I had a similar problem before under Arch Linux. (This is likely not a
distribution-specific issue.) I could fix it by migrating the database
manually, see https://bugs.archlinux.org/task/63025#comment180073
However, I haven't run into any problems recently (using the latest TW
Note that the MariaDB backend seems to be upstream's default choice; at least
all distributions I've came across so far use it as default.