我正在运行一个通过日期范围搜索连接多个表的查询,并试图弄清楚如何进一步优化它。
SELECT ACC.name AS account_name, CAMP.account_id AS account_id,CAMP.name AS campaign_name,CAMP.id AS campaign_id,ADG.id AS adgroup_id,ADG.name AS adgroup_name,KW.text AS keyword_name,
SUM(SPENT.billed_clicks) AS billed_clicks,KW.id AS keyword_id,KW.status_id AS status_id FROM account ACC, campaign CAMP,adgroup ADG,adgroup_keyword KW INNER JOIN keyword_spent SPENT
ON KW.id = SPENT.keyword_id WHERE summary_date >= '2012-03-01' AND summary_date <= '2012-03-04' AND KW.adgroup_id = ADG.id AND ADG.campaign_id = CAMP.id AND CAMP.account_id = ACC.id
GROUP BY keyword_id
对此的解释产生以下结果 -
+----+-------------+-------+--------+----------------------------+--------------+---------+---------------------------------+--------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+--------+----------------------------+--------------+---------+---------------------------------+--------+----------------------------------------------+
| 1 | SIMPLE | SPENT | range | summary_date | summary_date | 3 | NULL | 752191 | Using where; Using temporary; Using filesort |
| 1 | SIMPLE | KW | eq_ref | PRIMARY,FK1948D0E6ED3A5544 | PRIMARY | 8 | clicksummarydb.SPENT.keyword_id | 1 | |
| 1 | SIMPLE | ADG | eq_ref | PRIMARY,FKBBC2083C29112FD0 | PRIMARY | 8 | advertisedb.KW.adgroup_id | 1 | |
| 1 | SIMPLE | CAMP | eq_ref | PRIMARY,FKF7A90110246F33C4 | PRIMARY | 8 | advertisedb.ADG.campaign_id | 1 | |
| 1 | SIMPLE | ACC | eq_ref | PRIMARY | PRIMARY | 8 | advertisedb.CAMP.account_id | 1 | |
+----+-------------+-------+--------+----------------------------+--------------+---------+---------------------------------+--------+----------------------------------------------+
keyword_spent 表包含超过 150 万行,这里是其上的 show create 表
| keyword_spent | CREATE TABLE `keyword_spent` (
`id` bigint(20) NOT NULL auto_increment,
`summary_date` date NOT NULL,
`adgroup_id` bigint(20) NOT NULL,
`keyword_id` bigint(20) NOT NULL,
`billed_clicks` int(11) default NULL,
`un_billed_clicks` int(11) default NULL,
`spent` decimal(20,5) default NULL,
`last_click_recno` bigint(20) default NULL,
`campaign_id` bigint(20) NOT NULL,
`account_id` bigint(20) NOT NULL,
`total_convs` bigint(20) unsigned default '0',
PRIMARY KEY (`id`),
UNIQUE KEY `keyword_spent_uniq` (`summary_date`,`adgroup_id`,`keyword_id`),
KEY `idx_account_id` (`account_id`),
KEY `idx_kw_id` (`keyword_id`),
KEY `adgroup_id` (`adgroup_id`),
KEY `campaign_id` (`campaign_id`),
KEY `summary_date` (`summary_date`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
我不明白为什么当该日期范围内的记录不超过 100,000 条时,要扫描近 750,000 行。
另外,为什么要进行文件排序而不是使用索引。?