYYY  MM DD');
 (1 row)
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 -- Mixture of date conventions (ISO week and Gregorian):
 SELECT to_timestamp('2005527', 'YYYYIWID');
@@ -3043,6 +3043,12 @@ DETAIL:  Value must be an integer.
 SELECT to_timestamp('10000000000', 'FMYYYY');
 ERROR:  value for "YYYY" in source string is out of range
 DETAIL:  Value must be in the range -2147483648 to 2147483647.
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+ERROR:  date/time field value out of range: "2016-06-13 99:99:99"
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+ERROR:  date/time field value out of range: "2016-02-30"
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index 514c124..327dbfd 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -473,7 +473,7 @@ SELECT to_date('2011  12 18', 'YYYY  MM DD');
 SELECT to_date('2011   12 18', 'YYYY  MM DD');
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 
 -- Mixture of date conventions (ISO week and Gregorian):
@@ -494,6 +494,12 @@ SELECT to_timestamp('199711xy', 'YYYYMMDD');
 -- Input that doesn't fit in an int:
 SELECT to_timestamp('10000000000', 'FMYYYY');
 
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5c1c4f6..36d8b3e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6146,9 +6146,12 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
-       skip multiple blank spaces in the input string unless the
+       skip multiple blank spaces and printable non letter and non digit
+       characters in the input string and in the formatting 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>,
+       <literal>to_timestamp('2000----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
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index bbd97dc..7430013 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -947,6 +949,7 @@ typedef struct NUMProc
 static const KeyWord *index_seq_search(char *str, const KeyWord *kw,
 				 const int *index);
 static const KeySuffix *suff_search(char *str, const KeySuffix *suf, int type);
+static bool is_char_separator(char *str);
 static void NUMDesc_prepare(NUMDesc *num, FormatNode *n);
 static void parse_format(FormatNode *node, char *str, const KeyWord *kw,
 			 const KeySuffix *suf, const int *index, int ver, NUMDesc *Num);
@@ -963,7 +966,6 @@ 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);
@@ -1036,6 +1038,17 @@ suff_search(char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(char *str)
+{
+	return ((pg_mblen(str) == 1) &&
+			/* printable character, but not letter and digit */
+			((*str >= '!' && *str <= '/') ||
+			 (*str >= ':' && *str <= '@') ||
+			 (*str >= '[' && *str <= '`') ||
+			 (*str >= '{' && *str <= '~')));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1237,9 +1250,10 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1251,6 +1265,55 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1290,48 +1353,30 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1348,6 +1393,17 @@ parse_format(FormatNode *node, char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 	return;
@@ -2081,20 +2137,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2164,11 +2206,6 @@ 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);
 
@@ -2947,19 +2984,56 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	FormatNode *n;
 	char	   *s;
 	int			len,
-				value;
+				value,
+				prev_type = NODE_TYPE_SPACE;
 	bool		fx_mode = false;
 
 	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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
 			 */
+			if (!fx_mode)
+			{
+				if (isspace(*s) || is_char_separator(s))
+					s++;
+				prev_type = n->type;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
 			s++;
+			prev_type = n->type;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
+			prev_type = n->type;
 			continue;
 		}
 
@@ -2968,7 +3042,20 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		{
 			while (*s != '\0' && isspace((unsigned char) *s))
 				s++;
+			/*
+			 * Ignore separator characters if previous node was space or
+			 * separator and current is not.
+			 */
+			if (prev_type == NODE_TYPE_SPACE || prev_type == NODE_TYPE_SEPARATOR)
+				while (*s != '\0' && is_char_separator(s))
+					s++;
 		}
+		else if (isspace(*s) || is_char_separator(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3207,6 +3294,7 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+		prev_type = n->type;
 	}
 }
 
@@ -3340,15 +3428,17 @@ datetime_to_char_body(TmToChar *tmtc, text *fmt, bool is_interval, Oid collid)
 
 		if ((ent = DCH_cache_search(fmt_str)) == NULL)
 		{
-			ent = DCH_cache_getnew(fmt_str);
+			FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, fmt_str, DCH_keywords,
+			parse_format(buf, fmt_str, DCH_keywords,
 						 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+			ent = DCH_cache_getnew(fmt_str);
+			memcpy(ent->format, buf, sizeof(buf));
 			(ent->format + fmt_len)->type = NODE_TYPE_END;		/* Paranoia? */
 
 #ifdef DEBUG_TO_FROM_CHAR
@@ -3604,15 +3694,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if ((ent = DCH_cache_search(fmt_str)) == NULL)
 			{
-				ent = DCH_cache_getnew(fmt_str);
+				FormatNode	buf[DCH_CACHE_SIZE + 1];
 
 				/*
 				 * Not in the cache, must run parser and save a new
 				 * format-picture to the cache.
 				 */
-				parse_format(ent->format, fmt_str, DCH_keywords,
+				parse_format(buf, fmt_str, DCH_keywords,
 							 DCH_suff, DCH_index, DCH_TYPE, NULL);
 
+				ent = DCH_cache_getnew(fmt_str);
+				memcpy(ent->format, buf, sizeof(buf));
 				(ent->format + fmt_len)->type = NODE_TYPE_END;	/* Paranoia? */
 #ifdef DEBUG_TO_FROM_CHAR
 				/* dump_node(ent->format, fmt_len); */
@@ -3981,32 +4073,41 @@ NUM_cache(int len, NUMDesc *Num, text *pars_str, bool *shouldFree)
 
 		if ((ent = NUM_cache_search(str)) == NULL)
 		{
-			ent = NUM_cache_getnew(str);
+			FormatNode	buf[NUM_CACHE_SIZE + 1];
+
+			zeroize_NUM(Num);
 
 			/*
 			 * Not in the cache, must run parser and save a new format-picture
 			 * to the cache.
 			 */
-			parse_format(ent->format, str, NUM_keywords,
-						 NULL, NUM_index, NUM_TYPE, &ent->Num);
+			parse_format(buf, str, NUM_keywords,
+						 NULL, NUM_index, NUM_TYPE, Num);
+
+			ent = NUM_cache_getnew(str);
+
+			memcpy(ent->format, buf, sizeof(buf));
+			memcpy(&ent->Num, Num, sizeof(NUMDesc));
 
 			(ent->format + len)->type = NODE_TYPE_END;	/* Paranoia? */
 		}
+		else
+		{
+			/*
+			 * Copy cache to used struct
+			 */
+			Num->flag = ent->Num.flag;
+			Num->lsign = ent->Num.lsign;
+			Num->pre = ent->Num.pre;
+			Num->post = ent->Num.post;
+			Num->pre_lsign_num = ent->Num.pre_lsign_num;
+			Num->need_locale = ent->Num.need_locale;
+			Num->multi = ent->Num.multi;
+			Num->zero_start = ent->Num.zero_start;
+			Num->zero_end = ent->Num.zero_end;
+		}
 
 		format = ent->format;
-
-		/*
-		 * Copy cache to used struct
-		 */
-		Num->flag = ent->Num.flag;
-		Num->lsign = ent->Num.lsign;
-		Num->pre = ent->Num.pre;
-		Num->post = ent->Num.post;
-		Num->pre_lsign_num = ent->Num.pre_lsign_num;
-		Num->need_locale = ent->Num.need_locale;
-		Num->multi = ent->Num.multi;
-		Num->zero_start = ent->Num.zero_start;
-		Num->zero_end = ent->Num.zero_end;
 	}
 
 #ifdef DEBUG_TO_FROM_CHAR
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 1fe02be..46d4c7b 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
@@ -2789,12 +2807,18 @@ 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
 (1 row)
 
