This is like saying "Prisons are Buildings". Yes they are. So what?
EDIT: Never mind, this paper is brilliant.
EDIT2: Here's the point for my own future reference: to make a good Queue, you need a pile of parts. A reasonable construction plan for those parts is to assemble them into a Database, and throw a Queue thingy on top. This is the best way to build a Queue, because then you can use the good Database for other things too. This sort of happened and was called Redis.
EDIT: Never mind, this paper is brilliant. EDIT2: Here's the point for my own future reference: to make a good Queue, you need a pile of parts. A reasonable construction plan for those parts is to assemble them into a Database, and throw a Queue thingy on top. This is the best way to build a Queue, because then you can use the good Database for other things too. This sort of happened and was called Redis.