Optimize a joined MySQL query - mysql

Question

There is this query that have been bugging me in two days now, it used to work good but now it slows down the entire cluster environment, the query is as seen below:
SELECT userUploads.*,
users_avatar.avatar AS avatar
FROM userUploads
LEFT JOIN users_avatar
ON userUploads.udid = users_avatar.udid
INNER JOIN user_subscription
ON (
user_subscription.sub_1 = 'G:123456789'
AND user_subscription.sub_2 = userUploads.udid
)
WHERE userUploads.platform = 'Private'
AND userUploads.STATUS IN ( 'featured', 'approved' )
ORDER BY userUploads.id DESC
LIMIT 50 OFFSET 0
I would really appreciate if anyone can help out with this query.
Below is the explain of the query:
+----+-------------+-------------------+--------+----------------------+----------+---------+------------------------+------+-----------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------------+--------+----------------------+----------+---------+------------------------+------+-----------------------------+
| 1 | SIMPLE | userUploads | range | platform,udid,status | platform | 154 | NULL | 12 | Using where; Using filesort |
| 1 | SIMPLE | users_avatar | eq_ref | PRIMARY | PRIMARY | 182 | Seeds.userUploads.udid | 1 | |
| 1 | SIMPLE | user_subscription | ref | sub_1,sub_2 | sub_1 | 93 | const | 7 | Using where |
+----+-------------+-------------------+--------+----------------------+----------+---------+------------------------+------+-----------------------------+
Thanks in advance
EDIT** show create table can seen below
Below is the show create table for the tables hope you have any ideas dancrumb.
| users_avatar | CREATE TABLE `users_avatar` (
`udid` varchar(60) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
`avatar` varchar(448) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`udid`)
) ENGINE=ndbcluster DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci |
| userUploads | CREATE TABLE `userUploads` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`bdaha` varchar(100) COLLATE utf8_unicode_ci DEFAULT NULL,
`user` varchar(60) COLLATE utf8_unicode_ci DEFAULT NULL,
`direktoren` text COLLATE utf8_unicode_ci,
`filnamnet` varchar(180) COLLATE utf8_unicode_ci DEFAULT NULL,
`karhes` varchar(150) COLLATE utf8_unicode_ci DEFAULT NULL,
`version` char(10) COLLATE utf8_unicode_ci DEFAULT NULL,
`rostat` int(10) DEFAULT NULL,
`stars` int(11) DEFAULT NULL,
`statyn` varchar(20) COLLATE utf8_unicode_ci DEFAULT NULL,
`platform` char(30) COLLATE utf8_unicode_ci DEFAULT NULL,
`images` int(2) DEFAULT NULL,
`date` char(10) COLLATE utf8_unicode_ci DEFAULT NULL,
`udid` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL,
`favorirepris` int(8) DEFAULT NULL,
`hikes` char(4) COLLATE utf8_unicode_ci DEFAULT 'no',
`dbn` char(6) COLLATE utf8_unicode_ci DEFAULT NULL,
`timestamp` char(20) COLLATE utf8_unicode_ci DEFAULT NULL,
`comments` int(5) DEFAULT NULL,
`klistret` enum('no','yes') COLLATE utf8_unicode_ci NOT NULL DEFAULT 'no',
PRIMARY KEY (`id`),
KEY `platform` (`platform`,`status`),
KEY `udid` (`udid`),
KEY `hikes` (`hikes`),
KEY `bdaha` (`bdaha`),
KEY `statyn` (`statyn`),
KEY `version` (`version`)
) ENGINE=ndbcluster AUTO_INCREMENT=118831 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci |
| user_subscription | CREATE TABLE `user_subscription` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`sub_1` varchar(30) COLLATE utf8_unicode_ci DEFAULT NULL,
`sub_2` varchar(30) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `sub_1` (`sub_1`),
KEY `sub_2` (`sub_2`)
) ENGINE=ndbcluster AUTO_INCREMENT=155184 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci |

Answer 1

Well, you have a filesort on userUploads which is always slow. You may want to play with indices to remove that. For example, you may want to start with an index on udid, platform, and status.

Answer 2

In general when querying you want to perform the most limiting operations in terms of data returned first so that other operations are only performed on the data that is actually in the results.
In this case try reordering the inner join to user_subscription and the left join to users_avatar. This way it will only attempt to even get the avatar for a user if they are actually in the result set rather than it looking up all the avatars first then filtering based on joins and where clauses.
SELECT userUploads.*,
users_avatar.avatar AS avatar
FROM userUploads
INNER JOIN user_subscription
ON (
user_subscription.sub_1 = 'G:123456789'
AND user_subscription.sub_2 = userUploads.udid
)
LEFT JOIN users_avatar
ON userUploads.udid = users_avatar.udid
WHERE userUploads.platform = 'Private'
AND userUploads.STATUS IN ( 'featured', 'approved' )
ORDER BY userUploads.id DESC
LIMIT 50 OFFSET 0