After a reinstall, all of the old data still shows inside the MySQL/data folder, but is not actually loaded into the database.
Is there any way to have MySQL scan it's data folder and / or reimport the old folders it has from its previous install?
[Some data was changed after the last backup / export - partially my fault - so I would rather it recognize the folders rather than reimporting the SQL files.]
If the data is in the correct folder, it will be visible in MySQL, or you will get errors when the server starts. Check /var/log/messages and your MySQL error log (as defined in your config).
If you don't get any errors and can't see the data, it's likely that the data path in my.cnf is pointing to a different folder.
The above are good ideas. To recover backup from an existing backup directory with zero effect on any existing database:
- change my.cnf / my.ini to your backup folder (if you don't have OUCH - do it in the future !!!)
- restart MySQL service
You are now running from your backup, so do a MySQL dump for data tables you need
- change my.cnf / my.ini to your active folder
- restart MySQL service
- import your dumped MySQL
来源：https://stackoverflow.com/questions/2845015/importing-old-mysql-data-folder