diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result
index 74049298981..434b3b46351 100644
--- a/mysql-test/r/subselect.result
+++ b/mysql-test/r/subselect.result
@@ -4975,3 +4975,39 @@ k
 3
 drop table t1,t2,t3;
 drop view v2;
+#
+# Bug#52068: Optimizer generates invalid semijoin materialization plan
+#
+drop table if exists ot1, ot2, it1, it2;
+CREATE TABLE ot1(a INTEGER);
+INSERT INTO ot1 VALUES(5), (8);
+CREATE TABLE it2(a INTEGER);
+INSERT INTO it2 VALUES(9), (5), (1), (8);
+CREATE TABLE it3(a INTEGER);
+INSERT INTO it3 VALUES(7), (1), (0), (5), (1), (4);
+CREATE TABLE ot4(a INTEGER);
+INSERT INTO ot4 VALUES(1), (3), (5), (7), (9), (7), (3), (1);
+SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+a	a
+5	1
+8	1
+5	5
+8	5
+5	7
+8	7
+5	7
+8	7
+5	1
+8	1
+explain SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	24	
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
+2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+DROP TABLE IF EXISTS ot1, ot4, it2, it3;
diff --git a/mysql-test/r/subselect_no_mat.result b/mysql-test/r/subselect_no_mat.result
index 46e99151fb7..563762eedde 100644
--- a/mysql-test/r/subselect_no_mat.result
+++ b/mysql-test/r/subselect_no_mat.result
@@ -4978,6 +4978,41 @@ k
 3
 drop table t1,t2,t3;
 drop view v2;
+#
+# Bug#52068: Optimizer generates invalid semijoin materialization plan
+#
+drop table if exists ot1, ot2, it1, it2;
+CREATE TABLE ot1(a INTEGER);
+INSERT INTO ot1 VALUES(5), (8);
+CREATE TABLE it2(a INTEGER);
+INSERT INTO it2 VALUES(9), (5), (1), (8);
+CREATE TABLE it3(a INTEGER);
+INSERT INTO it3 VALUES(7), (1), (0), (5), (1), (4);
+CREATE TABLE ot4(a INTEGER);
+INSERT INTO ot4 VALUES(1), (3), (5), (7), (9), (7), (3), (1);
+SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+a	a
+5	1
+8	1
+5	5
+8	5
+5	7
+8	7
+5	7
+8	7
+5	1
+8	1
+explain SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
+1	PRIMARY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (flat, BNL join)
+DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 set optimizer_switch=default;
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
diff --git a/mysql-test/r/subselect_no_opts.result b/mysql-test/r/subselect_no_opts.result
index d697e2dbbc8..ee2e58b3e0c 100644
--- a/mysql-test/r/subselect_no_opts.result
+++ b/mysql-test/r/subselect_no_opts.result
@@ -4975,4 +4975,39 @@ k
 3
 drop table t1,t2,t3;
 drop view v2;
+#
+# Bug#52068: Optimizer generates invalid semijoin materialization plan
+#
+drop table if exists ot1, ot2, it1, it2;
+CREATE TABLE ot1(a INTEGER);
+INSERT INTO ot1 VALUES(5), (8);
+CREATE TABLE it2(a INTEGER);
+INSERT INTO it2 VALUES(9), (5), (1), (8);
+CREATE TABLE it3(a INTEGER);
+INSERT INTO it3 VALUES(7), (1), (0), (5), (1), (4);
+CREATE TABLE ot4(a INTEGER);
+INSERT INTO ot4 VALUES(1), (3), (5), (7), (9), (7), (3), (1);
+SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+a	a
+5	1
+8	1
+5	5
+8	5
+5	7
+8	7
+5	7
+8	7
+5	1
+8	1
+explain SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	DEPENDENT SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer (flat, BNL join)
+DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 set optimizer_switch=default;
diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result
index 1eae8184dfd..07655f837a3 100644
--- a/mysql-test/r/subselect_no_semijoin.result
