Fixed MDEV-13994 Bad join results with orderby_uses_equalities=on.

This patch effectively blocks the optimization that uses multiple
equalities for ORDER BY to remove tmp table in the case when
the first table happens to be the result of materialization of
a semi-join nest. Currently there is no code at the execution level
that would support the optimization in this case.

1 files changed, 48 insertions, 0 deletions

diff --git a/mysql-test/r/order_by.result b/mysql-test/r/order_by.result
index f43e6ce18af..5a9f2fae1e0 100644
--- a/mysql-test/r/order_by.result
+++ b/mysql-test/r/order_by.result
@@ -3159,3 +3159,51 @@ pk
 2
 3
 DROP TABLE t1;
+#
+# MDEV-13994: Bad join results with orderby_uses_equalities=on
+#
+CREATE TABLE books (
+id int(16) NOT NULL AUTO_INCREMENT,
+library_id int(16) NOT NULL DEFAULT 0,
+wings_id int(12) NOT NULL DEFAULT 0,
+scheduled_for_removal int(1) DEFAULT 0,
+PRIMARY KEY (id),
+KEY library_idx (library_id)
+) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
+INSERT INTO books VALUES (32625,8663,707,0),(32624,8663,505,1);
+CREATE TABLE wings (
+id int(11) NOT NULL AUTO_INCREMENT,
+department_id int(11) DEFAULT NULL,
+PRIMARY KEY (id)
+) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
+INSERT INTO wings VALUES (505,11745),(707,11768);
+SET @save_optimizer_switch=@@optimizer_switch;
+SET optimizer_switch='orderby_uses_equalities=off';
+SELECT wings.id as wing_id, wings.department_id FROM wings
+WHERE wings.id IN ( SELECT books.wings_id FROM books
+WHERE books.library_id = 8663 AND
+books.scheduled_for_removal=0 )
+ORDER BY wings.id;
+wing_id	department_id
+707	11768
+SET optimizer_switch='orderby_uses_equalities=on';
+SELECT wings.id as wing_id, wings.department_id FROM wings
+WHERE wings.id IN ( SELECT books.wings_id FROM books
+WHERE books.library_id = 8663 AND
+books.scheduled_for_removal=0 )
+ORDER BY wings.id;
+wing_id	department_id
+707	11768
+explain extended SELECT wings.id as wing_id, wings.department_id FROM wings
+WHERE wings.id IN ( SELECT books.wings_id FROM books
+WHERE books.library_id = 8663 AND
+books.scheduled_for_removal=0 )
+ORDER BY wings.id;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	1	100.00	Using temporary; Using filesort
+1	PRIMARY	wings	eq_ref	PRIMARY	PRIMARY	4	test.books.wings_id	1	100.00	
+2	MATERIALIZED	books	ref	library_idx	library_idx	4	const	1	100.00	Using where
+Warnings:
+Note	1003	select `test`.`wings`.`id` AS `wing_id`,`test`.`wings`.`department_id` AS `department_id` from `test`.`wings` semi join (`test`.`books`) where `test`.`books`.`library_id` = 8663 and `test`.`books`.`scheduled_for_removal` = 0 and `test`.`wings`.`id` = `test`.`books`.`wings_id` order by `test`.`wings`.`id`
+set optimizer_switch= @save_optimizer_switch;
+DROP TABLE books, wings;