+SELECT to_timestamp('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
+         to_timestamp         
+------------------------------
+ Sun May 16 00:00:00 1976 PDT
+(1 row)
+
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
          to_timestamp         
 ------------------------------
@@ -2810,6 +2834,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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         
 ------------------------------
@@ -2912,7 +2951,7 @@ SELECT to_timestamp('  20050302', 'YYYYMMDD');
 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');
@@ -2942,7 +2981,13 @@ 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');
          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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -2960,13 +3005,13 @@ 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 c81437b..966cde1 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,23 @@ 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('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +416,12 @@ 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');
@@ -452,6 +466,8 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 559c55f..e86dd0c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6100,13 +6100,9 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
        exist to handle input formats that cannot be converted by
-       simple casting.  These functions interpret input liberally,
-       with minimal error checking.  While they produce valid output,
-       the conversion can yield unexpected results.  For example,
-       input to these functions is not restricted by normal ranges,
-       thus <literal>to_date('20096040','YYYYMMDD')</literal> returns
-       <literal>2014-01-17</literal> rather than causing an error.
-       Casting does not have this behavior.
+       simple casting.  These functions have error checking as well as casting.
+       For example, <literal>to_date('20096040','YYYYMMDD')</literal> returns
+       an error.
       </para>
      </listitem>
 
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index b14678d..98d9847 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -3635,7 +3635,10 @@ do_to_timestamp(text *date_txt, text *fmt,
 {
 	FormatNode *format;
 	TmFromChar	tmfc;
-	int			fmt_len;
+	int			fmt_len,
+				fmask = 0,		/* Bit mask for ValidateDate() */
+				dterr;
+	char	   *date_str = NULL;
 
 	ZERO_tmfc(&tmfc);
 	ZERO_tm(tm);
@@ -3646,7 +3649,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (fmt_len)
 	{
 		char	   *fmt_str;
-		char	   *date_str;
 		bool		incache;
 
 		fmt_str = text_to_cstring(fmt);
@@ -3704,7 +3706,6 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 		DCH_from_char(format, date_str, &tmfc);
 
-		pfree(date_str);
 		pfree(fmt_str);
 		if (!incache)
 			pfree(format);
@@ -3780,6 +3781,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			if (tmfc.bc && tm->tm_year > 0)
 				tm->tm_year = -(tm->tm_year - 1);
 		}
+		fmask |= DTK_M(YEAR);
 	}
 	else if (tmfc.cc)			/* use first year of century */
 	{
@@ -3791,10 +3793,14 @@ do_to_timestamp(text *date_txt, text *fmt,
 		else
 			/* +1 because year == 599 is 600 BC */
 			tm->tm_year = tmfc.cc * 100 + 1;
+		fmask |= DTK_M(YEAR);
 	}
 
 	if (tmfc.j)
+	{
 		j2date(tmfc.j, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+		fmask |= DTK_DATE_M;
+	}
 
 	if (tmfc.ww)
 	{
@@ -3808,6 +3814,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 				isoweekdate2date(tmfc.ww, tmfc.d, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 			else
 				isoweek2date(tmfc.ww, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 			tmfc.ddd = (tmfc.ww - 1) * 7 + 1;
@@ -3818,11 +3825,17 @@ do_to_timestamp(text *date_txt, text *fmt,
 	if (tmfc.d)
 		tm->tm_wday = tmfc.d - 1;		/* convert to native numbering */
 	if (tmfc.dd)
+	{
 		tm->tm_mday = tmfc.dd;
+		fmask |= DTK_M(DAY);
+	}
 	if (tmfc.ddd)
 		tm->tm_yday = tmfc.ddd;
 	if (tmfc.mm)
+	{
 		tm->tm_mon = tmfc.mm;
+		fmask |= DTK_M(MONTH);
+	}
 
 	if (tmfc.ddd && (tm->tm_mon <= 1 || tm->tm_mday <= 1))
 	{
@@ -3845,6 +3858,7 @@ do_to_timestamp(text *date_txt, text *fmt,
 			j0 = isoweek2j(tm->tm_year, 1) - 1;
 
 			j2date(j0 + tmfc.ddd, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+			fmask |= DTK_DATE_M;
 		}
 		else
 		{
@@ -3867,9 +3881,36 @@ do_to_timestamp(text *date_txt, text *fmt,
 
 			if (tm->tm_mday <= 1)
 				tm->tm_mday = tmfc.ddd - y[i - 1];
+
+			fmask |= DTK_M(MONTH) | DTK_M(DAY);
 		}
 	}
 
+	/* Validate date with bit mask received above */
+	if (fmask != 0 && date_str)
+	{
+		dterr = ValidateDate(fmask, false, false, false, tm);
+		if (dterr != 0)
+			DateTimeParseError(dterr, date_str, "");
+	}
+
+	/* Do checks for time part */
+#ifdef HAVE_INT64_TIMESTAMP
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < INT64CONST(0) ||
+		*fsec > USECS_PER_SEC)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#else
+	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
+		tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE ||
+		*fsec < 0 || *fsec > 1)
+		DateTimeParseError(DTERR_FIELD_OVERFLOW, date_str, "");
+#endif
+
+	if (date_str)
+		pfree(date_str);
+
 #ifdef HAVE_INT64_TIMESTAMP
 	if (tmfc.ms)
 		*fsec += tmfc.ms * 1000;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 0bf4287..8ee6569 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -3015,7 +3015,7 @@ SELECT to_date('2011   12 18', 'YYYY  MM DD');
 (1 row)
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 -- Mixture of date conventions (ISO week and Gregorian):
 SELECT to_timestamp('2005527', 'YYYYIWID');
@@ -3043,6 +3043,12 @@ DETAIL:  Value must be an integer.
 SELECT to_timestamp('10000000000', 'FMYYYY');
 ERROR:  value for "YYYY" in source string is out of range
 DETAIL:  Value must be in the range -2147483648 to 2147483647.
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+ERROR:  date/time field value out of range: "2016-06-13 99:99:99"
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+ERROR:  date/time field value out of range: "2016-02-30"
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index 514c124..327dbfd 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -473,7 +473,7 @@ SELECT to_date('2011  12 18', 'YYYY  MM DD');
 SELECT to_date('2011   12 18', 'YYYY  MM DD');
 
 --
--- Check errors for some incorrect usages of to_timestamp()
+-- Check errors for some incorrect usages of to_timestamp() and to_date()
 --
 
 -- Mixture of date conventions (ISO week and Gregorian):
@@ -494,6 +494,12 @@ SELECT to_timestamp('199711xy', 'YYYYMMDD');
 -- Input that doesn't fit in an int:
 SELECT to_timestamp('10000000000', 'FMYYYY');
 
+-- Time overflow:
+SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
+
+-- Date overflow:
+SELECT to_date('2016-02-30', 'YYYY-MM-DD');
+
 --
 -- Check behavior with SQL-style fixed-GMT-offset time zone (cf bug #8572)
 --

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index a588350..96ed2c3 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6157,9 +6157,12 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
-       skip multiple blank spaces in the input string unless the
+       skip multiple blank spaces and printable non letter and non digit
+       characters in the input string and in the formatting 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>,
+       <literal>to_timestamp('2000----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
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index d4eaa50..7d50543 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -951,6 +953,7 @@ 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_char_separator(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);
@@ -967,7 +970,6 @@ 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);
@@ -1040,6 +1042,17 @@ suff_search(const char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(char *str)
+{
+	return ((pg_mblen(str) == 1) &&
+			/* printable character, but not letter and digit */
+			((*str >= '!' && *str <= '/') ||
+			 (*str >= ':' && *str <= '@') ||
+			 (*str >= '[' && *str <= '`') ||
+			 (*str >= '{' && *str <= '~')));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1225,9 +1238,10 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1239,6 +1253,55 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1278,48 +1341,30 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1336,6 +1381,17 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 }
@@ -2068,20 +2124,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2151,11 +2193,6 @@ 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);
 
@@ -2934,19 +2971,56 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	FormatNode *n;
 	char	   *s;
 	int			len,
-				value;
+				value,
+				prev_type = NODE_TYPE_SPACE;
 	bool		fx_mode = false;
 
 	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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
 			 */
+			if (!fx_mode)
+			{
+				if (isspace(*s) || is_char_separator(s))
+					s++;
+				prev_type = n->type;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
 			s++;
+			prev_type = n->type;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
+			prev_type = n->type;
 			continue;
 		}
 