+++ b/mysql-test/r/subselect_no_semijoin.result
@@ -4975,4 +4975,39 @@ k
 3
 drop table t1,t2,t3;
 drop view v2;
+#
+# Bug#52068: Optimizer generates invalid semijoin materialization plan
+#
+drop table if exists ot1, ot2, it1, it2;
+CREATE TABLE ot1(a INTEGER);
+INSERT INTO ot1 VALUES(5), (8);
+CREATE TABLE it2(a INTEGER);
+INSERT INTO it2 VALUES(9), (5), (1), (8);
+CREATE TABLE it3(a INTEGER);
+INSERT INTO it3 VALUES(7), (1), (0), (5), (1), (4);
+CREATE TABLE ot4(a INTEGER);
+INSERT INTO ot4 VALUES(1), (3), (5), (7), (9), (7), (3), (1);
+SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+a	a
+5	1
+8	1
+5	5
+8	5
+5	7
+8	7
+5	7
+8	7
+5	1
+8	1
+explain SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+FROM it2,it3);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
+2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
+DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 set optimizer_switch=default;
diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test
index d1ca98962d6..047987da3f7 100644
--- a/mysql-test/t/subselect.test
+++ b/mysql-test/t/subselect.test
@@ -4251,3 +4251,30 @@ select * from t3 where k in (select j from v2);
 
 drop table t1,t2,t3;
 drop view v2;
+
+--echo #
+--echo # Bug#52068: Optimizer generates invalid semijoin materialization plan
+--echo #
+--disable_warnings
+drop table if exists ot1, ot2, it1, it2;
+--enable_warnings
+CREATE TABLE ot1(a INTEGER);
+INSERT INTO ot1 VALUES(5), (8);
+CREATE TABLE it2(a INTEGER);
+INSERT INTO it2 VALUES(9), (5), (1), (8);
+CREATE TABLE it3(a INTEGER);
+INSERT INTO it3 VALUES(7), (1), (0), (5), (1), (4);
+CREATE TABLE ot4(a INTEGER);
+INSERT INTO ot4 VALUES(1), (3), (5), (7), (9), (7), (3), (1);
+
+let $query=
+SELECT * FROM ot1,ot4
+WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
+                        FROM it2,it3);
+
+eval $query;
+eval explain $query;
+
+DROP TABLE IF EXISTS ot1, ot4, it2, it3;
+
+
diff --git a/sql/sql_join_cache.cc b/sql/sql_join_cache.cc
index 2c28aae781c..501ec0faf23 100644
--- a/sql/sql_join_cache.cc
+++ b/sql/sql_join_cache.cc
@@ -169,9 +169,17 @@ JOIN_TAB *JOIN_CACHE::get_next_table(JOIN_TAB *tab)
   if (join_tab->first_sjm_sibling)
     return tab;
   uint i= tab-join->join_tab;
+  /*
+  Temporary measure before MWL#90 refactorings are there: if 'tab' is at upper
+  level (i.e. it's not inside an SJM nest), still include into the join buffer
+  the tables from within SJM nest.  We might need the subquery's select list
+  columns, because SJ-Materialization-Scan upacks data to those. 
+
   while (sj_is_materialize_strategy(join->best_positions[i].sj_strategy) &&
          i < join->tables)
     i+= join->best_positions[i].n_sj_tables;
+
+  */
   return join->join_tab+i < join_tab ? join->join_tab+i : NULL; 
 }
 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 16fbb309d89..b3078bd3d47 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13168,6 +13168,15 @@ sub_select_sjm(JOIN *join, JOIN_TAB *join_tab, bool end_of_records)
       last_tab->read_record.read_record= rr_sequential_and_unpack;
     }
   }
+  else
+  {
+    if (sjm->is_sj_scan)
+    {
+      /* Reset the cursor for a new scan over the table */
+      if (sjm->table->file->ha_rnd_init(TRUE))
+        DBUG_RETURN(NESTED_LOOP_ERROR);
+    }
+  }
 
   if (sjm->is_sj_scan)
   {