Trouble with subquery but only in view - mysql

Question

I have some trouble with the following query:
DROP VIEW IF EXISTS own_inst_stakes_detail_all;
CREATE VIEW `own_inst_stakes_detail_all` AS
SELECT
`own_inst_stakes_detail`.`FactSet_Entity_ID` AS `factset_entity_id`,
`own_inst_stakes_detail`.`FSYM_ID` AS `fsym_id`,
`own_inst_stakes_detail`.`as_of_date` AS `report_date`,
`own_inst_stakes_detail`.`Position` AS `adj_holding`,
`own_inst_stakes_detail`.`Position` / (SELECT own_sec_prices.adj_shares_outstanding FROM own_sec_prices WHERE own_sec_prices.`FSYM_ID` = own_inst_stakes_detail.`FSYM_ID` ORDER BY ABS(DATEDIFF(own_sec_prices.price_date, `own_inst_stakes_detail`.`as_of_date`)) DESC LIMIT 1) AS `adj_ratio`,
`own_inst_stakes_detail`.`Position` AS `reported_holding`,
`sym_coverage`.`Proper_Name` AS `security_proper_name`,
`sym_entity`.`Entity_Proper_Name` AS `entity_proper_name`
FROM
`own_inst_stakes_detail`
LEFT JOIN `sym_entity` ON `sym_entity`.`FactSet_Entity_ID` = `own_inst_stakes_detail`.`FactSet_Entity_ID`
LEFT JOIN `sym_coverage` ON `sym_coverage`.`FSYM_ID` = `own_inst_stakes_detail`.`FSYM_ID`;
It uses the following tables, which are of particular interest:
CREATE TABLE `own_inst_stakes_detail` (
`FactSet_Entity_ID` CHAR(8) NOT NULL,
`FSYM_ID` CHAR(8) NOT NULL,
`as_of_date` DATE NOT NULL,
`Position` DOUBLE DEFAULT NULL,
PRIMARY KEY (`FactSet_Entity_ID`,`FSYM_ID`,`as_of_date`),
KEY `idx_own_inst_stakes_detail_FactSet_Entity_ID` (`FactSet_Entity_ID`),
KEY `idx_own_inst_stakes_detail_FSYM_ID` (`FSYM_ID`),
KEY `idx_own_inst_stakes_detail_as_of_date` (`as_of_date`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
CREATE TABLE `own_sec_prices` (
`FSYM_ID` CHAR(8) NOT NULL,
`price_date` DATE NOT NULL,
`unadj_shares_outstanding` DOUBLE NOT NULL,
`adj_shares_outstanding` DOUBLE NOT NULL,
PRIMARY KEY (`FSYM_ID`,`price_date`),
KEY `idx_own_sec_prices_FSYM_ID` (`FSYM_ID`),
KEY `idx_own_sec_prices_price_date` (`price_date`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
The query in the view works really well running just the query but it is a catastrophe if that is wrapped in a view. The query never completes, probably because of a full table scan. The tables are really big which I am using here.
I have tried that with MySQL Server 5.7 (btw., with MariaDB 10.1 there are no problems). Is there a way to improve that?
The EXPLAINs look as follows (Maria and My):
MariaDB [factset]> explain SELECT * FROM own_inst_stakes_detail_all WHERE FSYM_ID = 'WK13LJ-S' ORDER BY report_date DESC, adj_ratio DESC;
+------+--------------------+------------------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+--------------------+------------------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------------------------------------------------+
| 1 | PRIMARY | own_inst_stakes_detail | ref | idx_own_inst_stakes_detail_FSYM_ID | idx_own_inst_stakes_detail_FSYM_ID | 8 | const | 8 | Using index condition; Using where; Using filesort |
| 1 | PRIMARY | sym_entity | eq_ref | PRIMARY | PRIMARY | 8 | factset.own_inst_stakes_detail.FactSet_Entity_ID | 1 | |
| 1 | PRIMARY | sym_coverage | const | PRIMARY | PRIMARY | 8 | const | 1 | Using where |
| 3 | DEPENDENT SUBQUERY | own_sec_prices | ref | PRIMARY,idx_own_sec_prices_FSYM_ID | idx_own_sec_prices_FSYM_ID | 8 | factset.own_inst_stakes_detail.FSYM_ID | 10 | Using temporary; Using filesort |
+------+--------------------+------------------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------------------------------------------------+
4 rows in set (0.01 sec)
mysql> explain SELECT * FROM own_inst_stakes_detail_all WHERE FSYM_ID = 'WK13LJ-S' ORDER BY report_date DESC, adj_ratio DESC;
+----+--------------------+------------------------+------------+--------+------------------------------------+----------------------------+---------+--------------------------------------------------+--------+----------+---------------------------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+--------------------+------------------------+------------+--------+------------------------------------+----------------------------+---------+--------------------------------------------------+--------+----------+---------------------------------+
| 1 | PRIMARY | <derived2> | NULL | ref | <auto_key0> | <auto_key0> | 8 | const | 10 | 100.00 | Using where; Using filesort |
| 2 | DERIVED | own_inst_stakes_detail | NULL | ALL | NULL | NULL | NULL | NULL | 817961 | 100.00 | NULL |
| 2 | DERIVED | sym_entity | NULL | eq_ref | PRIMARY | PRIMARY | 8 | factset.own_inst_stakes_detail.FactSet_Entity_ID | 1 | 100.00 | NULL |
| 2 | DERIVED | sym_coverage | NULL | eq_ref | PRIMARY | PRIMARY | 8 | factset.own_inst_stakes_detail.FSYM_ID | 1 | 100.00 | NULL |
| 3 | DEPENDENT SUBQUERY | own_sec_prices | NULL | ref | PRIMARY,idx_own_sec_prices_FSYM_ID | idx_own_sec_prices_FSYM_ID | 8 | factset.own_inst_stakes_detail.FSYM_ID | 10 | 100.00 | Using temporary; Using filesort |
+----+--------------------+------------------------+------------+--------+------------------------------------+----------------------------+---------+--------------------------------------------------+--------+----------+---------------------------------+
5 rows in set, 3 warnings (0.08 sec)
To me it looks like MySQL cannot use the index idx_own_inst_stakes_detail_FSYM_ID. But if I change the column with the subquery to "1 as adj_ratio", the following happens:
mysql> explain SELECT * FROM own_inst_stakes_detail_all WHERE FSYM_ID = 'WK13LJ-S';
+----+-------------+------------------------+------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------+-------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+------------------------+------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------+-------+
| 1 | SIMPLE | own_inst_stakes_detail | NULL | ref | idx_own_inst_stakes_detail_FSYM_ID | idx_own_inst_stakes_detail_FSYM_ID | 8 | const | 8 | 100.00 | NULL |
| 1 | SIMPLE | sym_entity | NULL | eq_ref | PRIMARY | PRIMARY | 8 | factset.own_inst_stakes_detail.FactSet_Entity_ID | 1 | 100.00 | NULL |
| 1 | SIMPLE | sym_coverage | NULL | const | PRIMARY | PRIMARY | 8 | const | 1 | 100.00 | NULL |
+----+-------------+------------------------+------------+--------+------------------------------------+------------------------------------+---------+--------------------------------------------------+------+----------+-------+
3 rows in set, 1 warning (0.00 sec)
That works well! Any help is greatly appreciated. Thanks!