一个mysql优化的问题
<code>**log表结构如下** id int(10) primary key #主键 ip varchar(32) #ip time int(10) #时间 channel varchar(128) #渠道id 普通索引 status int(10) #状态标识 </code>
channel字段为几个渠道号channel01,channel02...channel20
status为不同的状态标识 比如1代表打开次数,2代表关闭次数等
需求是:
统计不同渠道 不同状态 每天的总ip数量
统计不同渠道 不同状态 每天的去重ip数量
统计不同渠道 不同状态 每天的新增ip数量(当天ip,且当天之前数据库中不存在的ip)
下面为统计渠道channel01,状态status=1的各项数量
目前的实现方法是:
比如2015-11-11当天的数量
先用php算出2015-11-11的凌晨时间戳$begin和2015-11-12的凌晨时间戳$end
<code>**A-- 当天ip总数 $total** SELECT COUNT(*) FROM log WHERE time>={$begin} AND time={$begin} AND time={$begin} AND time</code>
现在表中一共有52万条数据,每天新增大概3万条数据,去重后的也有2万多,在执行第四步(语句D)的时候执行时间为3秒左右
请问有没有什么办法可以优化这个sql语句,或者有没有其它的什么方法实现这个需求?
回复内容:
<code>**log表结构如下** id int(10) primary key #主键 ip varchar(32) #ip time int(10) #时间 channel varchar(128) #渠道id 普通索引 status int(10) #状态标识 </code>
channel字段为几个渠道号channel01,channel02...channel20
status为不同的状态标识 比如1代表打开次数,2代表关闭次数等
需求是:
统计不同渠道 不同状态 每天的总ip数量
统计不同渠道 不同状态 每天的去重ip数量
统计不同渠道 不同状态 每天的新增ip数量(当天ip,且当天之前数据库中不存在的ip)
下面为统计渠道channel01,状态status=1的各项数量
目前的实现方法是:
比如2015-11-11当天的数量
先用php算出2015-11-11的凌晨时间戳$begin和2015-11-12的凌晨时间戳$end
<code>**A-- 当天ip总数 $total** SELECT COUNT(*) FROM log WHERE time>={$begin} AND time={$begin} AND time={$begin} AND time</code>
现在表中一共有52万条数据,每天新增大概3万条数据,去重后的也有2万多,在执行第四步(语句D)的时候执行时间为3秒左右
请问有没有什么办法可以优化这个sql语句,或者有没有其它的什么方法实现这个需求?
你的这个表有很大问题。
IP不该用varchar(32),你想后续查询时,这比较得多低效。通用的做法是用unsigned int配合inet_aton函数。
类似的channel字段,如果固定不变,可以用enum代替varchar. 在varchar(128)上建索引,没有比这更低效的了。实在不想用enum可以考虑对局部做索引,比如前12个字符,具体看情况。
time字段应该纳入索引。你建一个索引,包含三个字段(channel, status, time),顺序很重要,少的在前多的在后。
d中in的效率比较低,用所有ip减1天前所有ip,group by 默认显示最上面的一条数据,时间上可能还要排序吧
去重IP的SQL可以使用如下改进:
B) 当天ip去重数
<code>SELECT COUNT(DISTINCT ip) FROM log WHERE time >= {$begin} AND time </code>
C) 当天ip去重列表
<code>SELECT DISTINCT ip FROM log WHERE time >= {$begin} AND time </code>
D) 当天ip在当天之前出现过的去重数量 写法类似于B
这种问题应该用计数器来解决,尽量避免复杂逻辑查询,不然数据量足够多的时候很难搞的。
计数器可以直接用db或者memcache,redis之类来做。
或者每天定时跑脚本进行数据统计,实时查看mysql不合适

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