In this column over the years, I have spent a considerable amount of time talking about contention and locking in the database tier. At the end of the day, the endless conversations about scaling the application tier boil down to less than a bag of beans if a scaled application can't go any faster because the database has hit a limit.

I have been knocking around the computer industry for a while now, and I've noticed some changes in my contemporaries and myself... For one thing, the buttons around the stomach of those old shirts that have eluded capture by my wife are looking a bit more strained than they did in the shirts' heyday.

'High performance' is what everybody strives for when putting together a new system. Technical folk often spend hours hung up on the raw speed of their code, and a certain machismo can be derived from shaving milliseconds off that pesky transaction that is the latest pride and joy. Often, this time is not very well spent.

The value of two phase commit transactions has always been that programmers can write applications that access data spread across multiple databases and be confident that any updates that are made will be consistently reflected in all of the databases, or none, at the end of the transaction.