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这是我第一次尝试在 StackOverflow 上寻求帮助 :)

我有下表：

CREATE TABLE `tinfinite_visits` (
  `visit_id` int(255) NOT NULL AUTO_INCREMENT,
  `identity_id` int(255) NOT NULL,
  `ip` varchar(39) NOT NULL,
  `loggedin` enum('0','1') NOT NULL DEFAULT '0',
  `url` longtext NOT NULL,
  `realurl` longtext NOT NULL,
  `referrer` longtext NOT NULL,
  `method` enum('GET','POST','HEAD','OPTIONS','PUT','DELETE','TRACE','CONNECT','PATCH') NOT NULL,
  `client` longtext NOT NULL,
  `referring` longtext NOT NULL,
  `timestart` datetime NOT NULL,
  `timeend` datetime NOT NULL,
  PRIMARY KEY (`visit_id`),
  KEY `timestart` (`timestart`),
  KEY `identity_id` (`identity_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8;

在某些时候，我需要从该表中获取一些数据来生成折线图。我目前使用 5 个不同的查询，针对 5 个不同的时间间隔（总计、年、月、周、日）进行此操作。

该表目前有大约 200.000 行，但会变得更大（甚至数千万条记录）。

虽然我的查询非常适合此目的，但我正在尝试找到一种更好的性能方式。

因此，我将非常感谢有关如何提高查询性能的任何提示/建议，如果可能的话，最好甚至将所有 5 个查询合并为 1 个。

我目前正在使用的查询、它们的解释以及它们的执行时间（大约 200.000 行）如下：

日查询：

SELECT COUNT(DISTINCT(`identity_id`)) AS visits, DATE_FORMAT(CONVERT_TZ(timestart, '-5:00', '+3:00'), '%l%p') AS unit
  FROM tinfinite_visits
  WHERE `timestart` >= DATE_SUB(NOW(), INTERVAL 24 HOUR)
  GROUP BY unit
  ORDER BY `timestart` ASC

解释：

+----+-------------+----------------------+-------+---------------+-----------+---------+-----+-------+------------------------------+
| id | select_type | table                | type  | possible_keys | key       | key_len | ref | rows  | Extra                        |
+----+-------------+----------------------+-------+---------------+-----------+---------+-----+-------+------------------------------+
| 1  | SIMPLE      | tinfinite_visits     | range | timestart     | timestart | 8       |     | 11113 | Using where; Using temporary |
+----+-------------+----------------------+-------+---------------+-----------+---------+-----+-------+------------------------------+

时间：0.011280059814453

周查询：

SELECT COUNT(DISTINCT(`identity_id`)) AS visits, DATE_FORMAT(CONVERT_TZ(timestart, '-5:00', '+3:00'), '%a') AS unit
  FROM tinfinite_visits
  WHERE `timestart` >= DATE_SUB(NOW(), INTERVAL 7 DAY)
  GROUP BY unit
  ORDER BY `timestart` ASC

解释：

+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| id | select_type | table            | type | possible_keys | key | key_len | ref | rows   | Extra                                        |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| 1  | SIMPLE      | tinfinite_visits | ALL  | timestart     |     |         |     | 205897 | Using where; Using temporary; Using filesort |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+

时间：0.13543295860291

月份查询：

SELECT COUNT(DISTINCT(`identity_id`)) AS visits, DATE_FORMAT(CONVERT_TZ(timestart, '-5:00', '+3:00'), '%d') AS unit
  FROM tinfinite_visits
  WHERE `timestart` >= DATE_SUB(NOW(), INTERVAL 28 DAY)
  GROUP BY unit
  ORDER BY `timestart` ASC

解释：

+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| id | select_type | table            | type | possible_keys | key | key_len | ref | rows   | Extra                                        |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| 1  | SIMPLE      | tinfinite_visits | ALL  | timestart     |     |         |     | 205897 | Using where; Using temporary; Using filesort |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+

时间：0.21460795402527

年份查询：

SELECT COUNT(DISTINCT(`identity_id`)) AS visits, DATE_FORMAT(`timestart`, '%b') AS unit
  FROM tinfinite_visits
  WHERE `timestart` >= DATE_SUB(NOW(), INTERVAL 1 YEAR)
  GROUP BY unit
  ORDER BY `timestart` ASC

解释：

+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| id | select_type | table            | type | possible_keys | key | key_len | ref | rows   | Extra                                        |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| 1  | SIMPLE      | tinfinite_visits | ALL  | timestart     |     |         |     | 205897 | Using where; Using temporary; Using filesort |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+

时间：0.50977802276611

整体查询：

SELECT COUNT(DISTINCT(`identity_id`)) AS visits, DATE_FORMAT(`timestart`, '%b') AS unit
  FROM tinfinite_visits
  WHERE `timestart` >= DATE_SUB(NOW(), INTERVAL 100 YEAR)
  GROUP BY unit
  ORDER BY `timestart` ASC

解释：

+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| id | select_type | table            | type | possible_keys | key | key_len | ref | rows   | Extra                                        |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+
| 1  | SIMPLE      | tinfinite_visits | ALL  | timestart     |     |         |     | 205897 | Using where; Using temporary; Using filesort |
+----+-------------+------------------+------+---------------+-----+---------+-----+--------+----------------------------------------------+

时间：0.52196192741394

非常非常感谢你！

4

1 回答 1

1

Salut Emilian，解释有时会随着行数而变化。

但是，由于您在分组和位置中使用计算列，您可以选择实现日期维度表。

您可以找到几乎任何数据库的日期维度表代码：

google.com/search?q=日期+维度+表格

为什么？见下文 数据仓库中的时间和日期维度

于 2013-10-01T10:45:18.693 回答