I tend to take the view of RDBMS works until it doesn't. Most cases that things like click data or event data that ends up taking billions of rows, in which cas

I tend to take the view of RDBMS works until it doesn't. Most cases that things like click data or event data that ends up taking billions of rows, in which case you aren't going to want it in a RDBMS anyways (you'd like to, but hah). I'd like LevelDB on MySQL personally.