@@ -2955,7 +3029,20 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		{
 			while (*s != '\0' && isspace((unsigned char) *s))
 				s++;
+			/*
+			 * Ignore separator characters if previous node was space or
+			 * separator and current is not.
+			 */
+			if (prev_type == NODE_TYPE_SPACE || prev_type == NODE_TYPE_SEPARATOR)
+				while (*s != '\0' && is_char_separator(s))
+					s++;
 		}
+		else if (isspace(*s) || is_char_separator(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3194,6 +3281,7 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+		prev_type = n->type;
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index f9d12e0..8c71c72 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
@@ -2789,12 +2807,18 @@ 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
 (1 row)
 
+SELECT to_timestamp('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
+         to_timestamp         
+------------------------------
+ Sun May 16 00:00:00 1976 PDT
+(1 row)
+
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
          to_timestamp         
 ------------------------------
@@ -2810,6 +2834,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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 +2975,7 @@ 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');
@@ -2966,7 +3005,13 @@ 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');
          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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -2984,13 +3029,13 @@ 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 a7bc9dc..6984f26 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,23 @@ 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('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +416,12 @@ 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 +472,8 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index a588350..96ed2c3 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6157,9 +6157,12 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <function>to_timestamp</function> and <function>to_date</function>
-       skip multiple blank spaces in the input string unless the
+       skip multiple blank spaces and printable non letter and non digit
+       characters in the input string and in the formatting 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>,
+       <literal>to_timestamp('2000----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
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index d4eaa50..7986228 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -951,6 +953,7 @@ 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_char_separator(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);
@@ -967,7 +970,6 @@ 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);
@@ -1040,6 +1042,17 @@ suff_search(const char *str, const KeySuffix *suf, int type)
 	return NULL;
 }
 
+static bool
+is_char_separator(const char *str)
+{
+	return ((pg_mblen(str) == 1) &&
+			/* printable character, but not letter and digit */
+			((*str >= '!' && *str <= '/') ||
+			 (*str >= ':' && *str <= '@') ||
+			 (*str >= '[' && *str <= '`') ||
+			 (*str >= '{' && *str <= '~')));
+}
+
 /* ----------
  * Prepare NUMDesc (number description struct) via FormatNode struct
  * ----------
@@ -1225,9 +1238,10 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1239,6 +1253,55 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			/* After backslash should go non-space character */
+			if (isspace(*str))
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("invalid escape sequence")));
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1278,48 +1341,30 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				n->type = NODE_TYPE_CHAR;
+				if (ver == DCH_TYPE && is_char_separator(str))
+					n->type = NODE_TYPE_SEPARATOR;
+				else if (isspace(*str))
+					n->type = NODE_TYPE_SPACE;
+				else
+					n->type = NODE_TYPE_CHAR;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1336,6 +1381,17 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 }
@@ -2068,20 +2124,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2151,11 +2193,6 @@ 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);
 
@@ -2934,19 +2971,56 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	FormatNode *n;
 	char	   *s;
 	int			len,
-				value;
+				value,
+				prev_type = NODE_TYPE_SPACE;
 	bool		fx_mode = false;
 
 	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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
 			 */
+			if (!fx_mode)
+			{
+				if (isspace(*s) || is_char_separator(s))
+					s++;
+				prev_type = n->type;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace(*s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
 			s++;
+			prev_type = n->type;
+			continue;
+		}
+		else if (n->type == NODE_TYPE_CHAR)
+		{
+			/*
+			 * 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++;
+			prev_type = n->type;
 			continue;
 		}
 
@@ -2955,7 +3029,20 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		{
 			while (*s != '\0' && isspace((unsigned char) *s))
 				s++;
+			/*
+			 * Ignore separator characters if previous node was space or
+			 * separator and current is not.
+			 */
+			if (prev_type == NODE_TYPE_SPACE || prev_type == NODE_TYPE_SEPARATOR)
+				while (*s != '\0' && is_char_separator(s))
+					s++;
 		}
+		else if (isspace(*s) || is_char_separator(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3194,6 +3281,7 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+		prev_type = n->type;
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index f9d12e0..8c71c72 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
@@ -2789,12 +2807,18 @@ 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
 (1 row)
 
+SELECT to_timestamp('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
+         to_timestamp         
+------------------------------
+ Sun May 16 00:00:00 1976 PDT
+(1 row)
+
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
          to_timestamp         
 ------------------------------
@@ -2810,6 +2834,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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 +2975,7 @@ 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');
@@ -2966,7 +3005,13 @@ 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');
          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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -2984,13 +3029,13 @@ 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 a7bc9dc..6984f26 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,23 @@ 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('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +416,12 @@ 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 +472,8 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..5a4e248 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6159,7 +6159,8 @@ 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
@@ -6169,6 +6170,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
 
      <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>
        templates and will be output literally.  You can put a substring
        in double quotes to force it to be interpreted as literal text
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index d4eaa50..d28ceec 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -169,6 +169,8 @@ struct FormatNode
 #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
@@ -951,6 +953,7 @@ 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);
@@ -967,7 +970,6 @@ 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);
@@ -1040,6 +1042,16 @@ 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
  * ----------
@@ -1225,9 +1237,10 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 {
 	const KeySuffix *s;
 	FormatNode *n;
+	bool		in_text = false,
+				in_backslash = false;
 	int			node_set = 0,
-				suffix,
-				last = 0;
+				suffix;
 
 #ifdef DEBUG_TO_FROM_CHAR
 	elog(DEBUG_elog_output, "to_char/number(): run parser");
@@ -1239,6 +1252,50 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 	{
 		suffix = 0;
 
+		/* Previous character was a backslash */
+		if (in_backslash)
+		{
+			in_backslash = false;
+
+			n->type = NODE_TYPE_CHAR;
+			n->character = *str;
+			n->key = NULL;
+			n->suffix = 0;
+			n++;
+			str++;
+			continue;
+		}
+		/* Previous character was a quote */
+		else if (in_text)
+		{
+			if (*str == '"')
+			{
+				str++;
+				in_text = false;
+			}
+			else if (*str == '\\')
+			{
+				str++;
+				in_backslash = true;
+			}
+			else
+			{
+				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;
+
+				n->character = *str;
+				n->key = NULL;
+				n->suffix = 0;
+				n++;
+				str++;
+			}
+			continue;
+		}
+
 		/*
 		 * Prefix
 		 */
@@ -1278,48 +1335,30 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 		else if (*str)
 		{
-			/*
-			 * Special characters '\' and '"'
-			 */
-			if (*str == '"' && last != '\\')
+			if (*str == '"')
 			{
-				int			x = 0;
-
-				while (*(++str))
-				{
-					if (*str == '"' && x != '\\')
-					{
-						str++;
-						break;
-					}
-					else if (*str == '\\' && x != '\\')
-					{
-						x = '\\';
-						continue;
-					}
-					n->type = NODE_TYPE_CHAR;
-					n->character = *str;
-					n->key = NULL;
-					n->suffix = 0;
-					++n;
-					x = *str;
-				}
+				in_text = true;
 				node_set = 0;
-				suffix = 0;
-				last = 0;
+				str++;
 			}
-			else if (*str && *str == '\\' && last != '\\' && *(str + 1) == '"')
+			else if (*str == '\\')
 			{
-				last = *str;
+				in_backslash = true;
+				node_set = 0;
 				str++;
 			}
-			else if (*str)
+			else
 			{
-				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;
+
 				n->character = *str;
 				n->key = NULL;
 				node_set = 1;
-				last = 0;
 				str++;
 			}
 		}
@@ -1336,6 +1375,17 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw,
 		}
 	}
 
+	if (in_backslash)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("invalid escape sequence")));
+
+	/* If we didn't meet closing quotes */
+	if (in_text)
+		ereport(ERROR,
+				(errcode(ERRCODE_SYNTAX_ERROR),
+				 errmsg("unexpected end of format string, expected '\"' character")));
+
 	n->type = NODE_TYPE_END;
 	n->suffix = 0;
 }
@@ -2068,20 +2118,6 @@ adjust_partial_year_to_2020(int year)
 		return 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.
  *
@@ -2151,11 +2187,6 @@ 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);
 
