Fixed LP bug #817360.

This problem could be observed for queries with nested outer joins
for which the not_exist optimization were applicable. 
The problem was caused by the code of the patch for bug #49322
that erroneously forced the return to the previous nested loop
level when the join algorithm successfully builds a partial record
for an embedded outer to which the not_exist optimization could be
applied.
Actually the immediate return to the previous nested loops level
is correct only if this partial record is rejected by a predicate
pushed down to one of the inner tables of this outer join. Otherwise
attempts to find extensions of this record must be made.

1 files changed, 31 insertions, 0 deletions

diff --git a/mysql-test/r/join_nested.result b/mysql-test/r/join_nested.result
index 0b1fdf8d0bb..bdf650b97bc 100644
--- a/mysql-test/r/join_nested.result
+++ b/mysql-test/r/join_nested.result
@@ -1801,4 +1801,35 @@ pk	a	pk	a	pk	a
 7	NULL	NULL	NULL	NULL	NULL
 8	9	NULL	NULL	NULL	NULL
 DROP TABLE t1, t2, t3;
+CREATE TABLE t1 (a int NOT NULL );
+INSERT INTO t1 VALUES (9), (9);
+CREATE TABLE t2 (a int NOT NULL );
+INSERT INTO t2 VALUES (9);
+CREATE TABLE t3 (a int NOT NULL, b int);
+INSERT INTO t3 VALUES (19,9);
+CREATE TABLE t4 (b int) ;
+SELECT * FROM t1 LEFT JOIN
+((t2 LEFT JOIN t3 ON t2.a=t3.b) LEFT JOIN t4 ON t3.a=t4.b)
+ON t1.a=t2.a;
+a	a	a	b	b
+9	9	19	9	NULL
+9	9	19	9	NULL
+SELECT * FROM t1 LEFT JOIN
+((t2 LEFT JOIN t3 ON t2.a=t3.b) LEFT JOIN t4 ON t3.a=t4.b)
+ON t1.a=t2.a
+WHERE t3.a IS NULL;
+a	a	a	b	b
+EXPLAIN EXTENDED
+SELECT * FROM t1 LEFT JOIN
+((t2 LEFT JOIN t3 ON t2.a=t3.b) LEFT JOIN t4 ON t3.a=t4.b)
+ON t1.a=t2.a
+WHERE t3.a IS NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1	100.00	Using where
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	1	100.00	Using where; Not exists
+1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	0.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a`,`test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t4`.`b` AS `b` from `test`.`t1` left join (`test`.`t2` left join `test`.`t3` on(((`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t3`.`b` = `test`.`t1`.`a`))) left join `test`.`t4` on((`test`.`t4`.`b` = `test`.`t3`.`a`))) on((`test`.`t2`.`a` = `test`.`t1`.`a`)) where isnull(`test`.`t3`.`a`)
+DROP TABLE t1,t2,t3,t4;
 End of 5.0 tests