MDEV-4161 Assertion `status_var.memory_used == 0' fails in virtual THD::~THD()

init join->top_join_tab_count to be in sync with join->join_tab=stat,
otherwise a query can be killed in-between and join_tab's won't be deleted
(JOIN::cleanup won't call JOIN_TAB::cleanup)

mysql-test/r/quick_select_4161.result

+CREATE TABLE t1 (
+event_date date DEFAULT '0000-00-00' NOT NULL,
+type int(11) DEFAULT '0' NOT NULL,
+event_id int(11) DEFAULT '0' NOT NULL,
+PRIMARY KEY (event_date,type,event_id)
+);
+INSERT INTO t1 VALUES ('1999-07-10',100100,24), ('1999-07-11',100100,25),
+('1999-07-13',100600,0), ('1999-07-13',100600,4), ('1999-07-13',100600,26),
+('1999-07-14',100600,10), ('1999-07-15',100600,16), ('1999-07-15',100800,45),
+('1999-07-15',101000,47), ('1999-07-16',100800,46), ('1999-07-20',100600,5),
+('1999-07-20',100600,27), ('1999-07-21',100600,11), ('1999-07-22',100600,17),
+('1999-07-23',100100,39), ('1999-07-24',100100,39), ('1999-07-24',100500,40),
+('1999-07-25',100100,39), ('1999-07-27',100600,1), ('1999-07-27',100600,6),
+('1999-07-27',100600,28), ('1999-07-28',100600,12), ('1999-07-29',100500,41),
+('1999-07-29',100600,18), ('1999-07-30',100500,41), ('1999-07-31',100500,41),
+('1999-08-01',100700,34), ('1999-08-03',100600,7), ('1999-08-03',100600,29),
+('1999-08-04',100600,13), ('1999-08-05',100500,42), ('1999-08-05',100600,19),
+('1999-08-06',100500,42), ('1999-08-07',100500,42), ('1999-08-08',100500,42),
+('1999-08-10',100600,2), ('1999-08-10',100600,9), ('1999-08-10',100600,30),
+('1999-08-11',100600,14), ('1999-08-12',100600,20), ('1999-08-17',100500,8),
+('1999-08-17',100600,31), ('1999-08-18',100600,15), ('1999-08-19',100600,22),
+('1999-08-24',100600,3), ('1999-08-24',100600,32), ('1999-08-27',100500,43),
+('1999-08-31',100600,33), ('1999-09-17',100100,37), ('1999-09-18',100100,37),
+('1999-09-19',100100,37), ('2000-12-18',100700,38);
+set debug_sync='inside_make_join_statistics signal killme wait_for done';
+select event_date,type,event_id from t1 WHERE event_date >= "1999-07-01" AND event_date < "1999-07-15" AND (type=100600 OR type=100100) ORDER BY event_date;
+set debug_sync='now wait_for killme';
+kill %connection%;
+set debug_sync='now signal done';
+Got one of the listed errors
+drop table t1;

mysql-test/r/windows.result

@@ -16,7 +16,7 @@ CREATE TABLE t1 (a int, b int);
 INSERT INTO t1 VALUES (1,1);
 EXPLAIN SELECT * FROM t1 WHERE b =  (SELECT max(2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 DROP TABLE t1;
 CREATE DATABASE `TESTDB`;

mysql-test/t/quick_select_4161.test

+#
+# MDEV-4161 Assertion `status_var.memory_used == 0' fails in virtual THD::~THD()
+#
+--source include/have_debug_sync.inc
+
+CREATE TABLE t1 (
+  event_date date DEFAULT '0000-00-00' NOT NULL,
+  type int(11) DEFAULT '0' NOT NULL,
+  event_id int(11) DEFAULT '0' NOT NULL,
+  PRIMARY KEY (event_date,type,event_id)
+);
+
+INSERT INTO t1 VALUES ('1999-07-10',100100,24), ('1999-07-11',100100,25),
+('1999-07-13',100600,0), ('1999-07-13',100600,4), ('1999-07-13',100600,26),
+('1999-07-14',100600,10), ('1999-07-15',100600,16), ('1999-07-15',100800,45),
+('1999-07-15',101000,47), ('1999-07-16',100800,46), ('1999-07-20',100600,5),
+('1999-07-20',100600,27), ('1999-07-21',100600,11), ('1999-07-22',100600,17),
+('1999-07-23',100100,39), ('1999-07-24',100100,39), ('1999-07-24',100500,40),
+('1999-07-25',100100,39), ('1999-07-27',100600,1), ('1999-07-27',100600,6),
+('1999-07-27',100600,28), ('1999-07-28',100600,12), ('1999-07-29',100500,41),
+('1999-07-29',100600,18), ('1999-07-30',100500,41), ('1999-07-31',100500,41),
+('1999-08-01',100700,34), ('1999-08-03',100600,7), ('1999-08-03',100600,29),
+('1999-08-04',100600,13), ('1999-08-05',100500,42), ('1999-08-05',100600,19),
+('1999-08-06',100500,42), ('1999-08-07',100500,42), ('1999-08-08',100500,42),
+('1999-08-10',100600,2), ('1999-08-10',100600,9), ('1999-08-10',100600,30),
+('1999-08-11',100600,14), ('1999-08-12',100600,20), ('1999-08-17',100500,8),
+('1999-08-17',100600,31), ('1999-08-18',100600,15), ('1999-08-19',100600,22),
+('1999-08-24',100600,3), ('1999-08-24',100600,32), ('1999-08-27',100500,43),
+('1999-08-31',100600,33), ('1999-09-17',100100,37), ('1999-09-18',100100,37),
+('1999-09-19',100100,37), ('2000-12-18',100700,38);
+
+connect (killee, localhost, root);
+
+let $id=`select connection_id()`;
+
+set debug_sync='inside_make_join_statistics signal killme wait_for done';
+send select event_date,type,event_id from t1 WHERE event_date >= "1999-07-01" AND event_date < "1999-07-15" AND (type=100600 OR type=100100) ORDER BY event_date;
+
+connection default;
+set debug_sync='now wait_for killme';
+--replace_result $id %connection%
+eval kill $id;
+set debug_sync='now signal done';
+
+connection killee;
+--error 1053,1927,2006,2013
+reap;
+
+connection default;
+disconnect killee;
+
+drop table t1;
+

sql/sql_select.cc

@@ -3682,6 +3682,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
     DBUG_RETURN(TRUE);
 
   join->join_tab=stat;
+  join->top_join_tab_count= table_count;
   join->map2table=stat_ref;
   join->table= table_vector;
   join->const_tables=const_count;
@@ -3729,6 +3730,8 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list,
   if (join->choose_subquery_plan(all_table_map & ~join->const_table_map))
     goto error;
 
+  DEBUG_SYNC(join->thd, "inside_make_join_statistics");
+
   /* Generate an execution plan from the found optimal join order. */
   DBUG_RETURN(join->thd->killed || get_best_combination(join));