@@ -2934,19 +2965,62 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	FormatNode *n;
 	char	   *s;
 	int			len,
-				value;
+				value,
+				prev_type = NODE_TYPE_SPACE;
 	bool		fx_mode = false;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/* Ignore all spaces after previous field */
+		if (prev_type == NODE_TYPE_ACTION)
+			while (*s != '\0' && isspace((unsigned char) *s))
+				s++;
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
+		{
+			/*
+			 * In non FX (fixed format) mode we skip spaces and separator
+			 * characters.
+			 */
+			if (!fx_mode)
+			{
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+					s++;
+
+				prev_type = n->type;
+				continue;
+			}
+
+			/* Checks for FX mode */
+			if (n->type == NODE_TYPE_SPACE && !isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+			else if (n->type == NODE_TYPE_SEPARATOR && n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%c\", expected \"%c\"",
+								*s, n->character),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
+
+			s++;
+			prev_type = n->type;
+			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++;
+			prev_type = n->type;
 			continue;
 		}
 
@@ -2955,7 +3029,25 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 		{
 			while (*s != '\0' && isspace((unsigned char) *s))
 				s++;
+
+			/*
+			 * 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),
+						 errdetail("The given value did not match any of the allowed "
+								   "values for this field.")));
 		}
+		else if (isspace((unsigned char) *s) || is_separator_char(s))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+					 errmsg("unexpected character \"%c\"", *s),
+					 errdetail("The given value did not match any of the allowed "
+							   "values for this field.")));
 
 		from_char_set_mode(out, n->key->date_mode);
 
@@ -3194,6 +3286,7 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+		prev_type = n->type;
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index f9d12e0..96773fa 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
@@ -2789,12 +2807,18 @@ 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
 (1 row)
 
+SELECT to_timestamp('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
+         to_timestamp         
+------------------------------
+ Sun May 16 00:00:00 1976 PDT
+(1 row)
+
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
          to_timestamp         
 ------------------------------
@@ -2808,8 +2832,23 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 (1 row)
 
 SELECT to_timestamp('97/Feb/16', 'YYMonDD');
-ERROR:  invalid value "/Fe" for "Mon"
+ERROR:  unexpected character "/"
 DETAIL:  The given value did not match any of the allowed values for this field.
+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 ":"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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 +2975,7 @@ 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 +3005,30 @@ 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 "-"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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 "+"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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 "-"
+DETAIL:  The given value did not match any of the allowed values for this field.
 SELECT to_date('2011 12  18', 'YYYY MM DD');
   to_date   
 ------------
@@ -2984,13 +3044,13 @@ 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 a7bc9dc..2563980 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -392,15 +392,23 @@ 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('Year: 1976, Month: May, Day: 16', '"    Year:" YYYY, "Month:" FMMonth, "Day:"   DD');
 
 SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY');
 
@@ -408,6 +416,12 @@ 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 +472,12 @@ 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_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');

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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2428434030..545129334c 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6174,7 +6174,8 @@ 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
@@ -6182,6 +6183,19 @@ 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 b8bd4caa3e..dddfc4b1bf 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
@@ -961,6 +963,7 @@ 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);
@@ -1050,6 +1053,16 @@ 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
  * ----------
@@ -1325,7 +1338,14 @@ 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;
@@ -2996,12 +3016,53 @@ 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_ACTION)
 		{
 			/*
-			 * 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;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e6..3ebfa5111d 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,7 @@ 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_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3047,13 @@ 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 ebb196a1cf..e3305fc836 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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 487c7ff750..053d153d35 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6174,7 +6174,8 @@ 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
@@ -6182,6 +6183,19 @@ 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 b8bd4caa3e..35007bec5c 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
@@ -542,6 +544,10 @@ static const KeySuffix DCH_suff[] = {
 	{NULL, 0, 0, 0}
 };
 
+#define IS_SEPARATOR_CHAR(s) ( \
+	isprint(*(unsigned char*)(s)) && \
+	!isalpha(*(unsigned char*)(s)) && \
+	!isdigit(*(unsigned char*)(s)))
 
 /* ----------
  * Format-pictures (KeyWord).
@@ -1325,7 +1331,14 @@ 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;
@@ -2996,12 +3009,53 @@ 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 space character \"%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 separator character \"%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_ACTION)
 		{
 			/*
-			 * 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;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e6..6e50cfdbfa 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,7 @@ 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_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3047,13 @@ 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 ebb196a1cf..e3305fc836 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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 640ff09a7b..a34781378e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6174,7 +6174,8 @@ 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
@@ -6182,6 +6183,19 @@ 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 b8bd4caa3e..470cd4e187 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
@@ -542,7 +544,6 @@ static const KeySuffix DCH_suff[] = {
 	{NULL, 0, 0, 0}
 };
 
-
 /* ----------
  * Format-pictures (KeyWord).
  *
@@ -961,6 +962,7 @@ 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);
@@ -1050,6 +1052,16 @@ 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
  * ----------
@@ -1325,7 +1337,14 @@ 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;
@@ -2996,17 +3015,80 @@ 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)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * 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.
+			 */
+			else if (!isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected space character \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
+		}
+		else if (n->type == NODE_TYPE_SEPARATOR)
+		{
+			if (!fx_mode)
+			{
+				/*
+				 * Ignore spaces before separator character when not in FX
+				 * mode.
+				 */
+				while (*s != '\0' && isspace((unsigned char) *s))
+					s++;
+
+				/*
+				 * In non FX mode we don't insist that the consumed character
+				 * matches the format's character.
+				 */
+				if (is_separator_char(s))
+					s++;
+
+				continue;
+			}
+			/*
+			 * In FX mode we insist that separator character from the format
+			 * string matches separator character from the input string.
+			 */
+			else if (*n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected separator character \"%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_ACTION)
+		{
+			/*
+			 * 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)
 		{
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e6..fb595c7b17 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,31 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000  +JUN', 'YYYY//MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3071,13 @@ 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 ebb196a1cf..e9accdf30c 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');
@@ -464,6 +476,11 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1e535cf215..1cc8b078f7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6174,7 +6174,8 @@ 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
@@ -6182,6 +6183,19 @@ 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 b8bd4caa3e..a23122d3de 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
@@ -961,6 +963,7 @@ 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);
@@ -1050,6 +1053,16 @@ 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
  * ----------
@@ -1325,7 +1338,14 @@ 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;
@@ -2996,12 +3016,73 @@ 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)
+		{
+			/*
+			 * 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.
+			 */
+			else if (!isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected space character \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
+		}
+		else if (n->type == NODE_TYPE_SEPARATOR)
+		{
+			if (!fx_mode)
+			{
+				/*
+				 * Ignore spaces before separator character when not in FX
+				 * mode.
+				 */
+				while (*s != '\0' && isspace((unsigned char) *s))
+					s++;
+
+				/*
+				 * In non FX mode we don't insist that the consumed character
+				 * matches the format's character.
+				 */
+				if (is_separator_char(s))
+					s++;
+
+				continue;
+			}
+			/*
+			 * In FX mode we insist that separator character from the format
+			 * string matches separator character from the input string.
+			 */
+			else if (*n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected separator character \"%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_ACTION)
 		{
 			/*
-			 * 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;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e6..fb595c7b17 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,31 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000  +JUN', 'YYYY//MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3071,13 @@ 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 ebb196a1cf..e9accdf30c 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');
@@ -464,6 +476,11 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edc9be92a6..db1da7bee7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6264,7 +6264,8 @@ 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
@@ -6272,6 +6273,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       <function>to_timestamp</function> and <function>to_date</function> don't
+       skip multiple 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>
@@ -6287,6 +6301,20 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 11 it was possible to
+          skip input ordinary text using non letter and non digit characters.
+          For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> worked
+          before.  But currently to skip ordinary text in the input string it
+          is necessary to use only letter characters.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> or
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal> will
+          skip <literal>y</literal>, <literal>m</literal> and
+          <literal>d</literal> now.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575..e7547091cd 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2990,12 +3010,73 @@ 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)
+		{
+			/*
+			 * 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.
+			 */
+			else if (!isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected space character \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
+		}
+		else if (n->type == NODE_TYPE_SEPARATOR)
+		{
+			if (!fx_mode)
+			{
+				/*
+				 * Ignore spaces before separator character when not in FX
+				 * mode.
+				 */
+				while (*s != '\0' && isspace((unsigned char) *s))
+					s++;
+
+				/*
+				 * In non FX mode we don't insist that the consumed character
+				 * matches the format's character.
+				 */
+				if (is_separator_char(s))
+					s++;
+
+				continue;
+			}
+			/*
+			 * In FX mode we insist that separator character from the format
+			 * string matches separator character from the input string.
+			 */
+			else if (*n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected separator character \"%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_ACTION)
 		{
 			/*
-			 * 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;
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e6..fb595c7b17 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,31 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000  +JUN', 'YYYY//MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3071,13 @@ 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 ebb196a1cf..e9accdf30c 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');
@@ -464,6 +476,11 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edc9be92a6e..9281421f470 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6263,8 +6263,9 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       <para>
        <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>FX</literal> option is used.  For example,
+       <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
@@ -6272,6 +6273,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       <function>to_timestamp</function> and <function>to_date</function> don't
+       skip multiple 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>
@@ -6287,6 +6301,20 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 11 it was possible to
+          skip input ordinary text using non letter and non digit characters.
+          For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> worked
+          before.  But currently to skip ordinary text in the input string it
+          is necessary to use only letter characters.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> or
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal> will
+          skip <literal>y</literal>, <literal>m</literal> and
+          <literal>d</literal> now.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575d..2a7c049fc59 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,25 +3007,97 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped charaters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces in the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+
+		if (n->type == NODE_TYPE_SPACE)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we don't insist that the consumed
+			 * character matches the format's character.
 			 */
-			s += pg_mblen(s);
-			continue;
+			if (!fx_mode)
+			{
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+
+				continue;
+			}
+			/*
+			 * In FX mode we insist that whitespace from the format string
+			 * matches whitespace from the input string.
+			 */
+			else if (!isspace((unsigned char) *s))
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected space character \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
 		}
+		else if (n->type == NODE_TYPE_SEPARATOR)
+		{
+			/*
+			 * In non FX mode we don't insist that the consumed character
+			 * matches the format's character.
+			 */
+			if (!fx_mode)
+			{
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+
+				continue;
+			}
+			/*
+			 * In FX mode we insist that separator character from the format
+			 * string matches separator character from the input string.
+			 */
+			else if (*n->character != *s)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+						 errmsg("unexpected character \"%.*s\", expected separator character \"%s\"",
+								pg_mblen(s), s, n->character),
+						 errhint("In FX mode, punctuation in the input string "
+								 "must exactly match the format string.")));
 
