Merge bk-internal:/home/bk/mysql-5.1-opt

into  magare.gmz:/home/kgeorge/mysql/work/B30393-5.1-opt

mysql-test/r/group_by.result

@@ -1129,7 +1129,7 @@ ERROR 42000: You have an error in your SQL syntax; check the manual that corresp
 EXPLAIN SELECT a FROM t1 USE INDEX FOR JOIN (i2) 
 USE INDEX FOR GROUP BY (i2) GROUP BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index	NULL	i2	9	NULL	144	Using index
+1	SIMPLE	t1	#	NULL	i2	#	NULL	#	#
 EXPLAIN SELECT a FROM t1 FORCE INDEX FOR JOIN (i2) 
 FORCE INDEX FOR GROUP BY (i2) GROUP BY a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/t/group_by.test

@@ -828,6 +828,11 @@ EXPLAIN SELECT a FROM t1 USE INDEX (i2) USE INDEX ();
 EXPLAIN SELECT a FROM t1 FORCE INDEX ();
 --error ER_PARSE_ERROR
 EXPLAIN SELECT a FROM t1 IGNORE INDEX ();
+# disable the columns irrelevant to this test here. On some systems 
+# without support for large files the rowid is shorter and its size affects 
+# the cost calculations. This causes the optimizer to choose loose index
+# scan over normal index access.
+--replace_column 4 # 7 # 9 # 10 #
 EXPLAIN SELECT a FROM t1 USE INDEX FOR JOIN (i2) 
   USE INDEX FOR GROUP BY (i2) GROUP BY a;
 EXPLAIN SELECT a FROM t1 FORCE INDEX FOR JOIN (i2)