More than the size of the data read (which I'm not sure how big would actually be) I'm more concerned about the latency. Isn't a lot of normal db server side operation now a fetch-from-db + do-calculation-on-client type operation?
And a compromise client can still pull data by running query against the server right? So is the primary improvement that one cannot use database tools to easily export the full dataset? If I know correctly isn't database with encryption support also do dumps and other full db operations encrypted too?
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.
In our case, the actual computations are done on the client