压缩MySQL数据文件的妙招_MySQL
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MySQL数据文件如果过大,能否进行压缩呢?答案是肯定的。下面就教您一个压缩MySQL数据文件的方法,希望对您能有所帮助。
MySQL使用一段时间后,MySQL数据文件ibdata会增长得很大(主要是针对innodb的存储方式,有大量插入删除操作的数据库),有没有很好的办法可以收缩(shrink)MySQL数据文件呢?在网上查了一下,没有太好的办法,只提到删除重建MySQL数据文件的方式,实际就是备份-删除-恢复的方法,我试验了一下,基本可行,但还是有一些注意事项:
1. 用mysqldump等工具导出数据我的数据库使用latin1字符集,必须强制在参数里指定(否则默认按UTF8导出中文会变乱码):mysqldump ——add-drop-table ——user=root ——flush-logs ——default-character-set=latin1 ——password=mysql mydbname > c:/bak_all.sql注意SQLyog等工具也提供导出类似导出功能,但它们的导出不一定好用,有可能导出来后有乱码或不能执行。
2. 停止 mysqld (也就是mysql的服务)
3. 删除ibdata*, ib_logfile* 文件,最好连你的用户数据库目录一起删除,不然导回时可能报错
4. 重新启动 mysqld(这时mysqld就会自动创建 idbdata*, ib_logfile* 文件)
如果前面已删除了数据库目录,这是需要重建一个你的用户数据库(用SQLyog等工具建新数据库非常简单)
5. 将导出来的数据导回去,体积才会减小。
可以使用命令:mysql ——user=root ——password=mysql mydbname 当然,也可以在SQLyog的查询工具里执行sql文件来恢复。
另外,提供一个小技巧,如果你的帐号密码带有空格,在命令行怎么输入呢?
很简单,在你的帐号密码两边带上英文双引号 " (注意不是单引号)。比如:mysqldump ——add-drop-table ——user=root ——flush-logs ——default-character-set=latin1 ——password=" " mydbname > c:/bak_all.sql

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