Two sharding tables cross database join, error

[FlyingMao]

• dble version：
  5.6.29-dble-9.9.9.9-f2ee68f267caf5c53371cb68de2068998b363b72-20190128080033
• preconditions ：

use schema1
drop table if exists sharding_4_t1
drop table if exists schema2.sharding_4_t2
CREATE TABLE sharding_4_t1(`id` int(10) unsigned NOT NULL,`t_id` int(10) unsigned NOT NULL DEFAULT '0',`name` char(120) NOT NULL DEFAULT '',`pad` int(11) NOT NULL,PRIMARY KEY (`id`),KEY `k_1` (`t_id`))DEFAULT CHARSET=UTF8
CREATE TABLE schema2.sharding_4_t2(`id` int(10) unsigned NOT NULL,`o_id` int(10) unsigned NOT NULL DEFAULT '0',`name` char(120) NOT NULL DEFAULT '',`pad` int(11) NOT NULL,PRIMARY KEY (`id`),KEY `k_1` (`o_id`))DEFAULT CHARSET=UTF8
insert into sharding_4_t1 values(1,1,'test中id为1',1),(2,2,'test_2',2),(3,3,'test中id为3',4),(4,4,'$test$4',3),(5,5,'test...5',1),(6,6,'test6',6)
insert into schema2.sharding_4_t2 values(1,1,'order中id为1',1),(2,2,'test_2',2),(3,3,'order中id为3',3),(4,4,'$order$4',4),(5,5,'order...5',1)

• configs：

schema.xml

<schema name="schema1" sqlMaxLimit="100" dataNode="dn5">
		<table name="sharding_4_t1" dataNode="dn1,dn2,dn3,dn4" rule="hash-four" />
	</schema>
	<schema name="schema2" sqlMaxLimit="100">
		<table name="sharding_4_t2" dataNode="dn1,dn2,dn3,dn4" rule="hash-four" />
	</schema>

rule.xml

server.xml

• steps：
  step1.

select * from sharding_4_t1 natural right join schema2.sharding_4_t2;

• expect result：
  1.

mysql> select * from sharding_4_t1 natural right join schema2.sharding_4_t2;
+----+----------------+-----+------+------+
| id | name           | pad | o_id | t_id |
+----+----------------+-----+------+------+
|  1 | order中id为1   |   1 |    1 | NULL |
|  2 | test_2         |   2 |    2 |    2 |
|  3 | order中id为3   |   3 |    3 | NULL |
|  4 | $order$4       |   4 |    4 | NULL |
|  5 | order...5      |   1 |    5 | NULL |
+----+----------------+-----+------+------+
5 rows in set (0.00 sec)

• real result：
  1.

mysql> select * from sharding_4_t1 natural right join schema2.sharding_4_t2;
ERROR 1003 (HY000): Table 'db3.sharding_4_t2' doesn't exist

• supplements：
  1.explain result in dble

mysql> explain select * from sharding_4_t1 natural right join schema2.sharding_4_t2;
+-----------------+---------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| DATA_NODE       | TYPE          | SQL/REF                                                                                                                                                                                                                                                                                                                              |
+-----------------+---------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| dn5_0           | BASE SQL      | select `sharding_4_t2`.`id`,`sharding_4_t2`.`m_id`,`sharding_4_t2`.`name`,`sharding_4_t2`.`pad` from  `sharding_4_t2` left join  `sharding_4_t1` on sharding_4_t2.id = sharding_4_t1.id and sharding_4_t2.m_id = sharding_4_t1.m_id and sharding_4_t2.name = sharding_4_t1.name and sharding_4_t2.pad = sharding_4_t1.pad where 1=1  |
| merge_1         | MERGE         | dn5_0                                                                                                                                                                                                                                                                                                                                |
| shuffle_field_1 | SHUFFLE_FIELD | merge_1                                                                                                                                                                                                                                                                                                                              |
+-----------------+---------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
3 rows in set (0.01 sec)

for tester
in autotest: dble/sqls/sqls_mixed/select/join_shardings.sql(line:88)

/label ~BUG

[FlyingMao]

verified version： 5.6.29-dble-9.9.9.9-d395c5efe3733f839360964cf9482465e95c7236-20190227063450