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
+			s++;
+			continue;
+		}
+		else if (n->type != NODE_TYPE_ACTION)
 		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
+			/*
+			 * 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;
 		}
 
 		from_char_set_mode(out, n->key->date_mode);
@@ -3086,10 +3178,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more charaters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3367,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e68..fb595c7b17d 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 separator character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,31 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000  +JUN', 'YYYY//MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3071,13 @@ 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 ebb196a1cfc..e9accdf30ca 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');
@@ -464,6 +476,11 @@ 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_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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edc9be92a6e..6c5c722995a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6262,9 +6262,10 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces in the beginng of input string, before and
+       after patterns unless the <literal>FX</literal> option is used.  For example,
+       <literal>to_timestamp('&nbsp;2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000 - JUN', 'YYYY-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
@@ -6272,6 +6273,39 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       Space or separator (non letter and non digit character) in the formatting string of
+       <function>to_timestamp</function> and <function>to_date</function>
+       matches to nothing or one space or separator in the input string
+       unless the <literal>FX</literal> option is used.
+       <literal>to_timestamp('2000JUN', '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 separators in the input string
+       doesn't match count of it in the formatting string.
+       When <literal>FX</literal> is specified then space matches only space
+       and separator matches only the same separator.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       <literal>TZH</literal> template pattern may match signed number.  When
+       <literal>FX</literal> option isn't used that may lead to an ambiguity in
+       interpreting of minus sign, which may be also interpreted as separator.
+       This ambiguity is resolving as following.  When number of spaces and
+       separators before minus sign in input string is greater or equal to the
+       number of spaces and separators before <literal>TZH</literal> in formatting
+       string, then this minus is interpreted as part of time-zone hours.
+       Otherwise minus sign is considered as separator between values.
+       <literal>to_timestamp('2000 -10', 'YYYY TZH')</literal> matches
+       <literal>-10</literal> to <literal>TZH</literal>, but
+       <literal>to_timestamp('2000 -10', 'YYYY&nbsp;&nbsp;TZH')</literal>
+       matches just <literal>10</literal> to <literal>TZH</literal>
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        Ordinary text is allowed in <function>to_char</function>
@@ -6287,6 +6321,20 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 12 it was possible to
+          skip input ordinary text using non letter and non digit characters.
+          For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> worked
+          before.  But currently to skip ordinary text in the input string it
+          is necessary to use only letter characters.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> or
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal> will
+          skip <literal>y</literal>, <literal>m</literal> and
+          <literal>d</literal> now.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575d..f5b692a0d9a 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,25 +3007,69 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped charaters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces in the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we don't insist that the consumed
+			 * character matches the format's character.
 			 */
-			s += pg_mblen(s);
+			if (!fx_mode)
+			{
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+			}
+			else
+			{
+				/*
+				 * In FX mode we insist that whitespaces and separator
+				 * characters from the format string match the same in input
+				 * string.
+				 */
+				if ((n->type == NODE_TYPE_SPACE && !isspace((unsigned char) *s)) ||
+					(n->type == NODE_TYPE_SEPARATOR && *n->character != *s))
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+							 errmsg("unexpected character \"%.*s\", expected space character \"%s\"",
+									pg_mblen(s), s, n->character),
+							 errhint("In FX mode, punctuation in the input string "
+									 "must exactly match the format string.")));
+				s++;
+			}
 			continue;
 		}
-
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
+		else if (n->type != NODE_TYPE_ACTION)
 		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
+			/*
+			 * 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;
 		}
 
 		from_char_set_mode(out, n->key->date_mode);
@@ -3086,10 +3150,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more charaters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3339,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e68..63fb1c44fe9 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 space character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,64 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+         to_timestamp         
+------------------------------
+ Sat Jan 01 02:00:00 2000 PST
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+         to_timestamp         
+------------------------------
+ Fri Dec 31 06:00:00 1999 PST
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3104,13 @@ 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 ebb196a1cfc..807037be76e 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');
@@ -464,6 +476,17 @@ 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', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+
 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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index edc9be9..a8bbafc 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6262,11 +6262,12 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces at the beginning of the input string and
+       around date and time values unless the <literal>FX</literal> option is used.  For example,
+       <literal>to_timestamp('&nbsp;2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000 - JUN', 'YYYY-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.
+       because <function>to_timestamp</function> expects a single space only.
        <literal>FX</literal> must be specified as the first item in
        the template.
       </para>
@@ -6274,6 +6275,43 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
 
