David Fetter <david@fetter.org> writes:
> While kicking the tires on the new GROUPING() feature, I noticed that
> NUMERIC has no cast to bit(n). GROUPING() produces essentially a
> bitmap, although the standard mandates for some reason that it be a
> numeric type.
> I was thinking it should produce NUMERIC rather than int4 as it does
> now in order to accommodate large numbers of columns, but the
> usefulness of the bitmap is greatly increased if there's a simple CAST
> to bit(n).
Maybe INT8 would be a better choice than INT4? But I'm not sure there's
any practical use-case for more than 30 grouping sets anyway. Keep in
mind the actual output volume probably grows like 2^N.
regards, tom lane