> > And in v6.1. If b is a space (rather than a NULL), then the behaviour is correct
> > so it must be a problem in grouping NULLs.
> >
>
> explain select b,c,sum(a) from foo group by b,c; -- gives...
>
> Aggregate (cost=0.00 size=0 width=0)
> -> Group (cost=0.00 size=0 width=0)
> -> Sort (cost=0.00 size=0 width=0)
> -> Seq Scan on foo (cost=0.00 size=0 width=28)
>
> There sort is there before the grouping operation, so this would seem to point to
> the sort code incorrectly setting something when handling NULLs.
>
> This doesn't seem like the same bug that Vadim found since a small data set such as
> this one _shouldn't_ be going out to a tape file.
We have a NULL sort patch for psort in 6.3. Are you running the most
recent sources?
--
Bruce Momjian
maillist@candle.pha.pa.us