      <listitem>
       <para>
+       A separator (a space or a non-letter/non-digit character) in the template string of
+       <function>to_timestamp</function> and <function>to_date</function>
+       matches any single separator in the input string or is skipped,
+       unless the <literal>FX</literal> option is used.
+       For example, <literal>to_timestamp('2000JUN', '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 the number of separators in the input string
+       exceeds the number of separators in the template.
+      </para>
+      <para>
+       If <literal>FX</literal> is specified, separators in the
+       input and template strings must match exactly. For example,
+       <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
+       returns an error because a space is expected in the input string.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       <literal>TZH</literal> template pattern can match a signed number.
+       Without the <literal>FX</literal> option, it may lead to ambiguity in
+       interpretation of the minus sign, which can also be interpreted as a separator.
+       This ambiguity is resolved as follows.  If the number of separators before
+       <literal>TZH</literal> in the template string is less than the number of
+       separators before the minus sign in the input string, the minus sign
+       is interpreted as part of <literal>TZH</literal>.
+       Otherwise, the minus sign is considered to be a separator between values.
+       For example, <literal>to_timestamp('2000 -10', 'YYYY TZH')</literal> matches
+       <literal>-10</literal> to <literal>TZH</literal>, but
+       <literal>to_timestamp('2000 -10', 'YYYY&nbsp;&nbsp;TZH')</literal>
+       matches <literal>10</literal> to <literal>TZH</literal>.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
        Ordinary text is allowed in <function>to_char</function>
        templates and will be output literally.  You can put a substring
        in double quotes to force it to be interpreted as literal text
@@ -6287,6 +6325,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 12, it was possible to
+          skip arbitrary text in the input string using non-letter or non-digit
+          characters. For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> used to
+          work.  Now you can only use letter characters for this purpose.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> and
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal>
+          skip <literal>y</literal>, <literal>m</literal>, and
+          <literal>d</literal>.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3..bf4e606 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,25 +3007,69 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped characters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces at the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we don't insist that the consumed
+			 * character matches the format's character.
 			 */
-			s += pg_mblen(s);
+			if (!fx_mode)
+			{
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+			}
+			else
+			{
+				/*
+				 * In FX mode we insist that whitespaces and separator
+				 * characters from the format string match the same in input
+				 * string.
+				 */
+				if ((n->type == NODE_TYPE_SPACE && !isspace((unsigned char) *s)) ||
+					(n->type == NODE_TYPE_SEPARATOR && *n->character != *s))
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+							 errmsg("unexpected character \"%.*s\", expected character \"%s\"",
+									pg_mblen(s), s, n->character),
+							 errhint("In FX mode, punctuation in the input string "
+									 "must exactly match the format string.")));
+				s++;
+			}
 			continue;
 		}
-
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
+		else if (n->type != NODE_TYPE_ACTION)
 		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
+			/*
+			 * 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;
 		}
 
 		from_char_set_mode(out, n->key->date_mode);
@@ -3086,10 +3150,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more characters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3339,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e3919..976f478 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
@@ -2810,6 +2828,21 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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 character ":"
+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         
 ------------------------------
@@ -2966,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3029,64 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+         to_timestamp         
+------------------------------
+ Sat Jan 01 02:00:00 2000 PST
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+         to_timestamp         
+------------------------------
+ Fri Dec 31 06:00:00 1999 PST
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3104,13 @@ 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 ebb196a..807037b 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');
@@ -464,6 +476,17 @@ 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', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+
 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');

diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e68..e585b07c18c 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         
+------------------------------
+ Wed Jan 02 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
@@ -2810,6 +2828,24 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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');
+         to_timestamp         
+------------------------------
+ Sun Feb 16 00:00:00 1997 PST
+(1 row)
+
+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         
 ------------------------------
@@ -2999,6 +3035,48 @@ SELECT to_timestamp('2011-12-18  23:38:15', 'YYYY-MM-DD   HH24:MI:SS');
  Sun Dec 18 03:38:15 2011 PST
 (1 row)
 
+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:  invalid value "+JU" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+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:  invalid value "+JU" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + JUN', 'YYYY MON');
+ERROR:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 ++ JUN', 'YYYY  MON');
+ERROR:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+ERROR:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+ERROR:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+         to_timestamp         
+------------------------------
+ Sat Jan 01 02:00:00 2000 PST
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+         to_timestamp         
+------------------------------
+ Fri Dec 31 06:00:00 1999 PST
+(1 row)
+
 SELECT to_date('2011 12  18', 'YYYY MM DD');
   to_date   
 ------------
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index ebb196a1cfc..807037be76e 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');
@@ -464,6 +476,17 @@ 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', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+
 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');

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index bb794e044f4..6f28fe1e753 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6262,16 +6262,54 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces at the beginning of the input string and
+       around date and time values unless the <literal>FX</literal> option is used.  For example,
+       <literal>to_timestamp('&nbsp;2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000 - JUN', 'YYYY-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.
+       because <function>to_timestamp</function> expects a single space only.
        <literal>FX</literal> must be specified as the first item in
        the template.
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       A separator (a space or a non-letter/non-digit character) in the template string of
+       <function>to_timestamp</function> and <function>to_date</function>
+       matches any single separator in the input string or is skipped,
+       unless the <literal>FX</literal> option is used.
+       For example, <literal>to_timestamp('2000JUN', '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 the number of separators in the input string
+       exceeds the number of separators in the template.
+      </para>
+      <para>
+       If <literal>FX</literal> is specified, separators in the
+       input and template strings must match exactly. For example,
+       <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
+       returns an error because a space is expected in the input string.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       <literal>TZH</literal> template pattern can match a signed number.
+       Without the <literal>FX</literal> option, it may lead to ambiguity in
+       interpretation of the minus sign, which can also be interpreted as a separator.
+       This ambiguity is resolved as follows.  If the number of separators before
+       <literal>TZH</literal> in the template string is less than the number of
+       separators before the minus sign in the input string, the minus sign
+       is interpreted as part of <literal>TZH</literal>.
+       Otherwise, the minus sign is considered to be a separator between values.
+       For example, <literal>to_timestamp('2000 -10', 'YYYY TZH')</literal> matches
+       <literal>-10</literal> to <literal>TZH</literal>, but
+       <literal>to_timestamp('2000 -10', 'YYYY&nbsp;&nbsp;TZH')</literal>
+       matches <literal>10</literal> to <literal>TZH</literal>.
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        Ordinary text is allowed in <function>to_char</function>
@@ -6287,6 +6325,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 12, it was possible to
+          skip arbitrary text in the input string using non-letter or non-digit
+          characters. For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> used to
+          work.  Now you can only use letter characters for this purpose.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> and
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal>
+          skip <literal>y</literal>, <literal>m</literal>, and
+          <literal>d</literal>.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575d..bf4e6067e85 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,25 +3007,69 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped characters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces at the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
 		{
 			/*
-			 * Separator, so consume one character from input string.  Notice
-			 * we don't insist that the consumed character match the format's
-			 * character.
+			 * In non FX (fixed format) mode we don't insist that the consumed
+			 * character matches the format's character.
 			 */
-			s += pg_mblen(s);
+			if (!fx_mode)
+			{
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+			}
+			else
+			{
+				/*
+				 * In FX mode we insist that whitespaces and separator
+				 * characters from the format string match the same in input
+				 * string.
+				 */
+				if ((n->type == NODE_TYPE_SPACE && !isspace((unsigned char) *s)) ||
+					(n->type == NODE_TYPE_SEPARATOR && *n->character != *s))
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
+							 errmsg("unexpected character \"%.*s\", expected character \"%s\"",
+									pg_mblen(s), s, n->character),
+							 errhint("In FX mode, punctuation in the input string "
+									 "must exactly match the format string.")));
+				s++;
+			}
 			continue;
 		}
-
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
+		else if (n->type != NODE_TYPE_ACTION)
 		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
+			/*
+			 * 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;
 		}
 
 		from_char_set_mode(out, n->key->date_mode);
@@ -3086,10 +3150,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more characters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3339,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index e585b07c18c..976f4783e1e 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2790,7 +2790,7 @@ SELECT to_timestamp('1985 FMMonth 12', 'YYYY "FMMonth" DD');
 SELECT to_timestamp('1985 \ 12', 'YYYY \\ DD');
          to_timestamp         
 ------------------------------
- Wed Jan 02 00:00:00 1985 PST
+ Sat Jan 12 00:00:00 1985 PST
 (1 row)
 
 SELECT to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16',
@@ -2835,11 +2835,8 @@ SELECT to_timestamp('97/Feb/16', 'YY:Mon:DD');
 (1 row)
 
