Triple thread hang in states 'NULL', 'NULL' and 'closing tables' on INSERT

INSTALL PLUGIN Spider SONAME 'ha_spider.so';

CREATE USER Spider@localhost IDENTIFIED BY '';

CREATE SERVER srv FOREIGN DATA WRAPPER MYSQL OPTIONS (SOCKET '../socket.sock',DATABASE 'test',user 'Spider',PASSWORD '');

CREATE TABLE t (c1 INT) ENGINE=Spider COMMENT='WRAPPER "mysql",srv "srv",TABLE "t"';

SELECT CONCAT ('FROM JSON subSELECT ',c,' AS CHAR(1))'),CAST((SELECT 1 FROM t) AS CHAR(1)) FROM t WHERE c='NULL';

CREATE TABLE t1 (c1 INT) ENGINE=Spider COMMENT='WRAPPER "mysql",srv "srv",TABLE "t"';

INSERT INTO t1 VALUES (0);

10.11.1-dbg>SHOW PROCESSLIST;

+----+-------------+-----------+------+---------+------+----------------------------------------------------+----------------------------------------+----------+

| Id | User        | Host      | db   | Command | Time | State                                              | Info                                   | Progress |

+----+-------------+-----------+------+---------+------+----------------------------------------------------+----------------------------------------+----------+

|  4 | root        | localhost | test | Query   |  100 | closing tables                                     | INSERT INTO t1 VALUES (0)              |    0.000 |

|  5 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

|  6 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

|  7 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

|  8 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

|  9 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 10 | system user |           | NULL | Sleep   |  100 | Reset for next command                             | NULL                                   |    0.000 |

| 11 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 12 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 13 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 14 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 15 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 16 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 17 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 19 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 20 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 18 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 21 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 22 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 23 | system user |           | NULL | Daemon  | NULL | Spider table background cardinality action handler | NULL                                   |    0.000 |

| 24 | system user |           | NULL | Daemon  | NULL | Spider table background statistics action handler  | NULL                                   |    0.000 |

| 26 | Spider      | localhost | test | Query   |  100 | NULL                                               | show table status from `test` like 't' |    0.000 |

| 27 | Spider      | localhost | test | Query   |  100 | NULL                                               | show table status from `test` like 't' |    0.000 |

| 28 | root        | localhost | test | Query   |    0 | starting                                           | SHOW PROCESSLIST                       |    0.000 |

+----+-------------+-----------+------+---------+------+----------------------------------------------------+----------------------------------------+----------+

24 rows in set (0.000 sec)