MDEV-7474: Semi-Join's DuplicateWeedout strategy skipped ...

JOIN::cur_dups_producing_tables was not maintained correctly in
the cases of greedy optimization (search_depth < n_tables).

Moved it to POSITION structure where it will be maintained automatically.

Removed POSITION::prefix_dups_producing_tables since its value can now
be calculated.

1 files changed, 84 insertions, 0 deletions

diff --git a/mysql-test/r/subselect_sj2_mat.result b/mysql-test/r/subselect_sj2_mat.result
index 0ff366b0d7a..4e75aee24a2 100644
--- a/mysql-test/r/subselect_sj2_mat.result
+++ b/mysql-test/r/subselect_sj2_mat.result
@@ -1180,6 +1180,90 @@ id	nombre
 2	row 2
 3	row 3
 DROP TABLE t1, t2;
+#
+# MDEV-7474: Semi-Join's DuplicateWeedout strategy skipped for some values of optimizer_search_depth
+#
+CREATE TABLE t1 (
+t1id BIGINT(20) NOT NULL,
+code VARCHAR(20),
+PRIMARY KEY (t1id)
+) COLLATE='utf8mb4_bin' ENGINE=InnoDB;
+CREATE TABLE t2 (
+t2id BIGINT(20) NOT NULL,
+t1idref BIGINT(20) NOT NULL,
+code VARCHAR(20),
+PRIMARY KEY (t2id),
+INDEX FK_T2_T1Id (t1idref),
+CONSTRAINT FK_T2_T1Id FOREIGN KEY (t1idref) REFERENCES t1 (t1id)
+) COLLATE='utf8mb4_bin' ENGINE=InnoDB;
+CREATE TABLE t3 (
+t3idref BIGINT(20) NOT NULL,
+t2idref BIGINT(20) NOT NULL,
+sequencenumber INT(10) NOT NULL,
+PRIMARY KEY (t3idref, t2idref),
+INDEX FK_T3_T2Id (t2idref),
+CONSTRAINT FK_T3_T2Id FOREIGN KEY (t2idref) REFERENCES t2 (t2id)
+) COLLATE='utf8mb4_bin' ENGINE=InnoDB;
+INSERT INTO t1 (t1id) VALUES (100001),(100017),(100018),(100026),(100027),(100028),(100029),(100030),
+(100031),(100032),(100033),(100034),(100035),(100036),(100037),(100038),(100040),(100041),(100042),
+(100043),(100044),(100045),(100046),(100047);
+INSERT IGNORE INTO t2 (t2id, t1idref) SELECT t1id, t1id FROM t1;
+INSERT IGNORE INTO t1 VALUES (200001, 'a');
+INSERT IGNORE INTO t2 (t2id, t1idref) VALUES (200011, 200001),(200012, 200001),(200013, 200001);
+INSERT IGNORE INTO t3 VALUES (1, 200011, 1),  (1, 200012, 2), (1, 200013, 3);
+set @tmp7474= @@optimizer_search_depth;
+SET SESSION optimizer_search_depth = 1;
+SELECT SQL_NO_CACHE 
+T2_0_.t1idref,
+T2_0_.t2id
+FROM
+t2 T2_0_ 
+WHERE
+T2_0_.t1idref IN (
+SELECT
+T1_1_.t1id 
+FROM
+t3 T3_0_ 
+INNER JOIN
+t2 T2_1_ 
+ON T3_0_.t2idref=T2_1_.t2id 
+INNER JOIN
+t1 T1_1_ 
+ON T2_1_.t1idref=T1_1_.t1id            
+WHERE
+T3_0_.t3idref= 1
+);
+t1idref	t2id
+200001	200011
+200001	200012
+200001	200013
+explain SELECT SQL_NO_CACHE 
+T2_0_.t1idref,
+T2_0_.t2id
+FROM
+t2 T2_0_ 
+WHERE
+T2_0_.t1idref IN (
+SELECT
+T1_1_.t1id 
+FROM
+t3 T3_0_ 
+INNER JOIN
+t2 T2_1_ 
+ON T3_0_.t2idref=T2_1_.t2id 
+INNER JOIN
+t1 T1_1_ 
+ON T2_1_.t1idref=T1_1_.t1id            
+WHERE
+T3_0_.t3idref= 1
+);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	T3_0_	ref	PRIMARY,FK_T3_T2Id	PRIMARY	8	const	3	Using index; Start temporary
+1	PRIMARY	T2_1_	eq_ref	PRIMARY,FK_T2_T1Id	PRIMARY	8	test.T3_0_.t2idref	1	
+1	PRIMARY	T1_1_	eq_ref	PRIMARY	PRIMARY	8	test.T2_1_.t1idref	1	Using index
+1	PRIMARY	T2_0_	ref	FK_T2_T1Id	FK_T2_T1Id	8	test.T2_1_.t1idref	1	Using index; End temporary
+drop table t3,t2,t1;
+set optimizer_search_depth=@tmp7474;
 # This must be the last in the file:
 set optimizer_switch=@subselect_sj2_tmp;
 set optimizer_switch=default;