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mysql优化之路----hash索引优化_MySQL

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WBOYOriginal
2016-06-01 13:05:541029browse

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

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);

alter table t1 add index crcmsg(crcmsg);

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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