> The downside of sharding is operationally it's a pain I am really curious about this premise. Isn't it only a pain if there's no direct system support? (i.e.

> The downside of sharding is operationally it's a pain I am really curious about this premise. Isn't it only a pain if there's no direct system support? (i.e. you have to manually rebalance shards, split up queries at the application layer, etc.) Isn't this the whole thing that NewSQL systems are trying to solve? Moreover, I don't quite understand what benefits a hierarchical structure provides that a flat (or mostly-flat) partitioning scheme doesn't, ceteris paribus in terms of system support. Especially: doesn't a hierarchical structure mean it takes O(log n) round trips to resolve a lookup rather than just O(1) as in a flat partitioning?