 SELECT to_timestamp('97/Feb/16', 'FXYY:Mon:DD');
-         to_timestamp         
-------------------------------
- Sun Feb 16 00:00:00 1997 PST
-(1 row)
-
+ERROR:  unexpected character "/", expected character ":"
+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         
 ------------------------------
@@ -3002,7 +2999,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -3032,7 +3029,7 @@ 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');
@@ -3042,8 +3039,11 @@ SELECT to_timestamp('2000+   JUN', 'YYYY/MON');
 (1 row)
 
 SELECT to_timestamp('  2000 +JUN', 'YYYY/MON');
-ERROR:  invalid value "+JU" for "MON"
-DETAIL:  The given value did not match any of the allowed values for this field.
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
 SELECT to_timestamp(' 2000 +JUN', 'YYYY//MON');
          to_timestamp         
 ------------------------------
@@ -3051,20 +3051,32 @@ SELECT to_timestamp(' 2000 +JUN', 'YYYY//MON');
 (1 row)
 
 SELECT to_timestamp('2000  +JUN', 'YYYY//MON');
-ERROR:  invalid value "+JU" for "MON"
-DETAIL:  The given value did not match any of the allowed values for this field.
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
 SELECT to_timestamp('2000 + JUN', 'YYYY MON');
-ERROR:  invalid value "+ J" for "MON"
-DETAIL:  The given value did not match any of the allowed values for this field.
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
 SELECT to_timestamp('2000 ++ JUN', 'YYYY  MON');
-ERROR:  invalid value "+ J" for "MON"
-DETAIL:  The given value did not match any of the allowed values for this field.
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
 SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
 ERROR:  invalid value "+ J" for "MON"
 DETAIL:  The given value did not match any of the allowed values for this field.
 SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
-ERROR:  invalid value "+ J" for "MON"
-DETAIL:  The given value did not match any of the allowed values for this field.
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
 SELECT to_timestamp('2000 -10', 'YYYY TZH');
          to_timestamp         
 ------------------------------
@@ -3092,13 +3104,13 @@ 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');

commit a5f933a84627f442d1850ca6da642be7fdb660ea
Author: Alexander Korotkov <akorotkov@postgresql.org>
Date:   Tue Sep 4 00:02:30 2018 +0300

    Improve behavior of to_timestamp()/to_date() functions
    
    to_timestamp()/to_date() functions were introduced mainly for Oracle
    compatibility, and became very popular among PostgreSQL users.  However, some
    behavior of to_timestamp()/to_date() functions are both incompatible with Oracle
    and confusing for our users.  This behavior is related to handling of spaces and
    separators in non FX (fixed format) mode.  This commit reworks this behavior
    making less confusing, better documented and more compatible with Oracle.
    
    Nevertheless, there are still following incompatibilities with Oracle.
    1) We don't insist that there are no format string patterns unmatched to
       input string.
    2) In FX mode we don't exist space and separators in format string to exactly
       match input string.
    3) When format string patterns are divided by mix of spaces and separators, we
       don't distinguish them, while Oracle takes into account only last group of
       spaces/separators.
    
    Discussion: https://postgr.es/m/1873520224.1784572.1465833145330.JavaMail.yahoo%40mail.yahoo.com
    Author: Artur Zakirov, Alexander Korotkov, Liudmila Mantrova
    Review: Amul Sul, Robert Haas, Tom Lane, Dmitry Dolgov, David G. Johnston

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index bb794e044f4..3f15dc57282 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6262,16 +6262,57 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces at the beginning of the input string and
+       around date and time values unless the <literal>FX</literal> option is used.  For example,
+       <literal>to_timestamp('&nbsp;2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000 - JUN', 'YYYY-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.
+       because <function>to_timestamp</function> expects a single space only.
        <literal>FX</literal> must be specified as the first item in
        the template.
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       A separator (a space or a non-letter/non-digit character) in the template string of
+       <function>to_timestamp</function> and <function>to_date</function>
+       matches any single separator in the input string or is skipped,
+       unless the <literal>FX</literal> option is used.
+       For example, <literal>to_timestamp('2000JUN', '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 the number of separators in the input string
+       exceeds the number of separators in the template.
+      </para>
+      <para>
+       If <literal>FX</literal> is specified, separator in template string
+       matches to exactly one character in input string.  Notice we don't insist
+       input string character to be the same as template string separator.
+       For example, <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
+       works, but <literal>to_timestamp('2000/JUN', 'FXYYYY  MON')</literal>
+       returns an error because a space second template string space consumed
+       letter <literal>J</literal> from the input string.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       <literal>TZH</literal> template pattern can match a signed number.
+       Without the <literal>FX</literal> option, it may lead to ambiguity in
+       interpretation of the minus sign, which can also be interpreted as a separator.
+       This ambiguity is resolved as follows.  If the number of separators before
+       <literal>TZH</literal> in the template string is less than the number of
+       separators before the minus sign in the input string, the minus sign
+       is interpreted as part of <literal>TZH</literal>.
+       Otherwise, the minus sign is considered to be a separator between values.
+       For example, <literal>to_timestamp('2000 -10', 'YYYY TZH')</literal> matches
+       <literal>-10</literal> to <literal>TZH</literal>, but
+       <literal>to_timestamp('2000 -10', 'YYYY&nbsp;&nbsp;TZH')</literal>
+       matches <literal>10</literal> to <literal>TZH</literal>.
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        Ordinary text is allowed in <function>to_char</function>
@@ -6287,6 +6328,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 12, it was possible to
+          skip arbitrary text in the input string using non-letter or non-digit
+          characters. For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> used to
+          work.  Now you can only use letter characters for this purpose.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> and
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal>
+          skip <literal>y</literal>, <literal>m</literal>, and
+          <literal>d</literal>.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575d..2ed8ca675bd 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,27 +3007,66 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped characters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces at the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
+		{
+			if (!fx_mode)
+			{
+				/*
+				 * In non FX (fixed format) mode one format string space or
+				 * separator match to one space or separator in input string.
+				 * Or match nothing if there is no space or separator in
+				 * the current position of input string.
+				 */
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+			}
+			else
+			{
+				/*
+				 * In FX mode, on format string space or separator we consume
+				 * exactly one character from input string.  Notice we don't
+				 * insist that the consumed character match the format's
+				 * character.
+				 */
+				s += pg_mblen(s);
+			}
+			continue;
+		}
+		else if (n->type != NODE_TYPE_ACTION)
 		{
 			/*
-			 * 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;
 		}
 
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
-		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
-		}
-
 		from_char_set_mode(out, n->key->date_mode);
 
 		switch (n->key->id)
@@ -3086,10 +3145,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more characters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3334,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e68..7d11f251584 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
@@ -2810,6 +2828,24 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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');
+         to_timestamp         
+------------------------------
+ Sun Feb 16 00:00:00 1997 PST
+(1 row)
+
+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         
 ------------------------------
@@ -2966,7 +3002,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3032,64 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+         to_timestamp         
+------------------------------
+ Sat Jan 01 02:00:00 2000 PST
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+         to_timestamp         
+------------------------------
+ Fri Dec 31 06:00:00 1999 PST
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3107,13 @@ 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 ebb196a1cfc..807037be76e 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');
@@ -464,6 +476,17 @@ 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', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+
 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');

commit 9b27411b6bbd9161ddddc3b6aa7253816df0e175
Author: Alexander Korotkov <akorotkov@postgresql.org>
Date:   Tue Sep 4 00:02:30 2018 +0300

    Improve behavior of to_timestamp()/to_date() functions
    
    to_timestamp()/to_date() functions were introduced mainly for Oracle
    compatibility, and became very popular among PostgreSQL users.  However, some
    behavior of to_timestamp()/to_date() functions are both incompatible with Oracle
    and confusing for our users.  This behavior is related to handling of spaces and
    separators in non FX (fixed format) mode.  This commit reworks this behavior
    making less confusing, better documented and more compatible with Oracle.
    
    Nevertheless, there are still following incompatibilities with Oracle.
    1) We don't insist that there are no format string patterns unmatched to
       input string.
    2) In FX mode we don't exist space and separators in format string to exactly
       match input string.
    3) When format string patterns are divided by mix of spaces and separators, we
       don't distinguish them, while Oracle takes into account only last group of
       spaces/separators.
    
