"Other systems take a different approach. CouchDB was designed as a replacement for Lotus Notes, for scenarios where [disconnected] users might each have a laptop on a plane, updating copies of the database. If I'm on a plane I need to be able to edit a document; if you're on a plane you need to be able to edit a document. You can't just lock people out. That's a different scenario to a typical web-based server application.
Typically, how would costs compare between creating a NoSQL analytics system and an equivalent open-source SQL-based one?
"The high-end relational analytics stuff isn't open-source. We are competing with the traditional enterprise software: Oracle, SAP. A better comparison would be to Oracle.
"If the system is small enough to run on an inexpensive commodity server then maybe it's equal. If you need more power than that, in the relational world you might go out and buy a big [Oracle] Exadata box for $10m, or whatever. But in our world the way to get more power is just to buy more cheap commodity servers. One $10m server will typically have less processing power than a rack full of 50 cheap commodity servers that cost $5k each or $250k in total.
"Storage will typically cost less because people will use commodity and local storage, maybe with some replication, rather than an expensive SAN. So less on servers, less on storage and less on support – our support costs tend to be about 20 per cent of Oracle support costs.
"Then there's development costs and time, and the agility and ease with which people can get things done. The Cabinet Office in the UK told us that they were able to build an entire application in Mongo faster than they could write the RFP to hire a system integrator to build the same application in Oracle."
And Larry. Does he write? Does he call?
"I hope he doesn't think of us at all! I worked there for nine years and I don't check in."