Fixed a test.

mysql-test/r/change_user.result

@@ -4,14 +4,14 @@ SELECT @@session.sql_big_selects;
 1
 SELECT @@global.max_join_size;
 @@global.max_join_size
-18446744073709551615
+MAX_JOIN_SIZE
 change_user
 SELECT @@session.sql_big_selects;
 @@session.sql_big_selects
 1
 SELECT @@global.max_join_size;
 @@global.max_join_size
-18446744073709551615
+MAX_JOIN_SIZE
 SET @@global.max_join_size = 10000;
 SET @@session.max_join_size = default;
 change_user

mysql-test/t/change_user.test

@@ -4,17 +4,22 @@
 
 --echo Bug#20023
 SELECT @@session.sql_big_selects;
+--replace_result 18446744073709551615 MAX_JOIN_SIZE 4294967295 MAX_JOIN_SIZE
 SELECT @@global.max_join_size;
 --echo change_user
 --change_user
 SELECT @@session.sql_big_selects;
+--replace_result 18446744073709551615 MAX_JOIN_SIZE 4294967295 MAX_JOIN_SIZE
 SELECT @@global.max_join_size;
 SET @@global.max_join_size = 10000;
 SET @@session.max_join_size = default;
 --echo change_user
 --change_user
 SELECT @@session.sql_big_selects;
+# On some machines the following will result into a warning
+--disable_warnings
 SET @@global.max_join_size = -1;
+--enable_warnings
 SET @@session.max_join_size = default;
 --echo change_user
 --change_user

sql/mysqld.cc

@@ -308,11 +308,7 @@ TYPELIB thread_handling_typelib=
 
 const char *first_keyword= "first", *binary_keyword= "BINARY";
 const char *my_localhost= "localhost", *delayed_user= "DELAYED";
-#if SIZEOF_OFF_T > 4 && defined(BIG_TABLES)
-#define GET_HA_ROWS GET_ULL
-#else
-#define GET_HA_ROWS GET_ULONG
-#endif
+#define GET_HA_ROWS (~ (ha_rows) 0)
 
 bool opt_large_files= sizeof(my_off_t) > 4;