To what extent is this a problem with relational databases as a whole versus MySQL in particular? Also, is it known what problems couchdb encounters as it scal

To what extent is this a problem with relational databases as a whole versus MySQL in particular? Also, is it known what problems couchdb encounters as it scales? Issues with indexing? I'm curious because JSON is a subset of Lua's primary datatype in much the same way it is Javascript's object notation - if you change surface details like braces and string quoting, it's semantically identical.