[michwill]

> I'm more concerned about the latency

Very valid concern. That is the bottleneck, and that was the first thing we've checked.

> Isn't a lot of normal db server side operation now a fetch-from-db + do-calculation-on-client type operation?

Not if you want to find something. Calculation-on-client is probably html rendering etc.

> And a compromise client can still pull data by running query against the server right?

Yes, but it's ok if you have millions of users, each with his own private data. It would probably cost too much to break into each client's computer (imagine a million bitcoin wallers with 0.1 bitcoin each).

Currently available databases, when used with encryption, store the key in memory. So, memory dump or mitm attack could help an attacker to collect the key.