Question

I’m trying to populate some data for a table. The query is being run on a table that contains ~50 million records. The query I’m currently using is below. It counts the number of rows that match the template id and are BETWEEN two unix timestamps:

SELECT COUNT(*) as count FROM `s_log` 
WHERE `time_sent` BETWEEN '1346904000' AND '1346993271' 
AND `template` = '1'

While the query above does work, performance is rather slow while looping through each template which at times can be in the hundreds. The time stamps are stored as int and are properly indexed. Just to test thing out, I tried running the query below, omitting the time_sent restriction:

SELECT COUNT(*) as count FROM `s_log` 
AND `template` = '1'

As expected, it runs very fast, but is obviously not restricting count results inside the correct time frame. How can I obtain a count for a specific template AND restrict that count BETWEEN two unix timestamps?

EXPLAIN:

1 | SIMPLE | s_log | ref | time_sent,template | template | 4 | const | 71925 | Using where

SHOW CREATE TABLE s_log:

CREATE TABLE `s_log` (
 `id` int(255) NOT NULL AUTO_INCREMENT,
 `email` varchar(255) NOT NULL,
 `time_sent` int(25) NOT NULL,
 `template` int(55) NOT NULL,
 `key` varchar(255) NOT NULL,
 `node_id` int(55) NOT NULL,
 `status` varchar(55) NOT NULL,
 PRIMARY KEY (`id`),
 KEY `email` (`email`),
 KEY `time_sent` (`time_sent`),
 KEY `template` (`template`),
 KEY `node_id` (`node_id`),
 KEY `key` (`key`),
 KEY `status` (`status`),
 KEY `timestamp` (`timestamp`)
) ENGINE=MyISAM AUTO_INCREMENT=2078966 DEFAULT CHARSET=latin1

Answer 1

The best index you may have in this case is composite one template + time_sent

CREATE INDEX template_time_sent ON s_log (template, time_sent)

PS: Also as long as all your columns in the query are integer DON’T enclose their values in quotes (in some cases it could lead to issues, at least with older mysql versions)