Row Constructor Expression selects not using index - mysql

Question

we have this table
CREATE TABLE `resource_grant` (
`resource_grant_id` int(11) NOT NULL AUTO_INCREMENT,
`member_type_id` int(11) NOT NULL,
`member_ref` varchar(36) NOT NULL,
`resource_type_id` int(11) NOT NULL,
`resource_ref` varchar(36) NOT NULL,
`role_id` int(11) NOT NULL,
`modified_by` varchar(255) NOT NULL,
`modified_timestamp` timestamp(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
`deleted` tinyint(1) NOT NULL DEFAULT '0',
`parent_grant_id` int(11) DEFAULT NULL,
PRIMARY KEY (`resource_grant_id`),
UNIQUE KEY `member_ref` (`member_ref`,`member_type_id`,`resource_type_id`,`resource_ref`),
KEY `member_type_id` (`member_type_id`),
KEY `resource_type_id` (`resource_type_id`),
KEY `role_id` (`role_id`),
KEY `resource_ref` (`resource_ref`,`resource_type_id`),
KEY `idx_rg_parent_grant_id` (`parent_grant_id`),
KEY `resource_ref_2` (`resource_ref`,`member_ref`,`resource_type_id`,`member_type_id`,`role_id`),
CONSTRAINT `resource_grant_ibfk_1` FOREIGN KEY (`member_type_id`) REFERENCES `member_type` (`member_type_id`),
CONSTRAINT `resource_grant_ibfk_2` FOREIGN KEY (`resource_type_id`) REFERENCES `resource_type` (`resource_type_id`),
CONSTRAINT `resource_grant_ibfk_3` FOREIGN KEY (`role_id`) REFERENCES `role` (`role_id`)
) ENGINE=InnoDB;
and these related tables
CREATE TABLE `member_type` (
`member_type_id` int(11) NOT NULL AUTO_INCREMENT,
`member_type` varchar(36) NOT NULL,
`modified_by` varchar(36) NOT NULL,
`modified_timestamp` timestamp(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
`deleted` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`member_type_id`),
UNIQUE KEY `member_type` (`member_type`),
KEY `member_type_2` (`member_type`)
) ENGINE=InnoDB;
CREATE TABLE `resource_type` (
`resource_type_id` int(11) NOT NULL AUTO_INCREMENT,
`resource_type` varchar(36) NOT NULL,
`modified_by` varchar(36) NOT NULL,
`modified_timestamp` timestamp(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
`deleted` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`resource_type_id`),
UNIQUE KEY `resource_type` (`resource_type`),
KEY `resource_type_2` (`resource_type`)
) ENGINE=InnoDB;
CREATE TABLE `role` (
`role_id` int(11) NOT NULL AUTO_INCREMENT,
`role_ref` varchar(50) NOT NULL,
`name` varchar(256) NOT NULL,
`modified_by` varchar(36) NOT NULL,
`modified_timestamp` timestamp(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
`deleted` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`role_id`),
UNIQUE KEY `role_ref` (`role_ref`),
KEY `role_ref_2` (`role_ref`)
) ENGINE=InnoDB;
and we need to run selects like these ("Row Constructor Expression" syntax) (basically "bulk selects")
SELECT rg.resource_grant_id
FROM resource_grant rg
JOIN resource_type rt ON rg.resource_type_id = rt.resource_type_id
JOIN member_type mt ON rg.member_type_id = mt.member_type_id
JOIN role r ON r.role_id = rg.role_id
WHERE
(rg.resource_ref, rg.member_ref, rt.resource_type, mt.member_type, r.role_ref)
IN
(
('759','624962','property','epc-user','role.171'),
('11974','624962','property','epc-user','role.171')
);
the selects take ~60s to run, which is unacceptably long
note that there IS an index for (resource_ref,member_ref,resource_type_id,member_type_id,role_id)
we also don't want to run n individual select statements - we need these "bulk selects".
mysql 5.6 docs talk about this style of select not using indexes but you can make it using some tricks
https://dev.mysql.com/doc/refman/5.6/en/row-constructor-optimization.html
https://dev.mysql.com/doc/refman/5.6/en/range-optimization.html
not sure what's missing for us in order to make it use the indexes
EDIT here's the plan
mysql> explain SELECT rg.resource_grant_id FROM resource_grant rg JOIN resource_type rt ON rg.resource_type_id = rt.resource_type_id JOIN member_type mt ON rg.member_type_id = mt.member_type_id JOIN role r ON r.role_id = rg.role_id WHERE (rg.resource_ref, rg.member_ref, rt.resource_type, mt.member_type, r.role_ref) IN ( ('759','624962','property','epc-user','role.171'), ('11974','624962','property','epc-user','role.171') );
+----+-------------+-------+--------+-----------------------------------------+----------------+---------+--------------------------+---------+----------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+-----------------------------------------+----------------+---------+--------------------------+---------+----------------------------------------------------+
| 1 | SIMPLE | rt | index | PRIMARY | resource_type | 38 | NULL | 3 | Using index |
| 1 | SIMPLE | mt | index | PRIMARY | member_type | 38 | NULL | 6 | Using index; Using join buffer (Block Nested Loop) |
| 1 | SIMPLE | rg | ref | member_type_id,resource_type_id,role_id | member_type_id | 4 | samsDB.mt.member_type_id | 2370237 | Using where |
| 1 | SIMPLE | r | eq_ref | PRIMARY | PRIMARY | 4 | samsDB.rg.role_id | 1 | Using where |
+----+-------------+-------+--------+-----------------------------------------+----------------+---------+--------------------------+---------+----------------------------------------------------+
4 rows in set (0.53 sec)

Answer 1

Start by changing the where clause to:
WHERE rg.member_ref = '624962' AND
rt.resource_type = 'property' AND
mt.member_type = 'epc-user' AND
r.role_ref = 'role.171' AND
rg.resource_ref IN ('759', '11974')
The existing indexes are not quite optimal for this. You need an index where the first two keys are (member_ref, resource_ref) -- well, except in the most recent versions of MySQL which implement skip-scan index optimizations.
You might be able to change resource_ref_2 to:
KEY `resource_ref_2` (`member_ref`, `resource_ref`, `resource_type_id`, `member_type_id`, `role_id`),

Answer 2

I'm not surprised at 60s on 5.6. "Row constructors" have existed for a long time. But they were not optimized before 5.7.
Either upgrade or rewrite the WHERE as Gordon suggests.