MariaDB [federated]> show analyze for 5;
+------+--------------------+------------+--------+---------------+---------+---------+------+------+--------+----------+------------+------------------------------------------------+
| id   | select_type        | table      | type   | possible_keys | key     | key_len | ref  | rows | r_rows | filtered | r_filtered | Extra                                          |
+------+--------------------+------------+--------+---------------+---------+---------+------+------+--------+----------+------------+------------------------------------------------+
|    1 | PRIMARY            | OUTR2      | index  | PRIMARY       | k_int   | 5       | NULL |  100 | 68.00  |   100.00 |     100.00 | Using index                                    |
|    1 | PRIMARY            | OUTR3      | ALL    | k_int         | NULL    | NULL    | NULL |  100 | 76.49  |   100.00 |     100.00 | Range checked for each record (index map: 0x4) |
|    1 | PRIMARY            | OUTR1      | ALL    | NULL          | NULL    | NULL    | NULL |  100 | 99.98  |   100.00 |       1.32 | Using where                                    |
|    2 | DEPENDENT SUBQUERY | INNR1      | eq_ref | PRIMARY       | PRIMARY | 4       | func |    1 | 1.00   |   100.00 |      14.43 | Using where                                    |
|    3 | DEPENDENT UNION    | INNR1      | index  | NULL          | u_int   | 5       | NULL |  100 | 100.00 |   100.00 |     100.00 | Using index                                    |
| NULL | UNION RESULT       | <union2,3> | ALL    | NULL          | NULL    | NULL    | NULL | NULL | 0.29   |     NULL |       NULL |                                                |
+------+--------------------+------------+--------+---------------+---------+---------+------+------+--------+----------+------------+------------------------------------------------+