@elvinyung I am going to try to be as positive as I can. I understand why someone who hasn't written a database or who focused on the internals would see spark as similar to cockroach. Frankly they aren't even similar. Things like isolation levels, data distribution strategies and computational placement are very different in the two systems. They really aren't similar. That being said I think both of them are junk. They are the best junk out there, but junk nonetheless. So maybe take my opinion with a grain of salt.