ALTER TABLE IMPORT enhancement for Partitioned tables

diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc

index 5b6cbd35e25..ba33526662f 100644

--- a/sql/ha_partition.cc

+++ b/sql/ha_partition.cc

@@ -740,6 +740,12 @@ int ha_partition::create_partitioning_metadata(const char *path,

 }

+int ha_partition::discard_or_import_tablespace(my_bool discard)

+{

+  if (m_innodb) return 0;

+  return handler::discard_or_import_tablespace(discard);

+}

+

 /*

   Create a partitioned table

diff --git a/sql/ha_partition.h b/sql/ha_partition.h

index d450f96f4f9..7676b1887bb 100644

--- a/sql/ha_partition.h

+++ b/sql/ha_partition.h

@@ -545,6 +545,7 @@ class ha_partition final :public handler

   */

   int delete_table(const char *from) override;

   int rename_table(const char *from, const char *to) override;

+  int discard_or_import_tablespace(my_bool discard) override;

   int create(const char *name, TABLE *form,

              HA_CREATE_INFO *create_info) override;

   int create_partitioning_metadata(const char *name,

MariaDB [import]> show tables;

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

| Tables_in_import |

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

| t1               |

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

1 row in set (0.004 sec)

MariaDB [import]> alter table t2 import tablespace;

Query OK, 0 rows affected (0.001 sec)

MariaDB [import]> select * from t2;

ERROR 1814 (HY000): Tablespace has been discarded for table `t2`

MariaDB [import]> show create table t2\G

*************************** 1. row ***************************

       Table: t2

Create Table: CREATE TABLE `t2` (

  `employee_id` int(11) DEFAULT NULL,

  `name` varchar(50) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci

 PARTITION BY RANGE (`employee_id`)

(PARTITION `p0` VALUES LESS THAN (6) ENGINE = InnoDB,

 PARTITION `p1` VALUES LESS THAN (11) ENGINE = InnoDB,

 PARTITION `p2` VALUES LESS THAN (16) ENGINE = InnoDB,

 PARTITION `p3` VALUES LESS THAN MAXVALUE ENGINE = InnoDB)

1 row in set (0.000 sec)