Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
> You could probably persuade it that hashed aggregation will be okay by
> increasing sort_mem sufficiently. But it would also be interesting to
> see if the number-of-groups estimate can be improved ... 15122 is rather
> badly off from the true value of 31 ...
My sort_mem is already quite large, 53M. I think that's large enough even for
15,122 rows.
--
greg