Improve SQL Query perofrmance - mysql

Question

I have a complex query which takes 700ms to run on my machine. I found that the bottleneck is the ORDER BY at_firstname.value clause, but how can I use indexes to improve this?
SELECT
`e`.*
, `at_default_billing`.`value` AS `default_billing`
, `at_billing_postcode`.`value` AS `billing_postcode`
, `at_billing_city`.`value` AS `billing_city`
, `at_billing_region`.`value` AS `billing_region`
, `at_billing_country_id`.`value` AS `billing_country_id`
, `at_company`.`value` AS `company`
, `at_firstname`.`value` AS `firstname`
, `at_lastname`.`value` AS `lastname`
, CONCAT(at_firstname.value
, " "
, at_lastname.value) AS `full_name`
, `at_phone`.`value` AS `phone`
, IFNULL(at_phone.value,"N/A") AS `telephone`
, `e`.`entity_id` AS `id`
FROM
`customer_entity` AS `e`
LEFT JOIN
`customer_entity_int` AS `at_default_billing`
ON (`at_default_billing`.`entity_id` = `e`.`entity_id`)
AND (`at_default_billing`.`attribute_id` = '13')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_postcode`
ON (`at_billing_postcode`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_postcode`.`attribute_id` = '30')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_city`
ON (`at_billing_city`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_city`.`attribute_id` = '26')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_region`
ON (`at_billing_region`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_region`.`attribute_id` = '28')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_country_id`
ON (`at_billing_country_id`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_country_id`.`attribute_id` = '27')
LEFT JOIN
`customer_address_entity_varchar` AS `at_company`
ON (`at_company`.`entity_id` = `at_default_billing`.`value`)
AND (`at_company`.`attribute_id` = '24')
LEFT JOIN
`customer_entity_varchar` AS `at_firstname`
ON (`at_firstname`.`entity_id` = `e`.`entity_id`)
AND (`at_firstname`.`attribute_id` = '5')
LEFT JOIN
`customer_entity_varchar` AS `at_lastname`
ON (`at_lastname`.`entity_id` = `e`.`entity_id`)
AND (`at_lastname`.`attribute_id` = '7')
LEFT JOIN
`customer_entity_varchar` AS `at_phone`
ON (`at_phone`.`entity_id` = `e`.`entity_id`)
AND (`at_phone`.`attribute_id` = '136')
ORDER BY
`at_firstname`.`value` ASC LIMIT 20
This is execution plan :
EXPLAIN of Query :
'1','SIMPLE','e',NULL,'ALL',NULL,NULL,NULL,NULL,'19951','100.00','Using temporary; Using filesort'
'1','SIMPLE','at_default_billing',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_INT_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_INT_ENTITY_ID,IDX_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_INT_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_billing_postcode',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_city',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_region',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_billing_country_id',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_company',NULL,'eq_ref','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ADDRESS_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.at_default_billing.value,const','1','100.00','Using where'
'1','SIMPLE','at_firstname',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_lastname',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
'1','SIMPLE','at_phone',NULL,'eq_ref','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID,IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE','UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID','6','lazurd.e.entity_id,const','1','100.00',NULL
Table Structure:
CREATE TABLE `customer_entity_varchar` (
`value_id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'Value Id',
`entity_type_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Entity Type Id',
`attribute_id` smallint(5) unsigned NOT NULL DEFAULT '0' COMMENT 'Attribute Id',
`entity_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'Entity Id',
`value` varchar(255) DEFAULT NULL COMMENT 'Value',
PRIMARY KEY (`value_id`),
UNIQUE KEY `UNQ_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID` (`entity_id`,`attribute_id`),
KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_TYPE_ID` (`entity_type_id`),
KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ATTRIBUTE_ID` (`attribute_id`),
KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID` (`entity_id`),
KEY `IDX_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_ATTRIBUTE_ID_VALUE` (`entity_id`,`attribute_id`,`value`),
CONSTRAINT `FK_CSTR_ENTT_VCHR_ATTR_ID_EAV_ATTR_ATTR_ID` FOREIGN KEY (`attribute_id`) REFERENCES `eav_attribute` (`attribute_id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `FK_CSTR_ENTT_VCHR_ENTT_TYPE_ID_EAV_ENTT_TYPE_ENTT_TYPE_ID` FOREIGN KEY (`entity_type_id`) REFERENCES `eav_entity_type` (`entity_type_id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `FK_CUSTOMER_ENTITY_VARCHAR_ENTITY_ID_CUSTOMER_ENTITY_ENTITY_ID` FOREIGN KEY (`entity_id`) REFERENCES `customer_entity` (`entity_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=131094 DEFAULT CHARSET=utf8 COMMENT='Customer Entity Varchar';

