Fix bug lp:817384

This bug is a special case of lp:813447.

Analysis:
Constant optimization finds that the condition t2.a = 1
can be used to access the primary key of table 't2'. As
a result both outer table t1,t2 are considered as constant
when we reach the execution phase. At the same time, during
constant optimization, the IN predicate is not evaluated
because it is expensive.

When execution of the outer query reaches do_select(),
control flow enter the branch:
if (join->table_count == join->const_tables)
{ ... }
This branch checks only the WHERE and HAVING clauses,
but doesn't check the ON clauses of the query. Since the
IN predicate was not evaluated during optimization, it is
not evaluated at all, thus execution doesn't detect that
the ON clause is FALSE.

Solution:
Similar to the patch for bug lp:813447, exclude system
tables from constant substitution based on unique key
lookups if there is an expensive ON condition on the
inner table.

1 files changed, 2 insertions, 2 deletions

diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result
index ce1d97a77f7..f3bb3f6ff46 100644
--- a/mysql-test/r/subselect_no_semijoin.result
+++ b/mysql-test/r/subselect_no_semijoin.result
@@ -2961,7 +2961,7 @@ ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899'
              ORDER BY t2.c DESC, t2.b DESC LIMIT 1) WHERE t1.a = 10;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	system	PRIMARY	NULL	NULL	NULL	1	
-1	PRIMARY	r	const	PRIMARY	PRIMARY	4	const	1	
+1	PRIMARY	r	eq_ref	PRIMARY	PRIMARY	4	const	1	Using where
 2	DEPENDENT SUBQUERY	t2	range	b	b	40	NULL	2	Using index condition
 SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r
 ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899'
@@ -2973,7 +2973,7 @@ ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899'
             ORDER BY t2.c, t2.b LIMIT 1) WHERE t1.a = 10;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	system	PRIMARY	NULL	NULL	NULL	1	
-1	PRIMARY	r	const	PRIMARY	PRIMARY	4	const	1	
+1	PRIMARY	r	eq_ref	PRIMARY	PRIMARY	4	const	1	Using where
 2	DEPENDENT SUBQUERY	t2	range	b	b	40	NULL	2	Using index condition
 SELECT sql_no_cache t1.a, r.a, r.b FROM t1 LEFT JOIN t2 r
 ON r.a = (SELECT t2.a FROM t2 WHERE t2.c = t1.a AND t2.b <= '359899'