Fix for BUG#7266.

mysql-test/r/greedy_optimizer.result

@@ -129,7 +129,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	821.838037
+Last_query_cost	821.837037
 explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
@@ -141,7 +141,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	821.838037
+Last_query_cost	821.837037
 explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
@@ -153,7 +153,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	794.838037
+Last_query_cost	794.837037
 explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
@@ -165,7 +165,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	794.838037
+Last_query_cost	794.837037
 explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
@@ -177,7 +177,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	794.838037
+Last_query_cost	794.837037
 explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
@@ -189,7 +189,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
 show status like 'Last_query_cost';
 Variable_name	Value
-Last_query_cost	794.838037
+Last_query_cost	794.837037
 set optimizer_prune_level=0;
 select @@optimizer_prune_level;
 @@optimizer_prune_level

sql/sql_select.cc

@@ -4252,7 +4252,7 @@ find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
     {
       memcpy((gptr) join->best_positions,(gptr) join->positions,
 	     sizeof(POSITION)*idx);
-      join->best_read=read_time;
+      join->best_read= read_time - 0.001;
     }
     return;
   }