Sean Lange (7/25/2014)
patrickmcginnis59 10839 (7/25/2014)
Getting the account balance temporarily wrong isn't a big deal, that is what the end of day reconciliation is for. And an overdraft from an account is far more likely to occur because two ATMs are being used at once than because of a uncommitted read from a database.
He might have a point here, isn't that what folks talk about regarding partitioned mode? Granted, he doesn't take into consideration page splits but that was also mentioned in the thread, so folks are covering the topic at least.
I would completely disagree here. I have real world experience here that directly contradicts this. Getting the balance correct to the penny real-time is critical when it comes to plastic cards. I saw overdraft charges in the hundreds weekly because of littering a financial application with NOLOCK. In a system with lots of activity this is not a rare thing, it is real and it happens a lot more than many people think. You can't settle a card rejection at the end of the day when the person trying to make a purchase has just been denied. Talk about some pissed off people.
His point is that getting balances correct to the penny is what reconciliations are for, and he has a point, because number one, reconciliations ARE going to get the funds, and number two, folks with plastic are legally obligated for their charges (as opposed to for instance that related bitcoin thread, folks are not tied to an anonymous account, and reconciliations don't do squat in that case).
I remember getting zapped by this, because I did two small transactions on my card, and then a third larger that overdrafted my account. The bank happily processed the third first and was able to hit me with 3 overdrafts despite applying the transactions out of chronological order (date/time) because they applied it ordered by amount descending, because its their business and I had legitimately overdrafted the account. So in my opinion, the guy is reporting reality.