Fix for bug #9404: information_schema: Weird error messages with SELECT SUM() ... GROUP BY queries

heap/hp_hash.c:
  Fix for bug #9404: information_schema: Weird error messages with SELECT SUM() ... GROUP BY queries 
      use length in symbols instead of length in bytes
      to calculate record length and key length

heap/hp_hash.c

@@ -635,13 +635,12 @@ int hp_key_cmp(HP_KEYDEF *keydef, const byte *rec, const byte *key)
       key+= 2;                                  /* skip key pack length */
       if (cs->mbmaxlen > 1)
       {
-        uint char_length= seg->length / cs->mbmaxlen;
-        char_length_key= my_charpos(cs, key, key + char_length_key,
-                                    char_length);
-        set_if_smaller(char_length_key, seg->length);
-        char_length_rec= my_charpos(cs, pos, pos + char_length_rec,
-                                    char_length);
-        set_if_smaller(char_length_rec, seg->length);
+        uint char_length1, char_length2;
+        char_length1= char_length2= seg->length / cs->mbmaxlen; 
+        char_length1= my_charpos(cs, key, key + char_length_key, char_length1);
+        set_if_smaller(char_length_key, char_length1);
+        char_length2= my_charpos(cs, pos, pos + char_length_rec, char_length2);
+        set_if_smaller(char_length_rec, char_length2);
       }
 
       if (cs->coll->strnncollsp(seg->charset,

mysql-test/r/information_schema.result

@@ -734,3 +734,7 @@ x_real	NULL	NULL
 x_float	NULL	NULL
 x_double_precision	NULL	NULL
 drop table t1;
+SELECT table_schema, count(*) FROM information_schema.TABLES GROUP BY TABLE_SCHEMA;
+table_schema	count(*)
+information_schema	15
+mysql	17

mysql-test/t/information_schema.test

@@ -473,3 +473,9 @@ SELECT COLUMN_NAME, CHARACTER_MAXIMUM_LENGTH, CHARACTER_OCTET_LENGTH
 FROM INFORMATION_SCHEMA.COLUMNS
 WHERE TABLE_NAME= 't1';
 drop table t1;
+
+#
+# Bug #9404  information_schema: Weird error messages 
+# with SELECT SUM() ... GROUP BY queries
+#
+SELECT table_schema, count(*) FROM information_schema.TABLES GROUP BY TABLE_SCHEMA;