Extremely slow query- Using google sql cloud - mysql

Question

Is there a way I can speed this up? Right now it's taking an unbelievably insane amount of time to query.
SELECT trades.*, trader1.user_name as trader1_name,
trader2.user_name as trader2_name FROM trades
LEFT JOIN logs_players trader1 ON trader1.user_id = trader1_account_id
LEFT JOIN logs_players trader2 ON trader2.user_id = trader2_account_id
ORDER BY time_added
LIMIT 20 OFFSET 0;
I've done as much as I could in terms of searching online for a solution. Or even just trying to get some more information why it's taking so long to execute.
The query takes about 45 seconds or so to complete.
Create statements:
CREATE TABLE `trades` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`trader1_account_id` int(11) DEFAULT NULL,
`trader2_account_id` int(11) DEFAULT NULL,
`trader1_value` bigint(20) DEFAULT NULL,
`trader2_value` bigint(20) DEFAULT NULL,
`trader1_ip` varchar(16) DEFAULT NULL,
`trader2_ip` varchar(16) DEFAULT NULL,
`world` int(11) DEFAULT NULL,
`x` int(11) DEFAULT NULL,
`z` int(11) DEFAULT NULL,
`level` int(11) DEFAULT NULL,
`trader1_user` varchar(12) DEFAULT NULL,
`trader2_user` varchar(12) DEFAULT NULL,
`time_added` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8
CREATE TABLE `logs_players` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) DEFAULT NULL,
`user_name` varchar(20) DEFAULT NULL,
`world_stage` varchar(20) DEFAULT NULL,
`world_type` varchar(20) DEFAULT NULL,
`bank` longtext,
`inventory` longtext,
`equipment` longtext,
`total_wealth` mediumtext,
`total_play_time` mediumtext,
`rights` int(11) DEFAULT NULL,
`icon` int(11) DEFAULT NULL,
`ironmode` int(11) DEFAULT NULL,
`x` int(11) DEFAULT NULL,
`z` int(11) DEFAULT NULL,
`level` int(11) DEFAULT NULL,
`last_ip` varchar(16) DEFAULT NULL,
`last_online` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`muted_until` timestamp NULL DEFAULT NULL,
`banned_until` timestamp NULL DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8

Answer 1

I filled a sample database with 10k rows each, and found that a few indexes were what you needed:
ALTER TABLE `logs_players` ADD INDEX(`user_id`);
ALTER TABLE `trades` ADD INDEX(`time_added`);
The main index we need is an index on user_id. Changing that we went from a query time of 20.1390 seconds, to 0.0130 seconds:
We can even get that down further, by adding an index on time_added to make sorting a lot faster, now we ended up with an impressive query time:
Do some research on indexes! A simple EXPLAIN query would show you that you're using filesort (Which is rather bad!):
After indexes, this looks a lot better: