The entire noSQL family of servers is based on relaxing the reliability constraints of the classic ACID protections that SQL databases provided.

Each month, when you run end-of-month statements, you save that info. When you upate an account you keep a running total.

If the system crashes you then do "set corruptaccout = true where last-month plus transactions-this-month does not equal running balance". At which point you can do a brute force integrity check on those accunts.

(If I've got a 3rd state of that flag, undefined, I can even bring my database back on line immediately I've run a "set corruptaccount to undefined" command!)

And in Pick, that query will FLY! If I've got a massive terabyte database that's crashed, it's quite likely going to take a couple of hours to reboot the OS (I just rebooted our server at work - 15-20 mins to come up including disk checks etc). What's another hour running an integrity check on the data? And I can bring my database back on line immediately that query (and others like it) have completed. Tough luck on the customer who's account has been locked ... but 99% of my customers can have normal service resume quickly.

Thing is, I now *know* after a crash that my data is safe, I'm not trusting the database company and the hardware. And if my system is so much faster than yours, once the system is back I can clear the backlog faster than you can. Plus, even if ACID saves your data, I've got so much less data in flight and at risk.

But this seems to be mirroring the other debate :-) the moan about "fsync and rename" was that fsync was guaranteeing (at major cost) far more than necessary. The programmer wanted consistency, but the only way he could get it was to use fsync, which charged a high price for durability. If I really need ACID I can use BEGIN/END TRANSACTION in Pick. But 99% of the time I don't need it, and can get 90% of its benefits with 10% of its cost, just by being careful about how I program. At the end of the day, Pick gives me moderate ACID pretty much by default. Why should I have to pay the (high) price for strong ACID when 90% of the time, it is of no benefit whatsoever? (And how many SQL programmers actually use BEGIN/END TRANSACTION, even when they should?)

Cheers,
Wol