How can i optimize this mysql query in social table structure? - mysql

Question

Scheme
CREATE TABLE IF NOT EXISTS `content` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`entity_uid` int(11) NOT NULL,
....
PRIMARY KEY (`uid`),
UNIQUE KEY `insert_at` (`insert_at`),
KEY `fk_entity` (`entity_uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `entity` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `entity_comment` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`entity_uid` int(11) NOT NULL,
`user_uid` int(11) NOT NULL,
....
PRIMARY KEY (`uid`),
KEY `fk_entity` (`entity_uid`),
KEY `fk_user` (`user_uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `entity_like` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`entity_uid` int(11) NOT NULL,
`user_uid` int(11) NOT NULL,
....
PRIMARY KEY (`uid`),
KEY `fk_entity` (`entity_uid`),
KEY `fk_user` (`user_uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `entity_share` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`entity_uid` int(11) NOT NULL,
`user_uid` int(11) NOT NULL,
`share_type` int(2) NOT NULL,
....
PRIMARY KEY (`uid`),
KEY `fk_entity` (`entity_uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `entity_view` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`entity_uid` int(11) NOT NULL,
`user_uid` int(11) NOT NULL,
....
PRIMARY KEY (`uid`),
KEY `fk_entity` (`entity_uid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `user` (
`uid` int(11) NOT NULL AUTO_INCREMENT,
`email` varchar(30) NOT NULL,
....
PRIMARY KEY (`uid`),
UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query 1 - using Left Join [Query took 16.3032 sec]
SELECT c . * , COUNT(DISTINCT ev.uid) AS view_count, COUNT( DISTINCT el.uid ) AS like_count, COUNT( DISTINCT ec.uid ) AS reply_count, COUNT( DISTINCT es.uid ) AS share_count
FROM content AS c
LEFT JOIN entity_view AS ev ON ev.entity_uid = c.entity_uid
LEFT JOIN entity_like AS el ON el.entity_uid = c.entity_uid
LEFT JOIN entity_share AS es ON es.entity_uid = c.entity_uid
LEFT JOIN entity_comment AS ec ON ec.entity_uid = c.entity_uid
GROUP BY c.uid
EDIT - Explain
Query 2 - using Sub query [Query took 0.0069 sec]
SELECT c.*,
(SELECT COUNT(*) FROM entity_view WHERE entity_uid = c.entity_uid) AS view_count ,
(SELECT COUNT(*) FROM entity_like WHERE entity_uid = c.entity_uid) AS like_count ,
(SELECT COUNT(*) FROM entity_comment WHERE entity_uid = c.entity_uid) AS reply_count ,
(SELECT COUNT(*) FROM entity_share WHERE entity_uid = c.entity_uid) AS share_count
FROM content AS c
EDIT - Explain
Result
uid | data of content | view_count | like_count | reply_count | share_count |
-----------------------------------------------------------------------------
1 | ..... | 100 | 10 | 5 | 6 |
-----------------------------------------------------------------------------
2 | ..... | 200 | 20 | 20 | 3 |
-----------------------------------------------------------------------------
3 | ..... | 300 | 10 | 10 | 2 |
-----------------------------------------------------------------------------
Explain
Storage Engine : InnoDB
entity_{action} : Insert occurs when user {action} occurs.(e.g) entity_view is insertion occurs when user sees the content.
Question
How can I optimize more in the above mysql query?
I run the query in two ways and got the results above.
This proved that subquery is much better.
Is there a way to a get better performance than subquery like this table structure? And why is left join so bad?