diff --git a/src/backend/utils/adt/Makefile b/src/backend/utils/adt/Makefile
index 07857543a5..7dac1e03fb 100644
--- a/src/backend/utils/adt/Makefile
+++ b/src/backend/utils/adt/Makefile
@@ -43,6 +43,7 @@ jsonpath_gram.h: jsonpath_gram.c
 jsonpath_gram.c: BISONFLAGS += -d
 
 jsonpath_scan.c: FLEXFLAGS = -CF -p -p
+jsonpath_scan.c: FLEX_NO_BACKUP=yes
 
 
 # Force these dependencies to be known even without dependency info built:
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l
index 06efe0e6ab..1df4506897 100644
--- a/src/backend/utils/adt/jsonpath_scan.l
+++ b/src/backend/utils/adt/jsonpath_scan.l
@@ -71,9 +71,20 @@ fprintf_to_ereport(const char *fmt, const char *msg)
 special		 [\?\%\$\.\[\]\{\}\(\)\|\&\!\=\<\>\@\#\,\*:\-\+\/]
 any			[^\?\%\$\.\[\]\{\}\(\)\|\&\!\=\<\>\@\#\,\*:\-\+\/\\\"\' \t\n\r\f]
 blank		[ \t\n\r\f]
+
+digit		[0-9]
+integer		{digit}+
+decimal		{digit}*\.{digit}+
+decimalfail	{digit}+\.
+real		({integer}|{decimal})[Ee][-+]?{digit}+
+realfail1	({integer}|{decimal})[Ee]
+realfail2	({integer}|{decimal})[Ee][-+]
+
 hex_dig		[0-9A-Fa-f]
 unicode		\\u({hex_dig}{4}|\{{hex_dig}{1,6}\})
+unicodefail	\\u({hex_dig}{0,3}|\{{hex_dig}{0,6})
 hex_char	\\x{hex_dig}{2}
+hex_fail	\\x{hex_dig}{0,1}
 
 
 %%
@@ -121,28 +132,30 @@ hex_char	\\x{hex_dig}{2}
 									BEGIN xCOMMENT;
 								}
 
-<INITIAL>[0-9]+(\.[0-9]+)?[eE][+-]?[0-9]+  /* float */  {
+<INITIAL>{real}					{
 									addstring(true, yytext, yyleng);
 									addchar(false, '\0');
 									yylval->str = scanstring;
 									return NUMERIC_P;
 								}
 
-<INITIAL>\.[0-9]+[eE][+-]?[0-9]+  /* float */  {
+<INITIAL>{decimal}				{
 									addstring(true, yytext, yyleng);
 									addchar(false, '\0');
 									yylval->str = scanstring;
 									return NUMERIC_P;
 								}
 
-<INITIAL>([0-9]+)?\.[0-9]+		{
+<INITIAL>{integer}				{
 									addstring(true, yytext, yyleng);
 									addchar(false, '\0');
 									yylval->str = scanstring;
-									return NUMERIC_P;
+									return INT_P;
 								}
 
-<INITIAL>[0-9]+					{
+<INITIAL>{decimalfail}			{
+									/* throw back the ., and treat as integer */
+									yyless(yyleng - 1);
 									addstring(true, yytext, yyleng);
 									addchar(false, '\0');
 									yylval->str = scanstring;
@@ -199,6 +212,8 @@ hex_char	\\x{hex_dig}{2}
 									return checkSpecialVal();
 								}
 
+<INITIAL>({realfail1}|{realfail2})	{ yyerror(NULL, "Floating point number is invalid"); }
+
 <xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\[\"\'\\]	{ addchar(false, yytext[1]); }
 
 <xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\b	{ addchar(false, '\b'); }
@@ -213,13 +228,13 @@ hex_char	\\x{hex_dig}{2}
 
 <xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\v	{ addchar(false, '\v'); }
 
-<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{unicode}+		{ parseUnicode(yytext, yyleng); }
+<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{unicode}		{ parseUnicode(yytext, yyleng); }
 
-<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{hex_char}+	{ parseHexChars(yytext, yyleng); }
+<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{hex_char}		{ parseHexChars(yytext, yyleng); }
 
-<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\x	{ yyerror(NULL, "Hex character sequence is invalid"); }
+<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{hex_fail}	{ yyerror(NULL, "Hex character sequence is invalid"); }
 
-<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\u	{ yyerror(NULL, "Unicode sequence is invalid"); }
+<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{unicodefail}	{ yyerror(NULL, "Unicode sequence is invalid"); }
 
 <xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\.	{ yyerror(NULL, "Escape sequence is invalid"); }