mysql优化之路----hash索引优化

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


CREATE TABLE `t1` (
`i