Answer 1

As of now your query is:
Performing ALL left outer joins first.
Then ORDERing the rows.
Then LIMITing the rows.
I would perform the strictly needed outer joins first, then ordering and limiting (to reduce to 20 rows), and finally I would do all the rest of the outer joins. In short I would do:
Performing minimal left outer join first. That is, two tables only.
Then ORDERing the rows.
Then LIMITing the rows. This produce a max of 20 rows.
Perform all the rest of outer joins. At this point this is not thousands of rows anymore, but only 20.
This change should massively reduce the "Unique Key Lookup" executions. The modified query will look like:
select
e.*
, `at_default_billing`.`value` AS `default_billing`
, `at_billing_postcode`.`value` AS `billing_postcode`
, `at_billing_city`.`value` AS `billing_city`
, `at_billing_region`.`value` AS `billing_region`
, `at_billing_country_id`.`value` AS `billing_country_id`
, `at_company`.`value` AS `company`
, `at_lastname`.`value` AS `lastname`
, CONCAT(firstname
, " "
, at_lastname.value) AS `full_name`
, `at_phone`.`value` AS `phone`
, IFNULL(at_phone.value,"N/A") AS `telephone`
from ( -- Step #1: joining customer_entity with customer_entity_varchar
SELECT
`e`.*
, `at_firstname`.`value` AS `firstname`
, `e`.`entity_id` AS `id`
FROM
`customer_entity` AS `e`
LEFT JOIN
`customer_entity_varchar` AS `at_firstname`
ON (`at_firstname`.`entity_id` = `e`.`entity_id`)
AND (`at_firstname`.`attribute_id` = '5')
ORDER BY -- Step #2: Sorting (the bare minimum)
`at_firstname`.`value` ASC
LIMIT 20 -- Step #3: Limiting (to 20 rows)
) e
LEFT JOIN -- Step #4: Performing all the rest of outer joins (only few rows now)
`customer_entity_int` AS `at_default_billing`
ON (`at_default_billing`.`entity_id` = `e`.`entity_id`)
AND (`at_default_billing`.`attribute_id` = '13')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_postcode`
ON (`at_billing_postcode`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_postcode`.`attribute_id` = '30')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_city`
ON (`at_billing_city`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_city`.`attribute_id` = '26')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_region`
ON (`at_billing_region`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_region`.`attribute_id` = '28')
LEFT JOIN
`customer_address_entity_varchar` AS `at_billing_country_id`
ON (`at_billing_country_id`.`entity_id` = `at_default_billing`.`value`)
AND (`at_billing_country_id`.`attribute_id` = '27')
LEFT JOIN
`customer_address_entity_varchar` AS `at_company`
ON (`at_company`.`entity_id` = `at_default_billing`.`value`)
AND (`at_company`.`attribute_id` = '24')
LEFT JOIN
`customer_entity_varchar` AS `at_lastname`
ON (`at_lastname`.`entity_id` = `e`.`entity_id`)
AND (`at_lastname`.`attribute_id` = '7')
LEFT JOIN
`customer_entity_varchar` AS `at_phone`
ON (`at_phone`.`entity_id` = `e`.`entity_id`)
AND (`at_phone`.`attribute_id` = '136')

Answer 2

Unfortunately, SELECT whole_mess_of_rows FROM many_tables ORDER BY one_col LIMIT small_number is a notorious performance antipattern. Why? Because it sorts a big result set, just to discard most of it.
The trick is to cheaply find out which rows are within that LIMIT small_number, then retrieve only those rows from the larger query.
Which rows do you want? It looks to me like this query will retrieve their customer_entity.id values. But it's hard to be sure, so you should test this subquery.
SELECT customer_entity.entity_id
FROM customer_entity
LEFT JOIN customer_entity_varchar AS at_firstname
ON (at_firstname.entity_id = e.entity_id)
AND (at_firstname.attribute_id = '5')
ORDER BY at_firstname.value ASC
LIMIT 20
This should give the twenty relevant entity_id values. Test it. Look at its execution plan. Add an appropriate index to customer_entity if need be. That index might be (firstname_attribute_id, firstname_entity_id, firstname_value) But I am guessing.
Then you can put this at the end of your main query, right before ORDER BY.
WHERE e.entity_id IN (
SELECT customer_entity.entity_id
FROM customer_entity
LEFT JOIN customer_entity_varchar AS at_firstname
ON (at_firstname.entity_id = e.entity_id)
AND (at_firstname.attribute_id = '5')
ORDER BY at_firstname.value ASC
LIMIT 20
)
and things should be a bit faster.

Answer 3

I agree with the previous Answers, but want to emphasize on more antipattern: Over-noramlization.
Your schema is a curious (and inefficient) variant on the already-bad EAV schema pattern.
There is little advantage, and some disadvantage in splitting customer_address_entity_varchar across 5 tables. Similarly for customer_entity_varchar.
An address should (usually) be stored as a few columns in a single table; no JOINs to other tables.
Likewise for firstname+lastname.
Phone could be another issue, since a person/company/entity could have multiple phone numbers (cell, home, work, fax, etc). But that is a different story.