XML::SemanticDiff could do it if my files were in the filesystem. But as I said: They are read from a database.

So, why is that a problem ? Doesn't matter, this is perl. Try either IO::Scalar or IO::String

I believe this question has come up before, so I'd super search if I were you.

update: upon closer examination, XML::SemanticDiff is built on XML::Parser, so no need for IO::Scalar or IO::String.