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mysql优化之路----hash索引优化

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Release: 2016-06-07 16:28:35
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创建表 CREATE TABLE `t1` (`id` int(11) NOT NULL AUTO_INCREMENT,`msg` varchar(20) NOT NULL DEFAULT '',`crcmsg` int(15) NOT NULL DEFAULT '0',PRIMARY KEY (`id`)) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 //插入数据 insert into t1 (m

创建表

CREATE TABLE `t1` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`msg` varchar(20) NOT NULL DEFAULT '',
`crcmsg` int(15) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8

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//插入数据

insert into t1 (msg) values('www.baidu.com'),('www.sina.com');

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分别给msg, crcmsg 字段添加索引

alter table t1 add index msg(msg(5));

update t1 set crcmsg=crc32(msg);

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alter table t1 add index crcmsg(crcmsg);

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开始做测试

最后数据表结构

根据key_len的长度的大小从而给数据库查询提高速度。

自己做的小测试,希望能够给您带来收获,祝您工作愉快。

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