MDEV-30540 Wrong result with IN list length reaching IN_PREDICATE_CON…

…VERSION_THRESHOLD

The problem was the mysql_derived_prepare() did not correctly set
'distinct' when creating a temporary derivated table.

Fixed by separating checking for distinct for queries with and without
UNION.

Other things:
- Fixed bug in generate_derived_keys_for_table() where we set the wrong
  bit for join_tab->keys
- Cleaned up JOIN::drop_unused_derived_keys()
- Changed TABLE::use_index() to keep unique keys and update
  share->key_parts

Author: Sergei Petrunia <sergey@mariadb.com>, monty@mariadb.org

mysql-test/main/derived.result

@@ -1315,7 +1315,7 @@ a	a
 analyze select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except(select t3.a from t3 order by b))q  where t1.a=q.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	Using where
-1	PRIMARY	<derived2>	ref	key0	key0	5	test.t1.a	1	0.50	100.00	100.00	
+1	PRIMARY	<derived2>	eq_ref	distinct_key	distinct_key	5	test.t1.a	1	0.50	100.00	100.00	
 2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
 3	UNION	t2	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
 4	EXCEPT	t3	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
@@ -1325,6 +1325,23 @@ a	a
 3	3
 4	4
 6	6
+analyze select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except ALL (select t3.a from t3 order by b))q  where t1.a=q.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	r_rows	filtered	r_filtered	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	Using where
+1	PRIMARY	<derived2>	ref	key0	key0	5	test.t1.a	1	1.17	100.00	100.00	
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
+3	UNION	t2	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
+4	EXCEPT	t3	ALL	NULL	NULL	NULL	NULL	6	6.00	100.00	100.00	
+NULL	UNIT RESULT	<unit2,3,4>	ALL	NULL	NULL	NULL	NULL	NULL	7.00	NULL	NULL	
+select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except ALL (select t3.a from t3 order by b))q  where t1.a=q.a;
+a	a
+3	3
+3	3
+4	4
+4	4
+5	5
+6	6
+6	6
 drop table t1,t2,t3;
 #
 # MDEV-16549: Server crashes in Item_field::fix_fields on query with
@@ -1438,5 +1455,26 @@ SET @@IN_PREDICATE_CONVERSION_THRESHOLD=@@global.IN_PREDICATE_CONVERSION_THRESHO
 SET @@OPTIMIZER_SWITCH=@@global.OPTIMIZER_SWITCH;
 DROP TABLE t1, t2;
 #
+# MDEV-30540 Wrong result with IN list length reaching
+# IN_PREDICATE_CONVERSION_THRESHOLD
+#
+CREATE TABLE t1 (a INT PRIMARY KEY);
+INSERT INTO t1 SELECT seq FROM seq_1_to_30;
+ANALYZE TABLE t1 PERSISTENT FOR ALL;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+SET IN_PREDICATE_CONVERSION_THRESHOLD=4;
+SELECT a FROM t1 WHERE a IN ( 1, 1, 2, 194 );
+a
+1
+2
+SET IN_PREDICATE_CONVERSION_THRESHOLD=100;
+SELECT a FROM t1 WHERE a IN ( 1, 1, 2, 194 );
+a
+1
+2
+drop table t1;
+#
 # End of 11.0 tests
 #

mysql-test/main/derived.test

@@ -1130,6 +1130,11 @@ analyze select * from t1 , ( (select t2.a from t2 order by c) union all (select
 
 select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except(select t3.a from t3 order by b))q  where t1.a=q.a;
 
+analyze select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except ALL (select t3.a from t3 order by b))q  where t1.a=q.a;
+
+select * from t1 , ( (select t2.a from t2 order by c) union all (select  t2.a from t2 order by c) except ALL (select t3.a from t3 order by b))q  where t1.a=q.a;
+
+
 drop table t1,t2,t3;
 
 --echo #
@@ -1224,6 +1229,20 @@ SET @@IN_PREDICATE_CONVERSION_THRESHOLD=@@global.IN_PREDICATE_CONVERSION_THRESHO
 SET @@OPTIMIZER_SWITCH=@@global.OPTIMIZER_SWITCH;
 DROP TABLE t1, t2;
 
+--echo #
+--echo # MDEV-30540 Wrong result with IN list length reaching
+--echo # IN_PREDICATE_CONVERSION_THRESHOLD
+--echo #
+
+CREATE TABLE t1 (a INT PRIMARY KEY);
+INSERT INTO t1 SELECT seq FROM seq_1_to_30;
+ANALYZE TABLE t1 PERSISTENT FOR ALL;
+SET IN_PREDICATE_CONVERSION_THRESHOLD=4;
+SELECT a FROM t1 WHERE a IN ( 1, 1, 2, 194 );
+SET IN_PREDICATE_CONVERSION_THRESHOLD=100;
+SELECT a FROM t1 WHERE a IN ( 1, 1, 2, 194 );
+drop table t1;
+
 --echo #
 --echo # End of 11.0 tests
 --echo #