    Discussion: https://postgr.es/m/1873520224.1784572.1465833145330.JavaMail.yahoo%40mail.yahoo.com
    Author: Artur Zakirov, Alexander Korotkov, Liudmila Mantrova
    Review: Amul Sul, Robert Haas, Tom Lane, Dmitry Dolgov, David G. Johnston

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index bb794e044f4..9b8a0134846 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6262,16 +6262,57 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
      <listitem>
       <para>
        <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
+       skip multiple blank spaces at the beginning of the input string and
+       around date and time values unless the <literal>FX</literal> option is used.  For example,
+       <literal>to_timestamp('&nbsp;2000&nbsp;&nbsp;&nbsp;&nbsp;JUN', 'YYYY MON')</literal> and
+       <literal>to_timestamp('2000 - JUN', 'YYYY-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.
+       because <function>to_timestamp</function> expects a single space only.
        <literal>FX</literal> must be specified as the first item in
        the template.
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       A separator (a space or a non-letter/non-digit character) in the template string of
+       <function>to_timestamp</function> and <function>to_date</function>
+       matches any single separator in the input string or is skipped,
+       unless the <literal>FX</literal> option is used.
+       For example, <literal>to_timestamp('2000JUN', '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 the number of separators in the input string
+       exceeds the number of separators in the template.
+      </para>
+      <para>
+       If <literal>FX</literal> is specified, separator in template string
+       matches to exactly one character in input string.  Notice we don't insist
+       input string character to be the same as template string separator.
+       For example, <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
+       works, but <literal>to_timestamp('2000/JUN', 'FXYYYY&nbsp;&nbsp;MON')</literal>
+       returns an error because a space second template string space consumed
+       letter <literal>J</literal> from the input string.
+      </para>
+     </listitem>
+
+     <listitem>
+      <para>
+       <literal>TZH</literal> template pattern can match a signed number.
+       Without the <literal>FX</literal> option, it may lead to ambiguity in
+       interpretation of the minus sign, which can also be interpreted as a separator.
+       This ambiguity is resolved as follows.  If the number of separators before
+       <literal>TZH</literal> in the template string is less than the number of
+       separators before the minus sign in the input string, the minus sign
+       is interpreted as part of <literal>TZH</literal>.
+       Otherwise, the minus sign is considered to be a separator between values.
+       For example, <literal>to_timestamp('2000 -10', 'YYYY TZH')</literal> matches
+       <literal>-10</literal> to <literal>TZH</literal>, but
+       <literal>to_timestamp('2000 -10', 'YYYY&nbsp;&nbsp;TZH')</literal>
+       matches <literal>10</literal> to <literal>TZH</literal>.
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        Ordinary text is allowed in <function>to_char</function>
@@ -6287,6 +6328,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
        string; for example <literal>"XX"</literal> skips two input characters
        (whether or not they are <literal>XX</literal>).
       </para>
+      <tip>
+        <para>
+          Prior to <productname>PostgreSQL</productname> 12, it was possible to
+          skip arbitrary text in the input string using non-letter or non-digit
+          characters. For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyy-MM-DD')</literal> used to
+          work.  Now you can only use letter characters for this purpose.  For example,
+          <literal>to_timestamp('2000y6m1d', 'yyyytMMtDDt')</literal> and
+          <literal>to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</literal>
+          skip <literal>y</literal>, <literal>m</literal>, and
+          <literal>d</literal>.
+        </para>
+      </tip>
      </listitem>
 
      <listitem>
diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c
index 30696e3575d..2ed8ca675bd 100644
--- a/src/backend/utils/adt/formatting.c
+++ b/src/backend/utils/adt/formatting.c
@@ -165,6 +165,8 @@ 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
@@ -955,6 +957,7 @@ 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);
@@ -1044,6 +1047,16 @@ 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
  * ----------
@@ -1319,7 +1332,14 @@ 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;
@@ -2987,27 +3007,66 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 	int			len,
 				value;
 	bool		fx_mode = false;
+	/* number of extra skipped characters (more than given in format string) */
+	int			extra_skip = 0;
 
 	for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++)
 	{
-		if (n->type != NODE_TYPE_ACTION)
+		/*
+		 * Ignore spaces at the beginning of the string and before fields when
+		 * not in FX (fixed width) mode.
+		 */
+		if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) &&
+			(n->type == NODE_TYPE_ACTION || n == node))
+		{
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
+
+		if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR)
+		{
+			if (!fx_mode)
+			{
+				/*
+				 * In non FX (fixed format) mode one format string space or
+				 * separator match to one space or separator in input string.
+				 * Or match nothing if there is no space or separator in
+				 * the current position of input string.
+				 */
+				extra_skip--;
+				if (isspace((unsigned char) *s) || is_separator_char(s))
+				{
+					s++;
+					extra_skip++;
+				}
+			}
+			else
+			{
+				/*
+				 * In FX mode, on format string space or separator we consume
+				 * exactly one character from input string.  Notice we don't
+				 * insist that the consumed character match the format's
+				 * character.
+				 */
+				s += pg_mblen(s);
+			}
+			continue;
+		}
+		else if (n->type != NODE_TYPE_ACTION)
 		{
 			/*
-			 * 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;
 		}
 
-		/* Ignore spaces before fields when not in FX (fixed width) mode */
-		if (!fx_mode && n->key->id != DCH_FX)
-		{
-			while (*s != '\0' && isspace((unsigned char) *s))
-				s++;
-		}
-
 		from_char_set_mode(out, n->key->date_mode);
 
 		switch (n->key->id)
@@ -3086,10 +3145,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 								n->key->name)));
 				break;
 			case DCH_TZH:
-				out->tzsign = *s == '-' ? -1 : +1;
-
+				/*
+				 * Value of TZH might be negative.  And the issue is that we
+				 * might swallow minus sign as the separator.  So, if we have
+				 * skipped more characters than specified in the format string,
+				 * then we consider prepending last skipped minus to TZH.
+				 */
 				if (*s == '+' || *s == '-' || *s == ' ')
+				{
+					out->tzsign = *s == '-' ? -1 : +1;
 					s++;
+				}
+				else
+				{
+					if (extra_skip > 0 && *(s - 1) == '-')
+						out->tzsign = -1;
+					else
+						out->tzsign = +1;
+				}
 
 				from_char_parse_int_len(&out->tzh, &s, 2, n);
 				break;
@@ -3261,6 +3334,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out)
 				SKIP_THth(s, n->suffix);
 				break;
 		}
+
+		/* Ignore all spaces after fields */
+		if (!fx_mode)
+		{
+			extra_skip = 0;
+			while (*s != '\0' && isspace((unsigned char) *s))
+			{
+				s++;
+				extra_skip++;
+			}
+		}
 	}
 }
 
diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index 63e39198e68..7d11f251584 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
@@ -2810,6 +2828,24 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay');
 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.
+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');
+         to_timestamp         
+------------------------------
+ Sun Feb 16 00:00:00 1997 PST
+(1 row)
+
+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         
 ------------------------------
@@ -2966,7 +3002,7 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 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');
@@ -2996,7 +3032,64 @@ 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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+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:  invalid value "+ J" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+         to_timestamp         
+------------------------------
+ Thu Jun 01 00:00:00 2000 PDT
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+         to_timestamp         
+------------------------------
+ Sat Jan 01 02:00:00 2000 PST
+(1 row)
+
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+         to_timestamp         
+------------------------------
+ Fri Dec 31 06:00:00 1999 PST
 (1 row)
 
 SELECT to_date('2011 12  18', 'YYYY MM DD');
@@ -3014,13 +3107,13 @@ 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 ebb196a1cfc..807037be76e 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');
@@ -464,6 +476,17 @@ 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', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY  MON');
+SELECT to_timestamp('2000 + + JUN', 'YYYY   MON');
+SELECT to_timestamp('2000 -10', 'YYYY TZH');
+SELECT to_timestamp('2000 -10', 'YYYY  TZH');
+
 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');