MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in

Roll back to most general duplicate removing strategi in case of different stratagies for one position.

mysql-test/r/subselect.result

@@ -7146,3 +7146,29 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 (SELECT MAX(sq.f2) FROM t1)
 NULL
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests

mysql-test/r/subselect_no_mat.result

@@ -7143,6 +7143,32 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 (SELECT MAX(sq.f2) FROM t1)
 NULL
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 set optimizer_switch=default;
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'

mysql-test/r/subselect_no_opts.result

@@ -7141,4 +7141,30 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 (SELECT MAX(sq.f2) FROM t1)
 NULL
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 set @optimizer_switch_for_subselect_test=null;

mysql-test/r/subselect_no_scache.result

@@ -7152,6 +7152,32 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 (SELECT MAX(sq.f2) FROM t1)
 NULL
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 set optimizer_switch=default;
 select @@optimizer_switch like '%subquery_cache=on%';
 @@optimizer_switch like '%subquery_cache=on%'

mysql-test/r/subselect_no_semijoin.result

@@ -7141,5 +7141,31 @@ SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 (SELECT MAX(sq.f2) FROM t1)
 NULL
 drop table t1, t2;
+#
+# MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+# (5.5 test)
+#
+SET @optimiser_switch_save= @@optimizer_switch;
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+a
+5
+5
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+End of 5.5 tests
 set @optimizer_switch_for_subselect_test=null;
 set @join_cache_level_for_subselect_test=NULL;

mysql-test/t/subselect.test

@@ -6033,3 +6033,31 @@ CREATE TABLE t2 (f2 INT, KEY(f2)) ENGINE=MyISAM;
 INSERT t2 VALUES (6),(9);
 SELECT (SELECT MAX(sq.f2) FROM t1) FROM (SELECT * FROM t2) AS sq WHERE f2 = 2;
 drop table t1, t2;
+
+--echo #
+--echo # MDEV-13933: Wrong results in COUNT() query with EXISTS and exists_to_in
+--echo # (5.5 test)
+--echo #
+SET @optimiser_switch_save= @@optimizer_switch;
+ 
+CREATE TABLE t1 (a INT NOT NULL);
+INSERT INTO t1 VALUES (1),(1),(1),(5),(5);
+ 
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (5),(1);
+ 
+CREATE TABLE t3 (c INT, KEY(c));
+INSERT INTO t3 VALUES (5),(5);
+ 
+SET optimizer_switch='semijoin=on';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+ 
+SET optimizer_switch='semijoin=off';
+select t1.a from t1 where t1.a in (select `test`.`t2`.`b` from `test`.`t2`)
+and t1.a in (select `test`.`t3`.`c` from `test`.`t3`);
+ 
+SET @@optimizer_switch= @optimiser_switch_save;
+DROP TABLE t1, t2, t3;
+
+--echo End of 5.5 tests

sql/opt_subselect.cc

@@ -2687,7 +2687,8 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
     LooseScan detector in best_access_path)
   */
   remaining_tables &= ~new_join_tab->table->map;
-  table_map dups_producing_tables;
+  table_map dups_producing_tables, prev_dups_producing_tables,
+            prev_sjm_lookup_tables;
 
   if (idx == join->const_tables)
     dups_producing_tables= 0;
@@ -2698,7 +2699,7 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
   if ((emb_sj_nest= new_join_tab->emb_sj_nest))
     dups_producing_tables |= emb_sj_nest->sj_inner_tables;
 
-  Semi_join_strategy_picker **strategy;
+  Semi_join_strategy_picker **strategy, **prev_strategy;
   if (idx == join->const_tables)
   {
     /* First table, initialize pickers */
@@ -2753,6 +2754,22 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
             (read_time < *current_read_time &&
              !(handled_fanout & pos->inner_tables_handled_with_other_sjs)))
         {
+          DBUG_ASSERT(pos->sj_strategy != sj_strategy);
+          /*
+            If the strategy choosen first time or
+            the strategy replace strategy which was used to exectly the same
+            tables
+          */
+          if (pos->sj_strategy == SJ_OPT_NONE ||
+              handled_fanout ==
+                (prev_dups_producing_tables ^ dups_producing_tables))
+          {
+            prev_strategy= strategy;
+            if (pos->sj_strategy == SJ_OPT_NONE)
+            {
+              prev_dups_producing_tables= dups_producing_tables;
+              prev_sjm_lookup_tables= join->sjm_lookup_tables;
+            }
             /* Mark strategy as used */
             (*strategy)->mark_used();
             pos->sj_strategy= sj_strategy;
@@ -2765,10 +2782,25 @@ void advance_sj_state(JOIN *join, table_map remaining_tables, uint idx,
             dups_producing_tables &= ~handled_fanout;
             //TODO: update bitmap of semi-joins that were handled together with
             // others.
-          if (is_multiple_semi_joins(join, join->positions, idx, handled_fanout))
+            if (is_multiple_semi_joins(join, join->positions, idx,
+                                       handled_fanout))
               pos->inner_tables_handled_with_other_sjs |= handled_fanout;
           }
           else
+          {
+            /* Conflict fall to most general variant */
+            (*prev_strategy)->set_empty();
+            dups_producing_tables= prev_dups_producing_tables;
+            join->sjm_lookup_tables= prev_sjm_lookup_tables;
+            // mark it 'none' to avpoid loops
+            pos->sj_strategy= SJ_OPT_NONE;
+            // next skip to last;
+            strategy= pickers +
+              (sizeof(pickers)/sizeof(Semi_join_strategy_picker*) - 3);
+            continue;
+          }
+        }
+        else
         {
           /* We decided not to apply the strategy. */
           (*strategy)->set_empty();