Mysql – EAV, multiple left join query optimisation

eavMySQLmysql-5.5

Any assitance would be greatly welcomed. Pardon my ignorance however I am wondering if anyone else has had to encounter bad EAV performance issues. I have a particular query which takes a long time. What is the best way to increase the speed on this?

 SELECT * FROM
(
    SELECT f.*, p.`timestamp`
    FROM `tObjectValues` ov
    INNER JOIN `tObjectProperties` op ON ov.`propertyId` = op.`id`
    INNER JOIN `tObjects` o ON op.`objectId` = o.`id`
    INNER JOIN `files` f ON SUBSTRING(ov.`value`, CHAR_LENGTH('cache://content//')) = f.`filename`
    LEFT JOIN `publishFiles` pf ON f.`id` = pf.`fileId`
    LEFT JOIN `publishes` p ON p.`id` = pf.`publishId` AND o.`appId` = p.`appId` AND p.`type` = 'l'
    WHERE o.`status` = 1 AND op.`status` = 1 AND ov.`status` = 1 AND ov.`value` LIKE 'cache://content/%' AND o.`appId` = 2
    ORDER BY p.`timestamp` DESC
    LIMIT 0, 10000000
) s
GROUP BY s.`id`

I have run the explain function to delve further into the issue however i was wondering if anyone who has had similar problem could help in the optimisation.

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Best Answer

  • Please explain the order by - limit - group by. It sounds kludgy and possibly illegal in future versions.
  • Store the tail of the filename so you can avoid SUBSTRING (etc) in critical places like WHERE clauses.
  • Show us SHOW CREATE TABLE.
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