>>> Emmanuel Cecchet <manu@frogthinker.org> wrote:
> There was an interesting comment by Oracle folks: Oracle does
> not provide serializability but only snapshot isolation, and still
users
> prefer to 'downgrade' to read committed for better performance. The
> Oracle guys experience seemed to indicate that there was no need for
> serializability (well, that's also less work for them ;-)) in their
> customer base.
Although I note that, while this work was done in 2006 at the
University of Sidney, Mr. Cahill is now an employee of Oracle
Corporation....
The interesting thing about this technique is that it works without
the kind of blocking which is the bane of other implementation
techniques. Reads don't block writes or vice versa. In my receipt
example, the fact that there is a transitory state where the view of
the data would not be consistent would cause no problems unless
someone actually tried to view the data within that (probably very
small) window of time.
-Kevin