MySQL Slow ORDER BY when done on JOIN value? - mysql

Question

I have this query:
SELECT
c.*,
cv.views
FROM
content AS c
JOIN
content_views AS cv ON cv.content = c.record_num
WHERE
c.enabled = 1
ORDER BY
cv.views
Quite simple, but it's really slow... Is there a way to make it faster ?
This is my EXPLAIN:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE c ref enabled_2,enabled enabled 4 const 23947 Using temporary; Using filesort
1 SIMPLE cv eq_ref PRIMARY PRIMARY 4 c.record_num 1
EDIT 2016-02-24
Please note that usually, I use a LIMIT so the number of records returned in the EXPLAIN isn't entirely accurate, however for the sake of simplicity and because the performance doesn't change with the LIMIT or without it, I have removed it.
As requested in the comments, this is the result of my SHOW CREATE TABLE. As you can see, one of my table is MyISAM while the other is InnoDB.
CREATE TABLE `content` (
`title` varchar(255) NOT NULL DEFAULT '',
`filename` varchar(255) NOT NULL DEFAULT '',
`filename_2` varchar(255) NOT NULL,
`filename_3` varchar(255) NOT NULL,
`orig_filename` varchar(255) NOT NULL,
`trailer_filename` varchar(255) NOT NULL,
`thumbnail` varchar(255) NOT NULL DEFAULT '',
`embed` text NOT NULL,
`description` text NOT NULL,
`paysite` int(11) NOT NULL DEFAULT '0',
`keywords` varchar(255) NOT NULL,
`model` varchar(255) NOT NULL DEFAULT '',
`scheduled_date` date NOT NULL DEFAULT '0000-00-00',
`date_added` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`encoded_date` datetime NOT NULL,
`rating` int(5) NOT NULL DEFAULT '0',
`length` int(11) NOT NULL DEFAULT '0',
`submitter` int(11) NOT NULL DEFAULT '0',
`ip` varchar(15) NOT NULL,
`approved` int(11) NOT NULL DEFAULT '0',
`hotlinked` varchar(1024) NOT NULL,
`plug_url` varchar(255) NOT NULL,
`enabled` int(11) NOT NULL DEFAULT '0',
`main_thumb` int(11) NOT NULL DEFAULT '3',
`xml` varchar(32) NOT NULL,
`photos` int(11) NOT NULL DEFAULT '0',
`mobile` varchar(255) NOT NULL,
`modeltmp` varchar(255) NOT NULL,
`movie_width` int(11) NOT NULL,
`movie_height` int(11) NOT NULL,
`token` varchar(255) DEFAULT NULL,
`source_thumb_url` varchar(255) NOT NULL,
`related` varchar(1024) NOT NULL,
`force_related` varchar(255) NOT NULL,
`record_num` int(11) NOT NULL AUTO_INCREMENT,
`webvtt_src` text NOT NULL,
`category_thumb` int(11) NOT NULL,
`related_date` date NOT NULL,
`publish_ready` tinyint(1) NOT NULL,
PRIMARY KEY (`record_num`),
KEY `encoded_date` (`encoded_date`,`photos`,`enabled`),
KEY `filename` (`filename`),
KEY `scheduled_date` (`scheduled_date`),
KEY `enabled_2` (`enabled`,`length`,`photos`),
KEY `enabled` (`enabled`,`encoded_date`,`photos`),
KEY `rating` (`rating`,`enabled`,`photos`),
KEY `token` (`token`),
KEY `submitter` (`submitter`),
FULLTEXT KEY `keywords` (`keywords`,`title`),
FULLTEXT KEY `title` (`title`),
FULLTEXT KEY `description` (`description`),
FULLTEXT KEY `keywords_2` (`keywords`)
) ENGINE=MyISAM AUTO_INCREMENT=124207 DEFAULT CHARSET=latin1
CREATE TABLE `content_views` (
`views` int(11) NOT NULL,
`content` int(11) NOT NULL,
PRIMARY KEY (`content`),
KEY `views` (`views`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1

Answer 1

For this query:
SELECT c.*, cv.views
FROM content c JOIN
content_views cv
ON cv.content = c.record_num
WHERE c.enabled = 1
ORDER BY cv.views;
The best indexes are probably content(enabled, record_num) and content_views(content, views). I am guessing that the performance even with these indexes will be similar to what you have now.