"Merlin Moncure" <> writes:
> right, i see that it's actually the 'group by' that does it:
> select a, b from foo join (select a, b from bar group by a,b) q using (a,b);
> is enough to keep it from using the index on a,b from bar. thats too bad...
Some day it'd be nice to be able to reorder grouping/aggregation steps
relative to joins, the way we can now reorder outer joins. Don't hold
your breath though ... I think it'll take some pretty major surgery on
regards, tom lane