On Tue, 6 Mar 2007, Alvaro Herrera wrote:
> Also, keep in mind that there were plenty of changes in the executor.
> This stuff is not likely to be very easy to implement efficiently using
> our extant executor machinery; note that Ranbeer mentioned
> implementation of "block nested loop" and other algorithms. Not sure
> how easy would be to fold that stuff into the optimizer for multi-input
> aggregates, instead of hardwiring it to the SKYLINE OF syntax.
>
Yes, there's been a lot of working on calculating skyline efficiently,
with different sorting techniques and so on. This is the most interesting
part of the idea. You could calculate the query Ranbeer gave using pure
SQL and, perhaps, use of some covariance aggregates or something already.
Of course, it gets harder when you want to calculate across many
dimensions.
Personally, I'd love to see some of these newer data analysis
capabilities added to PostgreSQL -- or at least put out there as
interesting patches.
Thanks,
Gavin