Sounds very much like 80% 20% story. 80% that was easy to do is done and now 20% that is complex and progress is slow is left to be done. Sounds very familiar from the comment in plan cache invalidation :)
On Tue, Aug 5, 2008 at 5:51 PM, Tom Lane <[EMAIL PROTECTED]> wrote: > I've pretty much finished the project I got a bee in my bonnet about > last week, which is to teach SELECT DISTINCT how to (optionally) use > hashing for grouping in the same way that GROUP BY has been able to do > for awhile. > > There are still two places in the system that hard-wire the use of > sorting for duplicate elimination: > > * Set operations (UNION/INTERSECT/EXCEPT) > > * Aggregate functions with DISTINCT > > I'm thinking of trying to fix set operations before I leave this topic, > but I'm not sure it's worth the trouble to change DISTINCT aggregates. > They'd be a lot more work (since there's no executor infrastructure > in place that could be used) and the return on investment seems low. > > Comments? > > regards, tom lane > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
