Hello there, Bapt. > Hello, > > On Ubuntu 19.04, which uses packages mariadb-server 10.3.17 and > mysql-server 5.7.27, I noticed that if I wanted to switch from MySQL to > MariaDB, the database is corrupted and there is a complete data loss > even if I switch back to MySQL.
> I noticed that if I wanted to switch from MySQL to > MariaDB, the database is corrupted The following text does not refer to any specific error at MySQL -> MariaDB mirgration. While it's of interest on its own, it also can bring in few details to what went wrong at the restoring attempt. Cheers, Andrei > In the previous version of Ubuntu, switching from MySQL to MariaDB did > not manage to import data automatically (unlike Debian) but at least it > created a backup of the data in /var/lib/mysql-5.7/ folder which is not > done anymore. > > Here is the error message I saw during install when trying to use the > database corrupted by MariaDB and switching back to MySQL: > "MySQL has been frozen to prevent damage to your system. Please see > /etc/mysql/FROZEN for help." > > And in /var/log/mysql/error.log: > "[ERROR] InnoDB: Unsupported redo log format. The redo log was created > with MariaDB 10.3.17. Please follow the instructions at > http://dev.mysql.com/doc/refman/5.7/en/upgrading-downgrading.html"; > > I was able to reproduce the issue with a clean installation of Ubuntu > 19.04 in VirtualBox. > > Do you know where the problem comes from and if it is possible to fix > the binary data from /var/lib/mysql/ to make it work with either MySQL > or MariaDB? > It looks like MariaDB tried to convert the data ("[ERROR] InnoDB: > Unsupported redo log format") but now it fails with both MySQL and MariaDB. > Is it possible to revert the changes done by MariaDB to make the data > work again with MySQL? (and then do a proper backup with mysqldump) > > Thanks. > > _______________________________________________ > Mailing list: https://launchpad.net/~maria-discuss > Post to : maria-discuss@lists.launchpad.net > Unsubscribe : https://launchpad.net/~maria-discuss > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : maria-discuss@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp
