Fixed length estimate for REPLACE()

mysql-test/main/func_str.result

@@ -211,6 +211,11 @@ this	is 	test
 select replace('aaaa','a','b'),replace('aaaa','aa','b'),replace('aaaa','a','bb'),replace('aaaa','','b'),replace('bbbb','a','c');
 replace('aaaa','a','b')	replace('aaaa','aa','b')	replace('aaaa','a','bb')	replace('aaaa','','b')	replace('bbbb','a','c')
 bbbb	bb	bbbbbbbb	aaaa	bbbb
+select replace('aaaa','a','bbbb');
+Catalog	Database	Table	Table_alias	Column	Column_alias	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def					replace('aaaa','a','bbbb')	253	16	16	Y	0	39	8
+replace('aaaa','a','bbbb')
+bbbbbbbbbbbbbbbb
 select replace(concat(lcase(concat('THIS',' ','IS',' ','A',' ')),ucase('false'),' ','test'),'FALSE','REAL') ;
 replace(concat(lcase(concat('THIS',' ','IS',' ','A',' ')),ucase('false'),' ','test'),'FALSE','REAL')
 this is a REAL test

mysql-test/main/func_str.test

@@ -91,6 +91,9 @@ SELECT CONCAT('"',CONCAT_WS('";"',repeat('a',60),repeat('b',60),repeat('c',60),r
 
 select insert('txs',2,1,'hi'),insert('is ',4,0,'a'),insert('txxxxt',2,4,'es');
 select replace('aaaa','a','b'),replace('aaaa','aa','b'),replace('aaaa','a','bb'),replace('aaaa','','b'),replace('bbbb','a','c');
+--enable_metadata
+select replace('aaaa','a','bbbb');
+--disable_metadata
 select replace(concat(lcase(concat('THIS',' ','IS',' ','A',' ')),ucase('false'),' ','test'),'FALSE','REAL') ;
 select soundex(''),soundex('he'),soundex('hello all folks'),soundex('#3556 in bugdb');
 select 'mood' sounds like 'mud';

mysql-test/main/null.result

@@ -267,7 +267,7 @@ t1	CREATE TABLE `t1` (
   `c30` varchar(317) CHARACTER SET latin2 DEFAULT NULL,
   `c31` varchar(192) CHARACTER SET latin2 DEFAULT NULL,
   `c32` char(0) CHARACTER SET latin2 DEFAULT NULL,
-  `c33` varchar(3) CHARACTER SET latin2 DEFAULT NULL,
+  `c33` varchar(6) CHARACTER SET latin2 DEFAULT NULL,
   `c34` varchar(3) CHARACTER SET latin2 DEFAULT NULL,
   `c35` varchar(3) CHARACTER SET latin2 DEFAULT NULL,
   `c36` varchar(3) CHARACTER SET latin2 DEFAULT NULL,

sql/item_strfunc.cc

@@ -1286,10 +1286,10 @@ String *Item_func_replace::val_str_internal(String *str,
 bool Item_func_replace::fix_length_and_dec()
 {
   ulonglong char_length= (ulonglong) args[0]->max_char_length();
-  int diff=(int) (args[2]->max_char_length() - args[1]->max_char_length());
-  if (diff > 0 && args[1]->max_char_length())
+  int diff=(int) (args[2]->max_char_length() - 1);
+  if (diff > 0)
   {						// Calculate of maxreplaces
-    ulonglong max_substrs= char_length / args[1]->max_char_length();
+    ulonglong max_substrs= char_length;
     char_length+= max_substrs * (uint) diff;
   }