The current way of handling uuid's in MariaDB is not very user friendly. If you want to do it right you have to replace all 4 "-" chars with "" and store it in a binary(16) type and so on. That is a lot of work and sadly people start to use just varchar() for it because it's easier. But that is a huge performence problem.
To fix that i would propose to add a "uuid" datatype to MariaDB the same way PostgreSQL did it. http://www.postgresql.org/docs/9.2/static/datatype-uuid.html
That would make working with uuid's a lot easier and faster.
Thanks and greetings