Re: WIP Patch for GROUPING SETS phase 1

On Thu, Aug 21, 2014 at 11:01 AM, Andrew Gierth
<andrew@tao11.riddles.org.uk> wrote:
>>>>>> "Heikki" == Heikki Linnakangas <hlinnakangas@vmware.com> writes:
>  Heikki> Uh, that's ugly. The EXPLAIN out I mean; as an implementation
>  Heikki> detail chaining the nodes might be reasonable. But the above
>  Heikki> gets unreadable if you have more than a few grouping sets.
>
> It's good for highlighting performance issues in EXPLAIN, too.

Perhaps so, but that doesn't take away from Heikki's point: it's still
ugly.  I don't understand why the sorts can't all be nested under the
GroupAggregate nodes.  We have a number of nodes already (e.g. Append)
that support an arbitrary number of children, and I don't see why we
can't do the same thing here.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company