Slow performance on MySQL 5.6 trigger - mysql

Question

I have a large table with 80 million rows and a trigger that updates two other tables, all of which are TokuDB. The server is running Percona 5.6
CREATE TABLE `main` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`ip_addr` varchar(50) NOT NULL DEFAULT '',
`username` varchar(255) NOT NULL DEFAULT ''.
PRIMARY KEY (`id`),
) ENGINE=TokuDB;
The trigger code is
if NEW.ip_addr <> "" THEN
-- get the current oldest date
-- set #maxdate := now();
set #maxdate := (select lastseen from uniq_ip where data = NEW.ip_addr);
INSERT INTO uniq_ip (`data`, `total`, `lastseen`)
VALUES (NEW.ip_addr, 1, NEW.timestamp, #subnet)
ON DUPLICATE KEY UPDATE total = total + 1, lastseen = latest_date(NEW.timestamp, #maxdate);
end if;
-- get all values in one go, its indexed some query comes from index.
if NEW.username <> "" THEN
-- get the current oldest date
set #maxdate := (select lastseen from uniq_username where data = NEW.username);
INSERT INTO uniq_username (`data`, `total`, `lastseen`)
VALUES (NEW.username, 1, NEW.timestamp)
ON DUPLICATE KEY UPDATE total = total + 1, lastseen = latest_date(NEW.timestamp, #maxdate);
end if;
and the uniq_username and uniq_ip are
CREATE TABLE `uniq_ip` (
`data` varchar(42) NOT NULL,
`total` mediumint(4) unsigned NOT NULL DEFAULT '0',
`lastseen` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
PRIMARY KEY (`data`),
KEY `idx_lastseen` (`data`,`lastseen`)
) ENGINE=TokuDB DEFAULT CHARSET=ascii;
CREATE TABLE `uniq_username` (
`data` varchar(255) CHARACTER SET latin1 NOT NULL,
`total` mediumint(4) unsigned NOT NULL DEFAULT '0',
`lastseen` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
PRIMARY KEY (`data`),
KEY `idx_data_time` (`data`,`lastseen`)
) ENGINE=TokuDB DEFAULT CHARSET=utf8;
The problem is that a bulk insert under load works perfectly on the username part of the trigger when calculating the timeseen value. However the first part of the function to do the same on the uniq_ip table drops insert rate from 800/s to 30/s when it processes
set #maxdate := (select lastseen from uniq_ip where data = NEW.ip_addr);
If you set to the get now(), its fast (but not the correct result). uniq_username and uniq_ip have the same structure and indexes and the trigger slows right down regardless of which you process first (username or ip) but its only the above statement that slows the trigger down.
The problem below if the uniq_ip table is either TokuDB or InnoDB and the default charset makes no difference, neither does the insert statement being active or commented out. Latest_date() is a tiny function that returns the most recent datetime
Any ideas or tips?
Thanks

Answer 1

main.ip_addr is a latin1 and uniq_ip.data was casting as utf. Changing uniq_ip.data to latin1 improved the insert rate from 50 inserts/sec to 1000 inserts/sec. I guess that latin1->utf8 cast is a cpu killer