解决mysql占用cpu资源100%的问题_MySQL
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解决mysql占用cpu资源100%的问题
一个Win2003服务器,以前就跑了一个tomcat实例也没用nginx做前端代理,这个tomcat里面带了不少网站,但是访问量并不是很大,基本属于业务集中型。
解决的过程其实也挺easy,这里记录一下思路。
首先把mysql服务器升级到最新的版本,尽量避免是mysql本身问题。
然后在my.ini里面mysqld里面配置:
slow-query-log = 1
slow-query-log-file = slow.log
重启mysql这样所有'slow'的都会记录到日志里面。
然后再到慢的时候就能看到具体什么sql引发了慢的问题(slow.log在datadir下),最后发现慢的那个表查询里面username没有加索引而且并发不小,开始数据不多还没问题,后来数据多了些达到了十几万的时候,并发查没索引的表就出来问题了,每次比较十几万次字符串是挺要命。
给这个字段加上索引,马上cpu就降下来了。
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